be3942r05

8/9/2019 be3942r05

http://slidepdf.com/reader/full/be3942r05 1/40

European Union – Brite EuRam III

A rational mix design method for

lightweight aggregate concrete using

typical UK materials

EuroLightCon

Economic Design and Construction withLight Weight Aggregate Concrete

Document BE96-3942/R5, January 2000

Project funded by the European Unionunder the Industrial & Materials Technologies Programme (Brite-EuRam III)

Contract BRPR-CT97-0381, Project BE96-3942

8/9/2019 be3942r05


The European Union – Brite EuRam III

A rational mix design method for lightweight

aggregate concrete using typical UK materials

EuroLightCon


Document BE96-3942/R5, January 2000Contract BRPR-CT97-0381, Project BE96-3942

Although the project consortium does its best to ensure that any information given is accurate, no liability or responsibil-ity of any kind (including liability for negligence) is accepted in this respect by the project consortium, the authors/editorsand those who contributed to the report.

Acknowledgements

This report is a deliverable of Task 3 “Lightweight aggregate concrete production’ (activity 3.1.4.1). The report is pre-pared by Éanna Nolan, Taywood Engineering, with support from Taylor Woodrow Construction Ltd. and Lytag UK Ltd.For further information contact É. Nolan (+44) 181 575 46 34, Taywood Engineering, 345 Ruislip Road, Southall, Mid-dlesex UB1 2QX, UK or by e-mail [email protected]

Information

Information regarding the report:Éanna Nolan, Taywood Engineering, 345 Ruislip Road, Southall, Middlesex UB1 2QX, United KingdomTel: +44 181 5754634, e-mail: [email protected] regarding the project in general:Jan P.G. Mijnsbergen, CUR, PO Box 420, NL-2800 AK Gouda, the NetherlandsTel: +31 182 540620, Email: [email protected] on the project and the partners on the Internet: http://www.sintef.no/bygg/sement/elcon

ISBN 90 376 0394 7

8/9/2019 be3942r05


The European Union – Brite EuRam III

A rational mix design method for lightweight

aggregate concrete using typical UK materials

EuroLightCon


Document BE96-3942/R5, January 2000Contract BRPR-CT97-0381, Project BE96-3942

Selmer ASA, NOSINTEF, the Foundation for Scientific and Industrial Research at theNorwegian Institute of Technology, NONTNU, University of Technology and Science, NOExClay International, NOBeton Son B.V., NLB.V. VASIM, NLCUR, Centre for Civil Engineering Research and Codes, NLSmals B.V., NLDelft University of Technology, NLIceConsult, Línuhönnun hf., ISThe Icelandic Building Research Institute, ISTaywood Engineering Limited, GBLias-Franken Leichtbaustoffe GmbH & Co KG, DEDragados y Construcciones S.A., ES

Eindhoven University of Technology, NLSpanbeton B.V., NL

8/9/2019 be3942r05


A rational mix design method for lightweight aggregate concrete using typical UK materials

BE96-3942 EuroLightCon 3

Table of Contents

PREFACE 5

SUMMARY 7

1 INTRODUCTION 8

2 OBJECTIVES 9

3 PROGRAMME OF TESTS 10

3.1 A study of aggregate absorption properties 10

3.2 Paste characterisation using the flowcyl apparatus 10

3.3 Workability prediction of LWA concretes 11

4 LABORATORY PROCEDURES AND TEST METHODS 12

4.1 Pre batching and batching procedures 12

4.2 Concrete mix procedure 12

4.3 Concrete casting and curing procedures 13

4.4 Routine measurements on fresh and hardened concrete 13

4.5 ‘Flowcyl’ test procedure 13

4.6 Water absorption of aggregates test procedure 14

4.7 Water absorption of aggregate from a paste test procedure-Punkii-

method 14

4.8 Aggregate Vacuum Absorption measurement test procedure 15

4.9 Aggregate Pressurised absorption test procedure 15

4.10 Uncompacted Bulk Density of aggregates test procedure 16

5 RESULTS AND DISCUSSION 17

5.1 Study of aggregate moisture gain properties 17

5.1.1 Lytag 4 - 12mm - Moisture gain 175.1.2 Liapor 8 : 4 - 8 mm size - Moisture gain 18

5.1.3 The influence of ‘pumpaid’ admixture on absorption into lightweightaggregates 19

5.1.4 The influence of ‘pumpaid’ admixture on absorption from pasteinto Lytag 20

5.2 Characterisation of pastes using the ‘flowcyl’ apparatus 20

5.3 Estimation of mix workability using paste and aggregate

characteristics 22

6 CONCLUSIONS 27

8/9/2019 be3942r05




7 REFERENCES 28

8 NOMENCLATURE 29

Appendices

A S-curve – aggregate parameter determination 30

B S-curves for concretes investigated 32

C 28 Day compressive strength, workability and density data 38

D Mix recipes 39

8/9/2019 be3942r05




PREFACEThe lower density and higher insulating capacity are the most obvious characteristics of Light-

Weight Aggregate Concrete (LWAC) by which it distinguishes itself from ‘ordinary’ Normal

Density Concrete (NDC). However, these are by no means the only characteristics, which jus-

tify the increasing attention for this (construction) material. If that were the case most of the de-

sign, production and execution rules would apply for LWAC as for normal weight concrete,

without any amendments.

LightWeight Aggregate (LWA) and LightWeight Aggregate Concrete are not new materials.

LWAC has been known since the early days of the Roman Empire: both the Colosseum and thePantheon were partly constructed with materials that can be characterised as lightweight aggre-

gate concrete (aggregates of crushed lava, crushed brick and pumice). In the United States, over

100 World War II ships were built in LWAC, ranging in capacity from 3000 to 140000 tons and

their successful performance led, at that time, to an extended use of structural LWAC in build-

ings and bridges.

It is the objective of the EuroLightCon-project to develop a reliable and cost effective design

and construction methodology for structural concrete with LWA. The project addresses LWA

manufactured from geological sources (clay, pumice etc.) as well as from waste/secondary ma-

terials (fly-ash etc.). The methodology shall enable the European concrete and construction in-

dustry to enhance its capabilities in terms of cost-effective and environmentally friendly con-struction, combining the building of lightweight structures with the utilisation of secondary ag-

gregate sources.

The major research tasks are:

Lightweight aggregates : The identification and evaluation of new and unexploited sources spe-

cifically addressing the environmental issue by utilising alternative materials from waste. Fur-

ther the development of more generally applicable classification and quality assurance systems

for aggregates and aggregate production.

Lightweight aggregate concrete production : The development of a mix design methodology to

account for all relevant materials and concrete production and in-use properties. This will in-

clude assessment of test methods and quality assurance for production.

Lightweight aggregate concrete propert ies : The establishing of basic materials relations, the

influence of materials characteristics on mechanical properties and durability.

Lightweight aggregate concrete structur es : The development of design criteria and -rules with

special emphasis on high performance structures. The identification of new areas for applic a-

tion.

The project is being carried out in five technical tasks and a task for co-ordination/management

and dissemination and exploitation. The objectives of all technical tasks are summarised below.

Starting point of the project, the project baseline, are the results of international research work

combined with the experience of the partners in the project whilst using LWAC. This subject is

8/9/2019 be3942r05




dealt with in the first task.

Tasks 2-5 address the respective research tasks as mentioned above: the LWA itself, production

of LWAC, properties of LWAC and LWAC structures.

