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Energy and Buildings 68 (2014) 541–546

Contents lists available at ScienceDirect

Energy and Buildings

j ourna l ho me page: www.elsev ier .com/ locate /enbui ld

ow embodied energy cement stabilised rammed earth building—Aase study

.V. Venkatarama Reddya,∗, Georg Leuzingerb, V.S. Sreeramc

Department of Civil Engineering, Indian Institute of Science Bangalore, IndiaL&S Architects, Bangalore, India746, 10th Main, Basaveswaranagara 3rd Stage, 3rd Block, Bangalore, India

r t i c l e i n f o

rticle history:eceived 17 May 2013eceived in revised form0 September 2013ccepted 30 September 2013

a b s t r a c t

Rammed earth is a monolithic construction and the construction process involves compaction of pro-cessed soil in progressive layers in a rigid formwork. Durable and thinner load bearing walls can be builtusing stabilised rammed earth. Use of inorganic additives such as cement for rammed earth walls hasbeen in practice since the last 5–6 decades and cement stabilised rammed earth (CSRE) buildings can be

eywords:ammed earthement stabilisationtabilised soil

seen across the world. The paper deals with the construction aspects, structural design and embodiedenergy analysis of a three storey load bearing school building complex. The CSRE school complex consistsof 15 classrooms, an open air theatre and a service block. The complex has a built-up area of 1691.3 m2

and was constructed employing manual construction techniques. This case study shows low embodiedenergy of 1.15 GJ/m2 for the CSRE building as against 3–4 GJ/m2 for conventional burnt clay brick load

s.

mbodied energy bearing masonry building

. Introduction

Rammed earth is used for the construction of load bearing walls.ammed earth walls are built by compacting processed soil in pro-ressive layers in a rigid formwork. Rammed earth constructionsan be broadly grouped into two categories: stabilised rammedarth and un-stabilised rammed earth. The basic materials usedor the construction of unstabilised rammed earth are soil, sandnd gravel, while stabilised rammed earth uses stabilisers (cement,ime, etc.) in addition to soil, sand and gravel. Strength (in sat-rated state) and erosion due to rain impact are a concern fornstabilised rammed earth buildings. These concerns can be effec-ively addressed by using cement stabilised rammed earth. Portlandement is being used for rammed earth wall construction sincehe last 5–6 decades. Examples of cement stabilised rammed earthCSRE) buildings can be seen across the world [1–4]. Low embod-ed carbon, seamless wall surface, scope for adjusting the surfaceexture and colour, and flexibility in wall thickness and plan formepresent some of the major advantages of rammed earth construc-ion. There is a growing interest among the building professionals

o use CSRE walls for structural applications especially for the loadearing walls in the buildings.

∗ Corresponding author. Tel.: +91 080 2293 3126; fax: +91 80 23600404.E-mail addresses: venkat@civil.iisc.ernet.in (B.V. Venkatarama Reddy),

sarchitecture@gmail.com (G. Leuzinger), srinand28@yahoo.com (V.S. Sreeram).

378-7788/$ – see front matter © 2013 Elsevier B.V. All rights reserved.ttp://dx.doi.org/10.1016/j.enbuild.2013.09.051

© 2013 Elsevier B.V. All rights reserved.

There are limited investigations addressing the issues ofstrength and stability of CSRE walls [1,2,5–8]. Focused studies espe-cially on the structural behaviour of CSRE walls are limited. Detailedinvestigations of Kumar [9], and Reddy and Kumar [10–13] throwmore light on the behaviour of CSRE walls under compression.Walker et al. [4] attempted to give design guidelines for rammedearth walls based on the principles of masonry wall behaviour.

Proper design codes for designing multi-storey load bearing sta-bilised rammed earth buildings are not available. There is limitedknowledge on the structural behaviour of storey height walls. Basedon the results of few investigations [4,5,10–13] on strength and sta-bility of stabilised rammed earth walls a three storey load bearingrammed earth school complex was designed and constructed atBangalore. Bangalore is situated at 12◦58′ N and 77◦38′ E in India.The building was constructed in the year 2009. Mean annual mini-mum and maximum temperatures in Bangalore are 15 ◦C and 35 ◦C,respectively. Mean annual minimum and maximum temperaturesin winter are 15 ◦C and 28 ◦C, respectively. There is no space con-ditioning in any part of the building complex for controlling theindoor climate.

The present investigation pertains to a case study illustratingthe design, construction and EE analysis of a three storey high andload bearing CSRE school building complex. The study is focusedon (1) demonstrating a structural design approach for load bearing

stabilised rammed earth walls, (2) presenting construction detailsand quality control aspects where the construction was managedmainly by manual processes, and (3) analysis of embodied energy ofthe three storey load bearing school building complex. The present

542 B.V. Venkatarama Reddy et al. / Energy and Buildings 68 (2014) 541–546

tions

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The floor slabs consist of composite beam and masonry jack-arch system as illustrated in section-BB of Fig. 1. The masonryjack-arch was constructed using a slip form formwork. Stabilisedsoil block masonry in cement–soil mortar was used for masonry

Fig. 1. Typical floor plan and sec

tudy assumes importance because there are limited number ofnvestigations concerning the design and embodied energy aspectsf large span and multi-storey load bearing CSRE structures.

. Details of the school building complex

This is a government run public school catering to the studentsursuing primary and higher secondary education. There are about000 students studying in this school. Typical floor plan and theections of the three storey school building complex are illustratedn Fig. 1. There are five classrooms 7.0 m × 7.5 m (clear dimensions)n each floor. Apart from the 15 classrooms, there is a commonong corridor in each floor, double storey heigh stage/theatre hallnd a service block. The total built-up area of the school complex is691.3 m2. Fig. 2 shows a view of the three storey school buildingomplex.

. Technical specifications

Brief specifications of various components of the building are asollows.

.1. Foundation and plinth

The foundation consists of spread footing built using size stoneasonry in cement mortar. There is a continuous 100 mm thick

einforced concrete plinth beam with nominal reinforcement.

.2. Walls and supporting structure

Load bearing CSRE walls have 8% ordinary Portland cement (byeight) as stabiliser. The main load bearing walls are the centralalls; 400 mm thick in the ground floor, 350 mm in the first floor

of the school building complex.

and 300 mm in the second floor as illustrated in section-AA of Fig. 1.The walls supporting the corridor slab and other walls are 250 mmthick. There are few reinforced concrete columns in the corridorand stage area. The columns in the corridor portions were providedmainly to drain-off the rain water from the roof through the pipesembedded in them.

3.3. Floor and roofing system

Fig. 2. View of the CSRE school complex.

B.V. Venkatarama Reddy et al. / Energy and Buildings 68 (2014) 541–546 543

0

20

40

60

80

100

1010.10.010.001

% F

iner

Natural soilReconstituted soil

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Particle size (mm)

Fig. 3. Grain size distribution curves.

ack-arch construction. The roof consists of reinforced concreteeam and slab construction. Stabilised soil block filler slab sys-em has been used in the corridors. Concrete having characteristicompressive strength of 20 MPa was used for all the concrete works.

.4. Flooring, openings and other features

Flooring consists of plain concrete padding with cement mor-ar topping. The doors and windows have metal frame and metalhutters. There are continuous sill and lintel bands as earthquakeesistant features. The Bangalore city falls under a low earthquakentensity zone and the Indian code suggests use of continuous lintelnd sill bands as earthquake resistant features.

. Construction methodology

This case study demonstrates the construction of a three storeyigh load bearing CSRE building with fairly large spans of about

m. This building demonstrates that thinner load bearing walls300–400 mm) can be used for larger spans and three storey highuildings. Construction details of the building are discussed in theollowing sections.

.1. Cement stabilised rammed earth walls

Earlier studies suggest that coarse grained soils with less-xpansive clay minerals (such as kaolinite, illite, etc.) are best suitedor cement stabilised soil blocks. The studies suggest that about 15%lay in the soil yields best results [14–16]. Detailed investigations ofeddy and Kumar [11,12] on CSRE revealed that the optimum clayontent is about 15% and the density plays a crucial role in con-rolling the strength of CSRE. Considering the recommendations ofhe above mentioned investigations the clay content of a local soilas adjusted to optimum level by diluting with sand. A local soilith 26% clay fraction was reconstituted by diluting with sand in