Sixteen partners from six European countries, representing aggregate manufacturers and suppli-ers, contractors, consultants research organisations and universities are involved in the Eu-

roLightCon-project. In addition, the project established co-operation with national clusters and

European working groups on guidelines and standards to increase the benefit, dissemination and

exploitation.

At the time the project is being performed, a Working Group under the international concrete

association fib (the former CEB and FIP) is preparing an addendum to the CEB-FIP Model Code

1990, to make the Model Code applicable for LWAC. Basis for this work is a state-of-the-art

report referring mainly to European and North-American Standards and Codes. Partners in the

project are also active in the fib Working Group.

General information on the EuroLightCon-project, including links to the individual project part-

ners, is available through the web site of the project: http://www.sintef.no/bygg/sement/elcon/

At the time of publication of this report, following EuroLightCon-reports have been published:

R1 Definitions and International Consensus Report. April 1998

R1a LightWeight Aggregates – Datasheets. Update September 1998

R2 LWAC Material Properties State-of-the-Art. December 1998

R3 Chloride penetration into concrete with lightweight aggregates. March 1999

R4 Methods for testing fresh lightweight aggregate concrete, December 1999

R5 A rational mix design method for lightweight aggregate concrete using typical UK materi-

als, January 2000

8/9/2019 be3942r05




SUMMARYThis investigation examined the properties of typical UK lightweight aggregates, Liapor 8 and

Lytag. The water absorption characteristics of the aggregates were examined in the 'as received'

and oven dried state. Typical UK Lightweight aggregates were found to attain a moisture con-

tent close to their maximum moisture capacities, under typical pumping pressures of 4.5 MPa.

The addition of a proprietary pumpaid to the absorption water was found not to influence the

amount of moisture absorbed by lightweight aggregates.

The Punkii- method8 of assessing the quantity of moisture absorption of aggregates from a paste

was found to yield results of large variability. The results attained suggested little difference in

the absorption by lightweight aggregate from a paste without and containing pumpaid.

The ‘flowcyl’ method of paste characterisation was successfully used to view the influence of

pumpaid and superplasticiser dose on the flow properties of three selected water cement ratio

pastes. 'Optimum' levels of superplasticiser were selected for further work on the basis of this

study.

New workability prediction functions for use in the 'flowcyl' mix design method for lightweight

aggregate concrete are proposed on the basis of a series of mix trials carried out. The workabil-

ity of lightweight concretes was found to change more rapidly with increasing matrix overfill

content compared to normal density concrete.

Lightweight aggregate concretes manufactured with Liapor 8 were found to produce concretes

with a more advantageous strength / density relationship than concrete made from UK Lytag.

Keywords

Lightweight aggregate concrete, aggregate absorption, Flowcyl, mix design, workability,

pumpaid

8/9/2019 be3942r05




1 INTRODUCTIONAlthough lightweight concrete is not a new material, its design and use is not as well accepted

as normal weight concrete. This is despite a range of applications in which it offers technical

advantages over normal weight concrete. That lightweight concrete is not well accepted is

mainly due to a higher cost of material, a lack of confidence in it’s properties, and a lack of gen-

erally accepted guidelines.

This report forms part of Brite Euram ‘EuroLightCon Project’ the objective of which is to de-

velop a reliable and cost effective design and construction methodology for structural concrete

made with light weight aggregates. The overall objective of this project is to address this lack

of confidence and provide guidelines for the use of lightweight aggregate concrete.

Task 3 of the ‘EuroLightCon’ project, of which this report forms a part, investigates lightweight

aggregate concrete production. The main sub tasks are :

To develop a mix design method with particular focus on production properties, standard com-

pliance requirements like density, strength, durability and costs. The method will be based on a

set of characteristic properties of the constituents determined by both existing and new methods.

To evaluate test methods of LWA concrete in the fresh state and develop new methods if neces-

sary.

To develop a quality assurance procedure for LWA concrete production, transport, placing and

compaction, especially when it is different from normal density concrete.

The mix design method described in item 1 above, is based on the Norwegian ‘S-curve’ mix

design and the work described in this report fits into the development of this method for use

with Lightweight aggregate concrete.

This investigation examines the properties of typical UK lightweight aggregates, characterises

several concrete matrices in terms of the Norwegian ‘flowcyl’ method and examines the rela-

tionship between workability and matrix content for lightweight aggregate concretes.

8/9/2019 be3942r05




2 OBJECTIVESThe objectives of this sub-activity are to:

1. Assess the water absorption of typical UK lightweight aggregates, taking pumping

into consideration.

2. Characterise the paste fraction of high strength concrete mixes using the ‘Flowcyl’

test.

3. Create a range of mixes to measure the workability of selected lightweight aggregate

concretes.

4. To make the data generated available for inclusion in the development of a rational-

ised mix design.

8/9/2019 be3942r05




3 PROGRAMME OF TESTSThe following test programme was devised to achieve the stated objectives of sub-activity

3.1.4.1. Three main studies were planned to address the objectives.

3.1 A study of aggregate absorption propertiesThe variables considered are shown in table 1 below.

Table 1 - Variables in the study of lightweight aggregate absorption properties

Aggregate typeLiapor 8 : 4 - 8 mm size

Lytag 4 -12 mm size

(pumping grade)Moisture condi-

tionAs Received moisture condition Oven Dry moisture condition

Water application

method

Normal pressure

absorption

Vacuum

ApplicationPumping pressure

Water additions With pumpaid Without pumpaid

A further part of this study included an assessment of the actual absorption of water into the

lightweight aggregate from a paste.

3.2 Paste characterisation using the flowcyl apparatusTable 2 shows the variables considered in the characterisation of pastes

Table 2 - Variables for paste characterisation study

Nominal water cement

ratio of paste0.25 0.30 0.35

Superplasticiser

content

Various between 0% and 3%

(fluid volume by weight of cement l/kg)

Pump-aid No pumpaid1% pumpaid fluid volume

by weight of cement)

Note : water cement ratio of the mix includes allowance for water absorption of the aggre gates but not

water included as part of the admixtures. See relevant text for further details.

8/9/2019 be3942r05




3.3 Workability prediction of LWA concretesTable 3 shows the variables considered in the study of workability prediction of lightweight

concrete aggregate mixes.

Table 3 - Variables used in study of workability prediction of lightweight concrete mixes.

Nominal

w/c ratio of Mix0.25 0.30 0.35

Paste content of

mix

Various - chosen to give spread of workabilities

Aggregate type Liapor 8

4-8 mm size

Lytag 4 -12 mm size

(pumping grade)

Note : Water cement ratio of the mix includes allowance for water absorption of the aggregates but not

water included as part of the admixtures. See relevant text for further details.

8/9/2019 be3942r05




4 LABORATORY PROCEDURES AND TEST METHODS

4.1 Pre batching and batching procedures1. Particle and Bulk densities of the normal weight sand and lightweight coarse aggregates

were predetermined using standard test methods (BS 812 : Part 2 (1)). All sand used in this

investigation was natural marine dredged sand of normal density.

2. The nominal 'as received' saturation contents of the two LWA used in this investigation

were Liapor 17% moisture content and Lytag 11% moisture content unless otherwise stated.

Exact determinations of moisture content were made for each concrete mix, as detailed be-

low.

3. Aggregates required for the mix were put into a large pan mixer and mixed briefly. The blended aggregates were then re-bagged separately ready for use in trial mixes.

4. Moisture contents (24 hours drying in a conventional oven at 105 Degrees C) were taken

from the blended constituent sand and lightweight coarse aggregates.