he proportion of 1:1 (soil:sand, by weight). The reconstituted soilontained 13% clay fraction. Fig. 3 shows the grain size distributionurves for the natural soil and the reconstituted soil. Compactionharacteristics of soil can be standardised with reference to stan-ard Proctor test. This test involves compaction of partly saturatedoil in a cylindrical mould with a fixed compaction energy inputnd then obtaining a relationship between density and moistureontent. Indian standard code [17] guidelines were followed to per-orm this test. Standard Proctor optimum moisture content (OMC)nd maximum dry density for the reconstituted soil mixture con-

aining 8% cement are 12.5% and 1900 kg/m3, respectively. Eightercent (by weight) ordinary Portland cement was used as a sta-iliser. Details of the construction procedure adopted for rammedarth wall construction are as follows.

Fig. 4. Long and continuous wooden formwork.

(i) Soil, sand and cement were mixed in a rotary drum mixer for10 min. Mixing duration of 10 min ensured uniform mixing ofall the ingredients. The dry mixture was then spread into a thinlayer and then a known quantity of water was sprinkled on it,and the mixing was carried out manually such that there isuniform distribution of water in the mix. The quantity of wateradded was calculated based on the Proctor OMC (12.5%).

(ii) The partially saturated mix was weighed and then poured intothe wooden formwork. Using metal rammers the mix wasrammed such that a uniform layer of 100 mm thickness wasobtained. The quantity of the mix fed into the mould and thethickness of the compacted layer were monitored in order toensure a dry density of 1800 kg/m3. After completion of onelayer the surface was dented using a round headed rammerand then the second layer was compacted immediately. Theprocess of compacting the soil–cement mix in layers was con-tinued till to a height of 900 mm.

iii) The shuttering was dismantled after two days of casting andthen curing was continued for 4 weeks. Fig. 4 shows longwooden formwork and the rammed earth wall surface. Tongueand groove type construction joints were introduced at every2.5 m interval.

(iv) Rammed earth prisms of size 150 mm × 150 mm × 300 mmwere cast at the construction site. The prisms were madefrom the same mix that went into the rammed earth wallsand using metal moulds. The prisms were cast by ramming(using flat headed rammer) the mix in three layers of 100 mmeach. The quantity of material going into each compacted layerof 100 mm was controlled to ensure 1800 kg/m3 dry densityfor the prism. After completion of each layer the surface wasdented using a round headed rammer before the next layerwas compacted. The mould was dismantled after 48 h of cast-ing and the compacted rammed earth prism was wrapped withburlap. The curing of the burlap wrapped prisms was carriedout at the construction site by spraying water and ensured thatthe prism is moist. After 28 days curing the prisms were soakedin water for 48 hours and then tested (in the laboratory in adisplacement controlled universal testing machine) for com-pressive strength. Soaking in water for 48 h ensures that theprism is in saturated condition. The mean unconfined compres-sive strength (in saturated state) of the prisms (eight numbers)was 4.18 MPa with a standard deviation of 0.59 MPa.

4.2. Composite masonry jack-arch floor

Cross section of the composite masonry jack-arch floor systemis shown in Fig. 1 (Section-BB). The reinforced concrete beam was

544 B.V. Venkatarama Reddy et al. / Energy and Buildings 68 (2014) 541–546

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Table 1Specific energy consumption in building materials (Praseeda [19]).

Type of material Unit Energy (MJ/unit)

1. Cement tonne 36002. Steel tonne 32,0003. Coarse aggregates m3 125.44. Fine aggregates m3 52.5

Fig. 5. Ceiling view of stabilised soil block filler slab floor.

artially cast and then the masonry jack arch was constructed usinglip form moulds. On top of the jack-arch screed concrete waspread keeping a minimum thickness of 25 mm at the crown ofhe arch. The screed concrete contains minimum reinforcement toake care of shrinkage stresses.

.3. Filler slab floor and roof in the corridors

The corridors were provided with a stabilised soil block fillerlab roof. Fig. 5 shows the ceiling view of the filler slab roof/floor.he filler blocks were positioned in between the reinforcement barsnd then concrete was placed without disturbing the positions ofller blocks. The filler blocks replaced about 28% of the concreteolume.