5. The moisture correction for the sand used in the mix was calculated by comparing the

measured moisture content with the moisture content of the saturated surface dry sand (us-

ing BS 812 : Part 109: method (2)). A correction to the quantity of water in the mix was

then calculated.

6. A sample of LWA was selected and it’s 30-minute water absorption measured directly.

This test was carried out on the day of mixing with the sample taken from the aggregates

blended for use in the mix. The resulting water absorption (expressed as a percentage of

initial weight) was assumed to represent the quantity of moisture that was absorbed into theLWA during mixing and casting. A correction to the quantity of water to be added to the

mix was then calculated.

7. The final mix design with corrected water and adjusted aggregate batch weights was then

adopted in accordance with the calculation shown in Appendix D.

All constituents were batched by weight (mix design was based on volume).

4.2 Concrete mix procedure1. The air temperature of the laboratory was measured prior to each mix.

2. The mix pan and mixer blades were dampened prior to mixing.3. The water to be added to the mix was combined with the superplasticiser prior to addition to

the mix.

4. The lightweight coarse aggregate was added to the mix pan along with two thirds of the wa-

ter (including superplasticiser) to be added to the mix. After a brief period of mixing, the

pan was covered with plastic sheeting and allowed to stand for 15 minutes.

5. The required cement was then added, immediately followed by the required sand.

6. The mixture was then mixed for 60 seconds after which the rest of the water and superpla s-

ticiser was added. The mix was then mixed for a further 30 seconds. The mix was then

hand mixed to ensure full mixing of the constituents.

7. If a pumpaid was required it was added at this stage of the mix.

8/9/2019 be3942r05




8. The mixture was finally mixed for a further 60 seconds

A conventional type, 50 Litre (Creteangle), pan mixer was used for all mixes.

4.3 Concrete casting and curing proceduresAll moulds and formwork shutters were oiled prior to use and were free from dust and dirt. All

compressive strength cubes were manufactured to the requirements of BS 1881 : part 108 (3).

1. Casting of standard 100 mm compressive strength cubes was carried out in two 50 mm lay-

ers. Each layer was vibrated using a vibrating table. Vibration was continued until air

stopped rising to the surface of the concrete in the cube mould. Vibration of a set of cubes

from the same mix was carried out at the same time to reduce inter-cube variation.

2. The specimens were given a troweled finish, moved to a controlled temperature laboratory

(20 °C) and covered to stop evaporation.

3. After 24 hours the cube moulds were struck and the cubes were placed in a water tank of 20°C ± 2 °C until testing at the age of 28 days.

4.4 Routine measurements on fresh and hardened concrete1. Slump (BS 1881 : Part 1024) and Flowtable (BS 1881 : Part 1055) measurements were car-

ried out, where appropriate, immediately after the completion of the mix.

2. Stripping density was carried out by a simple weight measurement of compressive strength

cubes both in air and water (not carried out for all mixes).

3. At the age of 28 days the compressive strength cubes were removed from the water (20 °C)

and excess surface moisture removed. The weight of each cube in air and in water is takento give a 28 day saturated density.

4. The cubes were then tested for compressive strength to the requirements of BS 1881 : Part

116 6.

4.5 ‘Flowcyl’ test procedure1. An electronic balance was set up underneath the flowcyl and attached to a datalogging de-

vice. The time interval between consecutive weight measurements was set to 2 seconds.

2. The mix procedure for the cement paste was carried out in accordance with reference 7.

3. After mixing, the paste was poured into the flowcyl while the lower outlet was covered to

prevent the loss of material.

4. The balance was set to zero and the data logging device switched on immediately prior to

allowing the paste to flow out of the flowcyl.

5. The weight increase on the balance with time was recorded at 2 second intervals. 6. The density of the paste was measured by filling a container of known volume and finding

the weight of the paste inside.

7. The results of the flowcyl test were calculated using a spreadsheet programme provided by

the SINTEF, Trondheim, Norway. This programme was modified to work on the English

language version of Excel. Inputs required for this programme are :

• The time interval between consecutive weight readings (n)=2.

8/9/2019 be3942r05




• The list of weight measurements recorded by the data logger device.

• The density of the paste under test.

8. After inputting these values the graph of the highlighted data were drawn and a 2nd order

polynomial was fitted to the differential data. The a, b and c parameters from the equation

of this line were back inputted into the program.9. The value of λq was then calculated and recorded.

4.6 Water absorption of aggregates test procedure1. A sample of aggregate of known moisture condition (‘As received’ or ‘Oven dried’) was

selected and weighed (W1)

2. The aggregate was then immersed in the liquid under test.

3. The aggregate was removed after a determined period of time.

4. The saturated surface dry (SSD) condition of the aggregate sample was obtained by remov-

ing surface water from the aggregate using ‘blotting type’ paper. Aggregate residue was ex-tracted from the water and paper by means of oven drying and weighed (Wr).

5. The SSD weight of the aggregate (plus any aggregate residue weight, Wr) was obtained

(W2).

6. The percentage absorption (Abs) of the aggregate was determined by Equation 1.

Abs = (W2-W1)/W1 (1)

4.7 Water absorption of aggregate from a paste test

procedure-Punkii-method(8)

1. Fifteen individualaggregate particles of known moisture content were selected for each

absorption test. The initial moisture content was recorded (MC).

2. The appropriate mortar paste (of known w/c ratio) was mixed and placed in 3 containers.

3. aggregate particles were pressed into the paste in each container and left for the required

period of absorption.

4. After the absorption period the aggregate particles were removed and the excess paste was

removed using a small brush (normally used for cleaning test sieves).

5. The aggregate particles were then individually weighed on a balance accurate to four deci-

mal places of a gram and the data was recorded. (Wa1 to Wa5)

6. The aggregate was then oven dried over a 48 hour period at a temperature of 105 °C.

7. Finally the aggregate particles were re-weighed and the weights recorded. (Wb1 to Wb5).

8. The aggregate absorption values were calculated using equation 28

( )Wabs M M

M

Wcr MC =

−

+ −

−+

−

2 3

31

1ω

ξ

ξ (2)

Where

Wabs % water absorption into aggregate particles.

M2 sum (Wa1 to Wa5)

M3 sum (Wb1 to Wb5).

8/9/2019 be3942r05




ξ ratio between chemically combined water and cement (0.0258).

Wcr effective water cement ratio of the mortar.

The following procedure was used to estimate the quantity of paste that adhered to the aggregate

after the absorption period.1 Average dried paste content on aggregate surface = ω=

[Sum (Wo1 to Wo5) - Sum (Wf1 to Wf5)] / Sum (Wf1 to Wf5).

2 Saturated surface dry aggregates were initially weighed on a balance of appropriate accu-

racy.(Wo1 to Wo5)

3 The aggregate particles were placed in the design paste.

4 The aggregate was removed and the paste was removed from each particle using a small

brush (normally used for cleaning test sieves) in exactly the same manner as above.

5 The aggregate particles were then re-weighed and the readings recorded.(Wf1 to Wf5).

4.8 Aggregate Vacuum Absorption measurement testprocedure

1. A sample of aggregate of known moisture condition (‘As received’ or ‘Oven dried’) was

selected and weighed (W1).

2. The aggregate was placed in a vacuum jar and the vacuum applied.

3. After a period of 5 minutes vacuum application, fluid (using de-ionised water) was intro-

duced into the vacuum flask without degrading the vacuum.

4. The aggregate was kept in water for a further 30 minutes while the vacuum was running.

After this period the aggregate was removed.

5. The Saturated surface dry (SSD) condition of the aggregate sample was obtained by remov-

ing surface water from the aggregate using ‘blotting type’ paper.

6. The SSD weight of the aggregate was obtained (W2).

7. The percentage absorption under vacuum (Abs) of the aggregate was determined by Equa-

tion 3.

Abs = 100 *(W2-W1)/W1 (3)

4.9 Aggregate Pressurised absorption test procedure1. A sample of aggregate of known moisture condition (As received / Oven dried ) was se-

lected and weighed (W1).

2. The aggregate was placed in pressure vessel and a quantity of water sufficient to cover the

aggregate was introduced.

3. The pressure vessel was sealed (this operation took 5 minutes) and a pressure of 4.5 MPa (≈

45 Bar or ≈ 652.5 psi) (Typical pumping pressure) was applied by means of nitrogen gas.

4. After a stated period of time, the pressure was released and the test sample was removed

from the pressure vessel.

5. The Saturated surface dry (SSD) condition of the aggregate sample was obtained by remov-

ing surface water from the aggregate using ‘blotting type’ paper.

6. The SSD weight of the aggregate was recorded (W2).

7. The percentage absorption under pressure (Abs) of the aggregate was determined by Eq. 4.

8/9/2019 be3942r05




Abs = 100 *(W2-W1)/W1 (4)

4.10 Uncompacted Bulk Density of aggregates test procedure1. A sturdy metal container was weighed empty (W1).

2. The container was then filled with water (@ 20 °C and weighed (Ww)).

3. After emptying the water and drying the container fully it was then filled with the aggregate

(in the ‘as received’ state) and levelled off with a straight edge. The weight of the container

was then recorded as (W2).

4. The volume of the container was determined by Equation 5.

Volume (V) = (Ww-W1)/1000 (5)

5. The bulk density of the aggregate was determined using Equation 6

Bulk Density = (W2-W1)/V (6)

8/9/2019 be3942r05




5 Results and discussion

5.1 Study of aggregate moisture gain properties

5.1.1 Lytag 4 - 12mm - Moisture gainThe results of the aggregate moisture gain tests for Lytag 4-12 mm and Liapor 8 : 4 - 8 mm size

are shown in figures 1 and 2 respectively.

Atmospheric absorption of the aggregates was intended to give an indication of water absorp-

tion by aggregates in the mixing procedure. It is recognised that aggregates in a moist paste do

not absorb as much moisture as from water. Use of moisture absorption from water gives a

comparative measure of absorption rather than an absolute measure.

The application of 4.5MPa (≈ 45 Bar ≈ 650 psi) of pressure was intended to represent the mag-

nitude of the force applied to the concrete by pumping to a height of 100m9.

The vacuum application was used to saturate the aggregate samples as fully as possible. This

method is commonly used to saturate porous specimens, most commonly concretes.

Figure 1 - Lytag 4 -12 mm size - Aggregate absorption properties

The ‘as received’ moisture content referred to in figure 1 was measured as 11.4 % for the Lytag

sample tested. This value was taken to be representative of the normal UK Lytag production

moisture content. Lytag UK representatives10 have indicated that the moisture content of pro-

duction is presently approximately 10%.

Figure 1 shows the results of atmospheric absorption tests on the Lytag aggregate up to a period

of 24 hours. The difference between the moisture intake of ‘as received’ and oven dried aggre-

gate is as expected, with the drier material gaining more weight.

Lytag 4 - 16 mm pumping grade

0.00

5.00

10.00

15.00

20.00

25.00

30.00

0 200 400 600 800 1000 1200 1400 1600

Time (mins)

W e i g h t G a i n ( % w . r . t i n i t i a l w g t )

Oven Dried - Vacuum Saturated

Oven Dried - 4.5 MPa

Oven Dried - Atmospheric Absorption

As Received - 4.5 MPa Pressure

As Received - Vacuum Saturated

As Recieved - Atmospheric Absorption

8/9/2019 be3942r05




Assessing the results as a whole it can be seen that the weight gain due to vacuum saturation of

the ‘as received’ aggregate is lower than might have been expected (The relationships between

weight gain in oven dried and ‘as received’ aggregates are similar for atmospheric absorption

and pressure application). This indicates that the ‘as received’ moisture in the Lytag aggregate

pores may have disrupted the vacuum saturation process.

The vacuum saturation of the oven dried aggregate indicates that the total moisture capacity of

Lytag 4 -12 mm is of the order of 25% of the oven dried weight.

The application of water at a pressure of 4.5 MPa to the ‘as received’ Lytag was found to intro-

duce more moisture into the material than either vacuum saturation or atmospheric absorption.

This highlights the fact that a pumped concrete containing Lytag could expect to loose signif i-

cant quantities of moisture from the paste into the aggregate. If the increase in moisture caused

by the application of pressure is combined with the initial moisture content of the Lytag then the

resulting moisture content of the Lytag approaches the total moisture capacity of the aggregate.

This is further reflected by the 22% moisture gain by oven dried Lytag subjected to the applica-tion of water at 4.5 MPa pressure.

5.1.2 Liapor 8 : 4 - 8 mm size - Moisture gainFigure 2 shows the results of a similar set of weight gain tests carried out on Liapor 8 : 4 - 8 mm

size aggregate. The measured ‘as received’ moisture content was 17.1%.

As with Lytag, the vacuum saturation of the ‘as received’ Liapor aggregate was not successful

with minimal weight gain due to vacuum saturation. The oven dried vacuum saturation indi-

cates that Liapor 8 has a moisture capacity of approximately 22%.

Figure 2 - Liapor 8 : 4 -8 mm size - Aggregate absorption properties

The ‘as received’ Liapor 8 material contained a lot of moisture and therefore did not have a

large atmospheric absorption. The oven dried atmospheric absorption was much larger and ex-

Liapor 8 : 4 - 8 mm size

0.00

5.00

10.00

15.00

20.00

25.00

30.00

0 200 400 600 800 1000 1200 1400 1600

Time (mins)

W e i g h t G a i n ( % w . r . t i n i t i a l w g t )

As Received - 4.5 MPa Pressure

As Received - Atmospheric Absorption As Received -

Vacuum Saturated

Oven Dried - Atmospheric Absorption

Oven Dried - 4.5 MPa Pressure

Oven Dried - Vacuum Saturated

8/9/2019 be3942r05




hibited a continued absorption after 24 hours.

As discussed above, the vacuum saturation of ‘as received’ aggregate was seen not to be suc-

cessful, with an extremely low moisture gain being evident.

The application of pressure to ‘as received’ Liapor 8 caused a significant moisture gain (≈ 6%).Again, when the initial moisture content of 17.1% is taken into consideration this means that the

Liapor aggregates could expect to be substantially saturated when subject to the types of pres-

sures associated with pumping.

Comparatively, Liapor 8 was shown to have a lower total moisture capacity than Lytag.

5.1.3 The influence of ‘pumpaid’ admixture on absorption intolightweight aggregates

Figure 3 shows the results of a study that was intended to study the influence of a pumpaid on

the atmospheric absorption of moisture into aggregates. A standard mix dose (1% liquid vol-

ume by weight of cement - for a 0.3 w/c ratio mix) of pumpaid admixture was introduced into

the water used for absorption and 24 hour absorption tests were carried out. As can be seen, no

significant difference in absorption profiles can be identified either in the case of Lytag or Lia-

por 8. Further investigation of the admixture indicated that it may only become active when in

an alkaline environment, however absorption tests which used alkaline water (pH 11.1) and

pumpaid admixture for absorption showed no reduction in absorption when compared to absorp-

tion from water alone.

Figure 3 - Influence of pumpaid on the absorption of lightweight aggregates

The results in figure 3 can not be taken as proof that the addition of pumpaid to a mix will not

influence the quantity of moisture absorbed by lightweight aggregates from a concrete mix. The

results do indicate that there is no easy way of measuring any influence that the addition of a

pumpaid may have on lightweight aggregate moisture gain in a concrete mix. The problem was

further investigated in an additional series of tests described in section 5.1.4.

8/9/2019 be3942r05




5.1.4 The influence of ‘pumpaid’ admixture on absorption from pasteinto Lytag

An investigation into Lytag absorption of moisture from paste was undertaken to further assess

the influence of pumpaid on lightweight aggregate absorption. Figure 4 shows the results of

this study. The method used to measure the absorption from paste is described in section 4.7.There is no readily identifiable trend between absorption from paste containing pumpaid and

paste not containing pumpaid. One negative result suggests that ‘as received’ Lytag lost water

to the paste. It is much more likely that this result illustrates a large variability associated with

the method used rather than describing a real phenomenon. The results suggest that there is no

large difference in absorption from paste with and without pumpaid although it is acknowledged

that a large variability is present in the results obtained.

Figure 4 - Water absorption from paste with and without pumpaid admixture

5.2 Characterisation of pastes using the ‘flowcyl’ apparatusFigure 5 shows the full results of the paste characterisation study. The flowcyl Lambda Q (λq)

is a measure of the ability of the paste to flow through a standard flowcone 7, 11. The lower the

value of λq the more fluid the paste and a λq = 1 denotes a paste with no flow. In general the

three pastes investigated had low w/c ratios and were found to be reasonably stiff.

The lower w/c ratio pastes were seen to have higher λq values and therefore were more viscous.

The higher 0.35 w/c ratio paste can be seen to have lower λq values and flowed more freely

through the standard cone.

The superplasticiser (a melamine based product) content is a fluid weight expressed as a per-

centage of the cement content. The solids content of the superplasticiser is 38% and this has not

been included in the nominal w/c ratio, see table 4. Fines <0.125 mm were included in each

8/9/2019 be3942r05




paste in proportion to their quantity in a full scale mix containing 60% coarse lightweight ag-

gregate and 40% normal density sand.

‘Optimum’ S/Pfor use with

pupaid shownin each case

Figure 5 - Flowcyl Lambda values versus superplasticiser content for 3 selected pastes

As the quantity of superplasticiser (38% solids content) in each of the pastes increased, the flu-idity of the paste increased until it reached a ‘plateau’ level. The addition of more superplasti-

ciser in excess of the ‘plateau’ level had a much reduced effect. This ‘plateau’ level of super-

plasticiser addition was judged to denote an 'optimum' superplasticiser content. The higher w/c

ratio paste had a clearly defined 'optimum' level whereas choosing an 'optimum' level for the

0.25 w/c ratio paste was more subjective. Table 4 shows the 'optimum' levels of superplasticer

content chosen from figure 5.

Table 4 - 'Optimum' superplasticiser contents (based on figure 5)

Nominal water cement ratio (w/c)* 0.25 0.30 0.35

'Optimum' Superplasticiser content

(%)**3.0 2.5 1.5

'Optimum' superplasticiser content

used with pumpaid (%)**2.25 1.5 1.0

* Nominal water cement ratio. See table 5.

** fluid volume expressed as a percentage of the cement content

The addition of a standard dose of 1% fluid volume by weight of cement of pumpaid admixture

(2.5% solids content) was added to each of the cement pastes. The pumpaid admixture is de-

signed to make a concrete more cohesive and therefore less prone to segregation during pump-

8/9/2019 be3942r05




ing. After pumping, the concrete is reworked for a short period until the concrete returns to its

original condition. Therefore, the amount of mixing is critical as too much mixing would work

out the influence of the admixture. A constant period of 60 seconds mixing after the addition of

the pumpaid was adopted and used for all mixes in this study.

The influence of the pumpaid on the fluidity of paste can be seen from figure 5. The solid lines

represent the paste flow characteristics without pumpaid or when the influence of pumpaid has

been worked out. The dashed lines represent the paste flow characteristics with the pumpaid

'active'. The pumpaid can be seen to make the concrete less fluid over a range of superplasti-

ciser contents for each paste. The increase in workability in pastes containing pumpaid occurs

over a smaller range of superplasticiser contents than in ordinary pastes. Experimental observa-

tion indicated that for each of the three pastes investigated, an increased superplasticiser content

resulted in a reduced time taken to mix out the influence of pumpaid. Where values of paste

including pumpaid are similar to those without pumpaid, the influence of the pumpaid has been

worked out by the 60 second standard ‘post pumpaid’ mixing time.

The most effective dose of superplasticiser for use with the stated dose pumpaid is estimated as

the largest difference between the λq values for pastes with and without pumpaid (shown in ta-

ble 4). In reality dosing trials on-site are likely to produce a more practical estimate of an 'opti-

mum' dose / time of addition etc.

The ''Optimum'' doses of superplasticiser for use with superplasticiser and pumpaid (from table

4) were adopted for all concrete mixes manufactured in this investigation. As admixture doses

were based on the weight of cement in each mix and fixed to a 'optimum' dose for each nominal

water cement ratio, actual free water cement ratios can be calculated. This resulted in the desig-

nated nominal water cement ratios having actual water cement ratios as detailed in table 5.

Table 5 - Nominal and Actual w/c ratios for pastes and concretes

Nominal water cement ratio (w/c) 0.25 0.30 0.35

Actual w/c ratio with mixes including

superplasticiser0.264 0.309 0.356

Actual w/c ratio with mixes including

superplasticiser and pumpaid0.274 0.319 0.366

Water cement ratios quoted in this report are nominal water cement ratios unless otherwise

stated.

5.3 Estimation of mix workability using paste and aggregatecharacteristics

The full set of slump, flow, density and 28 day compressive strength data for 0.25, 0.3 and 0.35

nominal w/c ratio concretes made with both Lytag and Liapor 8 aggregates is given in Appendix

B. Figures 6 and 7 show the results of slump and flow measurements for 0.3 nominal w/c ratio

concrete mixes made with Lytag and Liapor 8 lightweight aggregates respectively.

8/9/2019 be3942r05


8/9/2019 be3942r05




namely the flow resistance of the paste (λq) and various aggregate factors combined into the

term (Hm). Full details of the aggregate test results and the calculation of Hm are presented in

Appendix A.

The original functions proposed by Mørtsell7, 11

to describe the change of slump and flow withchange in matrix content were found not to predict the workability of lightweight aggregate

concretes. Therefore the function was modified to fit the lightweight data.

Mørtsell’s method of predicting slump includes the sub function, α - slump (Equation 7), and α

- spread (Equation 8) which influences the rate at which the concrete workability changes from

minimum to maximum with changing matrix content.

α - slump = 115 * EXP (-4.45 * λq) (7)

α - spread = 115 * EXP (-4.45 * λq) (8)

By changing the functions to

α - slump(mod) = 115 * EXP (-2.225 * λq) (9)

α - spread(mod) = 115 * EXP (-2.225 * λq) (10)

It was found that the modified prediction functions generally fitted the data obtained from

lightweight aggregate concrete (shown in figures 6 and 7 and Appendix B). This function is

only a first approximation of the lightweight aggregate concrete s-curve, more extensive data is

required. The modified prediction functions (equations 9 and 10) have been used in all the ma-

trix-slump graphs in this report and appendices unless otherwise stated.

The difference between the original and modified s-curve functions can be assessed by compar-

ing two slump s-curve functions graphically (figure 8).

Figure 8 - Comparison of normal weight concrete and modified ‘lightweight’Slump S-curve prediction functions

It is evident that the change of slump with change in matrix content of a mix is much more

abrupt in LWA concrete than in NDC. The aggregate density, therefore has a large influence on

the change in slump with matrix content.

0

5

10

15

20

25

30

10 20 30 40 50 60 70

Matrix Content (%)

Lytag 0.3 w/c - modifiedslump prediction function

Mφrtsell dense aggregate slump prediction function - Lytag 0.3w/c

P r e d i c t e d S l u m p ( c m )

8/9/2019 be3942r05




The increase in workability with increasing matrix content may be considered as the interaction

between the aggregate and matrix components of the fresh concrete mix. A matrix dominated

system being full slump and aggregate dominated system being zero slump.

This investigation has highlighted that in lightweight concrete the change from aggregate to ma-trix domination of the slump with increase in matrix content is rapid compared to NDC. This

could well be due to the increased ability of the matrix phase to overcome inertia and cause

‘catastrophic’ movement of less dense aggregates. Figure 8 suggests that the start of slump oc-

curs at a larger matrix content in LWAC.

This may be due to the cohesive properties that the matrix imparts acting more significantly on

lighter aggregates, however there is little experimental evidence produced by this investigation

to either refute or support this hypothesis.

A full set of 28 day compressive strength and density measurements for the mixes produced in

this investigation are presented in Appendix C.

Figures 9 and 10 show strength / density relationships for Lytag and Liapor 8 aggregates. TheLiapor 8 aggregates displayed a more advantageous strength density relationship, especially

when used with an initially lower moisture state (as highlighted for 4 mixes in figure 10).

Examining the mix recipe data for these 4 mixes in Appendix D it can be seen that although a

substantially lower moisture content of existed in the Liapor aggregate the absorption properties

were not significantly different. This may have been caused by a moisture distribution through

the aggregate as shown in figure 11.

It should be noted that the Lytag aggregate used in this investigation is that which is supplied

for use on the UK market and is known to be different from that available on continental

Europe.

Maximum strengths achieved for these aggregates are not maximum possible values as the use

of silica fume and different aggregate/sand ratios are known to produce concrete compressive

strengths in excess of the values shown in figures 8 and 913

.

Figure 9 – Lytag Strength Density relationship for project mixes

1920

1930

1940

1950

1960

1970

1980

1990

2000

2010

2020

2030

2040

2050

50 55 60 65 70 75 80

Compressive Strength (MPa)

S a t u r a t e d 2 8 d a y D e n s i t y ( K g / C u . m

)

Strength / Density Trend line

Initial aggregate moisture content approx. 8%

8/9/2019 be3942r05


8/9/2019 be3942r05




6 CONCLUSIONSThe following specific conclusions have been drawn from the experimental studies de-

tailed in this report.

1. Typical UK Lightweight aggregates were found to attain a moisture content close to

their maximum moisture capacities, under typical pumping pressures (4.5 MPa).

2. The addition of a pumpaid to absorption water did not influence the amount of mois-

ture absorbed by lightweight aggregates. This suggests that the use of a pumpaid

could not be expected to influence the amount of absorption into lightweight aggre-

gates in pumped concrete.

3. The Punkii- method8 of assessing the quantity of moisture absorption of aggregates

was assessed as yielding results of large variability. The results attained suggested

little difference in the absorption by lightweight aggregate from a paste without and

containing pumpaid.

4. The ‘flowcyl’ method of paste characterisation was successfully used to view the in-

fluence of pumpaid and superplasticiser dose on the paste flow properties. 'Optimum'

levels of superplasticiser were selected for further work on the basis of this study.

5. The workability prediction functions developed by Mørtsell for normal weight con-crete were found not to be applicable to lightweight concrete. The workability of

lightweight concretes was found to change more rapidly with matrix content when

compared to normal weight aggregate concrete.

6. Modified functions for the prediction of workability of lightweight concrete are pro-

posed.

7. Liapor 8 produced concretes with a more advantageous strength / density relationship

than concrete made from UK Lytag.

8/9/2019 be3942r05




7 REFERENCES

(1) BS812: Part 2 (1975) ‘Aggregates - Methods of determination of physical prop-

erties’ British Standards Institution, London.

(2) BS 812: Part 109 (1990) ‘Methods for determination moisture content’, British

Standards Institution, London.

(3) BS 1881: part 108 (1983) ‘Method of making test cubes from fresh concrete.’

British Standards Institution, London.

(4) BS 1881: Part 102 (1983) ‘Method of determination of slump’ British Standards

Institution, London.

(5) BS 1881: Part 105 (1984) ‘Method of determination of flow’ British Standards


(6) BS 1881: Part 116 (1983) ‘Method of determination of compressive strength of

concrete cubes’ British Standards Institution, London.

(7) Ernst Mørtsell, Sverre Smeplass, Tor Arne Hammer, Magne Maage ‘Flowcyl - How to

determine the flow properties of the matrix phase of high performance concrete’ Proc4th International Symposium on utilisation of High Strength / High Performance con-

crete, 29 - 31 May 1996, Paris . Vol. 2. pp 261 - 268.

(8) Jouni Punkki, Odd E. Gjorv “Water absorption by high-strength lightweight

aggregate”, Proc. High Strength Concrete 1993, 20 - 24 June, Lillehammer,

Norway. pp 713 - 721.

(9) Personal communication with Mr. Andrew Turner, Putzmeister Ltd. (UK)

(10) Personal communication with Mr. Tim Cleverley, Lytag UK. June 17th, 1998.

(11) Ernst Mørtsell ‘Modellering AV Delmaterialenes betydningfor Betongens kon-

sistens’ PhD Thesis. 1996. Institutt for Konstruksjonsteknikk, Trondheim,

Norway. pp 301.

(12) BS 812 : Section 103.1: (1985) ‘Aggregate - Sieve Tests’, British Standards


(13) Nigg Gravity Base Project – Mix development trials carried out by Taywood

Engineering Ltd. for Taylor Woodrow Construction. 1998.

8/9/2019 be3942r05




8 NOMENCLATURELWA Lightweight aggregate

LWAC Lightweight aggregate concrete

NDA Normal density aggregate

NDC Normal density concrete

w/b water binder ratio

w/c water cement ratio

CEB Comité Euro-international du Béton

CEN Comité Européen de Normalisation

CTR Cost Time Resources (form)EN European Standard

FIB Féderation Internationale du Béton

FIP Féderation Internationale de la Précontrainte

MG Management Group

TC Technical Committee (CEN)

TG Task Group

TLG Task Leaders Group

8/9/2019 be3942r05




APPENDIX A

S-CURVE - AGGREGATE PARAMETER DETERMINATION

Stock san d 130367- T i l con 7 Oaks Quar r y

Sieve s ize Wg t . Reta in (g ) % Ret a in % Ret a in Cum .%

10 0 0 0.0 0.0 0.0

6.13 2.2 0.17

5 7.1 0.55 0.7 0.7 0.7

2.36 119.1 9.29 9.3 10.0 10.0

1.18 113.2 8.83 8.8 18.8 18.8

0.6 178 13.88 13.9 32.7 32.7

0.3 578.6 45.12 45.1 77.8 77.8

0.15 236.9 18.47

0.125 24.9 1.94 20.4 98.3 49.1

< 0.125 22.5 1.75 1.8Total 1282.5 100 189.3

Fineness Mod*. = 1.89255 150 ,300 ,600 ,1.18 mm, 2.36mm, 5.0mm sieves

*Modified to use 0.125 mm sieve instead of 0.150 mm sieve

Ly tag Samp le No . 130336

Si ev e s ize In i t ia l W gt (g ) i n al W g t (g ) g t. R et ai n (g ) % R et ai n % Ret ai n C um .%

10 438.8 738.6 299.8 34.4 34.4 34.4 34.4

6.13 471.1 1005.8 534.7 61.4

5 488.3 579.5 7.1 0.8 62.2 96.7 96.72.36 429.3 454.4 25.1 2.9 2.9 99.5 99.5

1.18 406 406.2 0.2 0.0 0.0 99.6 99.6

0.6 347 347.6 0.6 0.1 0.1 99.6 99.6

0.3 322.5 324.8 2.3 0.3 0.3 99.9 99.9

0.15 299.4 299.9 0.5 0.1

0.125 271.1 271.3 0.2 0.0 0.1 100.0 50.0

< 0.125 270.1 270.3 0.2 0.0 0.0

870.7 100.0 100.0 579.7

Fineness Mod*. = 5.80

*Modified to use 0.125 mm sieve instead of 0.150 mm sieve

L iapo re Samp le No . 130348

Si ev e s ize In i t ia l W gt (g ) i n al W g t (g ) g t. R et ai n (g ) % R et ai n % Ret ai n C um .%

10 438.8 438.8 0.0 0.0 0.0 0.0 0.0

6.13 471.2 620.3 149.1 49.7

5 488.4 871 7.1 2.4 52.0 52.0 52.0

2.36 429.2 572.9 143.7 47.9 47.9 99.9 99.9

1.18 406 406 0.0 0.0 0.0 99.9 99.9

0.6 346.8 346.8 0.0 0.0 0.0 99.9 99.9

0.3 322.6 322.7 0.1 0.0 0.0 99.9 99.9

0.15 299.4 299.6 0.2 0.1

0.125 271.4 271.4 0.0 0.0 0.1 100.0 50.0

< 0.125 270.3 270.3 0.0 0.0 0.0

300.2 100.0 100.0 551.7 501.7

Fineness Mod*. = 5.02

8/9/2019 be3942r05




Measured Particle Density (Saturated Surface Dry)

Sand 2.5744 (2574 Kg/cu.m)

Lytag 4 -12 mm 1.6827 (1683 Kg/cu.m)

Liapor 8 : 4 - 8 mm 1.7377 (1738 Kg/cu.m)

Measured Uncomp acted Bulk dens i ty

Sand 1412.88 (Kg/Cu.m) Moisture content = 4.0%

Lytag 4 -12 mm 887.69 (Kg/Cu.m) Moisture content = 11.4%

Liapor 8 : 4 - 8 mm 984.47 (Kg/Cu.m) Moisture content = 17.1%

All materials tested as recieved

Calculation of Hs Values for S-Curves

Aggregate Type Lytag 4 - 12 mm Aggregate Type Liapor 8 : 4- 8 mm

Volume of Sand (Vs) 0.4 Volume of Sand (Vs) 0.4

Volume of Agg (Va) 0.6 Volume of Agg (Va) 0.6

Air Voids Ratio Sand (Hs) 0.4512 Air Voids Ratio Sand (Hs) 0.4512

Air Volids Ratio Agg (Hp) 0.4725 Air Voids Ratio Agg (Hp) 0.4335

Fineness Modulus Sand (Fms) 1.89 Fineness Modulus Sand (Fms) 1.89

Fineness Modulus Agg (Fmp) 5.8 Fineness Modulus Agg (Fmp) 5.02

Agg Parameter Sand (Ts) 9 Agg Parameter Sand (Ts) 9

Agg Parameter Agg (Tp) 8 Agg Parameter Agg (Tp) 8

Hm = 8.65 Hm = 8.65

8/9/2019 be3942r05




APPENDIX B

S-CURVES FOR CONCRETES INVESTIGATED

LWA c onc rete - wo rkabi l i ty predic t ion g raph

Taywood Engineering Ltd. - Eurolightcon Project - Task 3

1 λ Q = 0.92 Mix Constituents :

2 Hm = 8.65 Superplasticiser (Sample No. 130263) Content (%) = 2.25 %

3 m -Slump = 0.00 7 Oaks Sand' - Sample No. 130367

4 n -Slump = 28.40 Liapor Aggregate - Sample No. 130348

5 m -Spread = 30.00 Class 42.5 Portland Cement - Stock No 1303776 n -Spread = 70.00 Slump prediction function 115*EXP(-2.225*lQ)

7 α-Slump = 14.85 Trial Matrix (Fp ) Slum S read 28 day Strength 28 Day Density

8 β-Slump = -0.40 Mix No. (volume %) (cm) (cm) (MPa) (Kg/cu.m)

9 α-S read = 14.85 15 30 23 45.5 75 2025

10 β-Spread = -0.39 18 35 27.5 60.7 73.5 2010

11 Fpn-Sl i % = 33.51 33 28 20 40 77.5 2025

12 F n-S i % = 34.11 40 26 1.5 30 72 1945

13 F m-Sl i % = 26.77 41 27 1 30 73.5 1950

14 Fpm-Sp i % = 27.37

L i apor 8 : 4 -8 mm - 0.25 w /c

0

10

20

30

40

50

60

70

20 25 30 35 40

Fp = Volume % matrix

K p = S l u m p a n d S p r e a d ( c m ) Slump

Kp_Sl

Kt_Sl

Spread

Kp_Sp

Kt_Sp

40

40 41

41

1533

15

33

18

18

8/9/2019 be3942r05


8/9/2019 be3942r05




2020

20

31

17

17

39

39

31

LWA conc rete - wo rkabi l i ty predict ion graph





4 n -Slump = 28.40 Lytag Aggregate - Sample No. 130336

5 m -Spread = 30.00 Class 42.5 Portland Cement - Stock No 130377

6 n -Spread = 70.00 Slump prediction function 115*EXP(-2.225*lQ)

7 α-Slump = 14.85 Trial Mix Matrix (Fp ) Slump Spread 28 Day Strength 28 Day Density

8 β-Slump = -0.40 No. (volume %) (cm) (cm) (MPa) (Kg/cu.m)

9 α-Spread = 14.85 10 30 10 32 64.5 2015

10 β-Spread = -0.39 13 35 8 35 64.5 2005

11 Fpn-Sl i % = 33.51 36 32 21 58 57 2015

12 Fpn-Sp i % = 34.11 35 28 4 30 59 1995

13 Fpm-Sl i % = 26.77 43 35 28.4 63 62 2015

14 Fpm-Sp i % = 27.37

P3054År20AIII

0

10

20

30

40

50

60

70

20 25 30 35 40 45 50


K p = S l u m p a n d S p r e a d ( c m

Slump

Kp_Sl

Kt_Sl

Spread

Kp_Sp

Kt_Sp

Ly t ag 4 -12 mm - 0.25 w /c

0

10

20

30

40

50

60

70

20 22 24 26 28 30 32 34 36 38 40


K p =

S l u m p a n d S p r e a d ( c m

Slump

Kp_Sl

Kt_Sl

Spread

Kp_Sp

Kt_Sp

Erroneous Result

Erroneous Result

35

10

10

36

36

13

1335

43

43

8/9/2019 be3942r05




LWA con crete - wo rkabi l i ty predict ion g raph








7 α-Slump = 20.73 Trial Mix Matrix (Fp ) Slump Spread 28 day Strength 28 Day Density


9 α-Spread = 20.73 8 30 24.5 56.3 54.5 1955

10 β-S read = -0.40 26 32 26 62.5 57.5 1970

11 Fpn-Sl i % = 31.59 25 28 10 34.5 60 1975

12 Fpn-Sp i % = 32.19 27 26 5 30 57 1960

13 Fpm-Sl i % = 26.77 28 29 18 45.5 61 1995

14 Fpm-Sp i % = 27.37 29 24 2.5 30 58.5 1965

Ly t ag 4 - 12 mm - 0.30 w /c

0

10

20

30

40

50

60

70

20 22 24 26 28 30 32 34 36 38 40


K p =

S l u

m p a n d S p r e a d ( c m

Slump

Kp_Sl

Kt_Sl

Spread

Kp_SpKt_Sp

26

27

27

25

25

28

28

8

8

26

8/9/2019 be3942r05




LWA concrete - wo rkabi l i ty predic t ion g raph








7 α-Slum = 29.60 Trial Mix Matrix (Fp ) Slump Spread 28 day Strength 28 Day Density


9 α-Spread = 29.60 11 30 12.5 39 51.5 194010 β-S read = -0.42 14 25 0.5 30 52 1945

11 Fpn-Sl i % = 30.15 37 32 20.5 37 51.5 1940

12 F n-S i % = 30.75 38 29 15 36 51.5 1950

13 Fpm-Sl i % = 26.77

14 Fpm-Sp i % = 27.37

Lyt ag 4 -12 mm - 0.35 w /c

0

10

20

30

40

50

60

70

20 22 24 26 28 30 32 34 36 38 40


K p = S l u m p a n d S p r e a d ( c m )

Slump

Kp_Sl

Kt_Sl

Spread

Kp_Sp

Kt_Sp14

14

38

3811

11

37

37

8/9/2019 be3942r05




APPENDIX C

28 DAY COMPRESSIVE STRENGTH, WORKABILITY AND

DENSITY DATA

Mix No. w/c matrix Lgtwgt

Aggregate

Slump

(mm)

Flow

(mm)

Demould Density

(Kg/ cu.m)

Density @ 28

days (Kg/ cu.m)

Comp Stren

(MPa)

10 0.25 30 Lytag 100 320 - 2013 64.5

11 0.35 30 Lytag 125 390 - 1940 51.7

12 0.3 25 Lytag 0 min - 1937 54.5

13 0.25 35 Lytag 80 350 - 2007 64.7

14 0.35 25 Lytag 5 min - 1947 52.2

25 0.3 28 Lytag 100 345 1970 1977 60

26 0.3 32 Lytag 260 625 1973 1970 57.3

27 0.3 26 Lytag 50 300 1965 1960 57.228 0.3 29 Lytag 180 455 1998 1993 61

29 0.3 24 Lytag 25 260 1965 1963 58.5

35 0.25 28 Lytag 40 min 1988 1995 59

36 0.25 32 Lytag 210 580 1991 2015 57

37 0.35 32 Lytag 205 370 1927 1940 51.5

38 0.35 29 Lytag 150 360 1936 1950 51.5

43 0.25 35 Lytag 284 630 - 2015 62

15 0.25 30 Liapor 230 455 - 2027 75.2

16 0.3 30 Liapor 230 520 - 1987 65

17 0.35 30 Liapor 160 420 - 1983 60.5

18 0.25 35 Liapor 275 610 - 2010 73.719 0.3 25 Liapor 5 min - 2000 67.8

20 0.35 25 Liapor 10 min - 1977 61.3

31 0.35 28 Liapor 80 370 1999 2003 67.8

32 0.3 29 Liapor 230 530 1994 1997 67.7

33 0.25 28 Liapor 200 400 2028 2026 77.3

34 0.3 28 Liapor 180 425 2009 2000 69

39 0.35 31 Liapor 235 650 1940 1950 63

40 0.25 26 Liapor 15 min 1944 1943 72

41 0.25 27 Liapor 10 min 1946 1950 73.5

42 0.3 27 Liapor 115 430 1949 1950 68.5

43 0.25 35 Lytag 284 630 - 2015 62

8/9/2019 be3942r05



APPENDIX D

MIX RECIPES

Mix DetailsMix Lightweight Matrix Nominal Mix Moisture content Absorption

No. Aggregate (%) w/c Volume sand LWA sand LWA

(cu.m) % % % %

8 Lytag 30 0.3 0.035 3.08 11.42 -1.06 7.0410 Lytag 30 0.25 0.035 4.00 7.57 -1.98 5.9411 Lytag 30 0.35 0.035 4.00 7.57 -1.98 5.9413 Lytag 35 0.25 0.035 4.00 7.57 -1.98 5.9414 L ta 25 0.35 0.035 4.00 7.57 -1.98 5.94

15 Liapor 8 30 0.25 0.035 4.00 20.48 -1.80 0.8716 Liapor 8 30 0.3 0.035 4.00 20.48 -1.80 0.87

17 Liapor 8 30 0.35 0.035 4.00 20.48 -1.80 0.8718 Liapor 8 35 0.25 0.035 4.00 20.48 -1.80 0.8719 Liapor 8 25 0.3 0.035 4.00 20.48 -1.80 0.8720 Liapor 8 25 0.35 0.035 4.00 20.48 -1.80 0.87

25 L ta 28 0.3 0.035 4.90 7.22 -2.70 6.7826 L ta 32 0.3 0.035 4.90 7.22 -2.70 6.7827 Lytag 26 0.3 0.035 4.90 7.22 -2.70 6.7828 Lytag 29 0.3 0.035 4.90 7.22 -2.70 6.7829 Lytag 24 0.3 0.035 4.90 7.22 -2.70 6.78

31 Liapor 8 28 0.35 0.035 6.08 20.39 -3.88 0.64

32 Lia or 8 29 0.3 0.035 6.08 20.39 -3.88 0.6433 Lia or 8 28 0.25 0.035 6.08 20.39 -3.88 0.6434 Lia or 8 28 0.3 0.035 6.08 20.39 -3.88 0.64

35 Lytag 28 0.25 0.035 2.60 9.40 -0.40 5.8036 Lytag 32 0.25 0.035 2.60 9.40 -0.40 5.8037 Lytag 32 0.35 0.035 2.60 8.30 -0.40 6.8038 Lytag 29 0.35 0.035 2.60 8.30 -0.40 6.80

39 Lia or 8 31 0.35 0.035 2.60 10.30 -0.40 0.4040 Lia or 8 26 0.25 0.035 2.60 10.30 -0.40 0.4041 Liapor 8 27 0.25 0.035 2.60 10.30 -0.40 0.4042 Liapor 8 27 0.3 0.035 2.60 10.30 -0.40 0.40

43 Lytag 35 0.25 0.035 1.96 10.64 0.24 5.00

Negative figure for absorption denotes water inexcess of SSD conditionLWA absorption values were measured (30 mins) for each set of mixesThe sand absorption value was calculated by measuring the actual moisture content and

subtracting the moisture content for SSD condition.

be3942r05

Documents