. Structural design of cement stabilised rammed earthalls

The design guidance development for CSRE walls is still in theascent stage. Especially information on the stability and behaviourf CSRE walls under eccentric loads does not exist. There is no reli-ble information on the stress reduction factors for CSRE walls.nvestigations on developing design guidance for multi-storeyedoad bearing CSRE walls and buildings are limited. With the limitednformation on design of CSRE walls, the design calculations for ahree storey load bearing CSRE wall are shown below.

The most critical wall in the building complex is the central wallFig. 1, section-AA) supporting the roof/floor slabs. Let us considerhe ground floor middle wall, which is a 400 mm thick solid wall.he floor slabs span on either side of the wall in the adjoining rooms.ndian code [18] specifies admissible live loads for designing floorlabs of school buildings. Based on the code [18] guidelines a liveoad of 5 kN/m2 was considered in arriving at the design loads onhe central wall of the building.

Consider 1.0 m length of the ground floor middle wallFactored loads realised on this wall = 477 kN per metre length;(load factor = 1.5)Design compressive stress = 1.193 MPa and slendernessratio = 5.63 (partial restrained end conditions)Mean unconfined compressive strength of CSRE = fa = 4.18 MPa;standard deviation = � = 0.59 MPa

Characteristic unconfined material compressivestrength = fc = fa − 1.65� = 3.2 MPaEccentricity = 0, since it is a middle wall having equal floor spanson either side

5. Size stones m3 52.5

Capacity reduction factor (ϕ) for slenderness ratio and eccentricity[4] = 1

Nd ≤ �fcbt

�m

where Nd = design compressive force; ϕ = capacity reduction fac-tor; b = breadth of the wall; T = wall thickness; fc = characteristicunconfined material compressive strength and �m = material par-tial safety factor.

�fcbt

�m= 512 kN

where ϕ = 1; fc = 3.2 MPa; b = 1000 mm; t = 400 mm and �m = 2.5. �m

is taken as 2.5 since the rammed earth prisms were made at sitefrom the same mix and achieving same density as in the wall.

Design compressive force = Nd = 477 kNTherefore, Nd < (�fcbt)/�m, the design is safeGlobal factor of safety in the wall design = (load factor) × (partialfactor of safety) = 1.5 × 2.5 = 3.75

6. Analysis of embodied energy

Embodied energy (EE) analysis of a fairly large load bearing CSREbuilding has been shown in this section. EE values of the differ-ent alternative building components as well as the whole CSREbuilding have been compared with the corresponding EE valuesof conventional structures.

Assessing the embodied energy of a building requires specificenergy consumption values for the basic construction materials.Table 1 gives the specific energy consumption values of the buildingmaterials used in the construction. It has been mentioned in the ref-erence [19] that the specific energy values of the basic materials (inTable 1) were generated based on the actual industrial survey datausing process analysis principles. EE values from the reference [19]closely represent the data from Indian construction industry andhence they were used in the present study. Explaining the methodsand processes of estimating EE values of basic construction materi-als is outside the scope of the present study. Considering the specificenergy values given in Table 1, EE values for various components(such as cement concrete, CSRE, masonry, reinforced concrete slab,filer slab, etc.) of the building were calculated. Assessing EE val-ues of some of the building components has been discussed in thefollowing sections.

6.1. Embodied energy of cement stabilised rammed earth wall

EE of CSRE wall greatly depends upon the specific energyconsumption of Portland cement apart from the energy due totransportation of materials and the energy spent in processing of

materials at the construction site. Mixing of soil, sand and cementin dry state was carried out using a drum type diesel engine oper-ated mixer. Mixing of water in the dry mix as well as compactionof the CSRE wall was carried out manually. The animate energy

B.V. Venkatarama Reddy et al. / Energy and Buildings 68 (2014) 541–546 545

Table 2EE of jack-arch masonry floor system and filler slab floor.

Details of materials Quantity for 1 m2 of flooring system Unit Energy coefficient EE (MJ)

(A) Jack-arch masonry floor system(1) Cement stabilised soil block masonry in arches 0.136 m3 659.5 89.69(2) Concrete including mixing energy 0.233 m3 1726 402.16(3) Reinforcement 18.63 kg 32 596.16

EE/m2 of jack-arch masonry floor system 1088.00(B) Reinforced concrete filler slab floor(1) Cement stabilised soil blocks 0.036 m3 500 18.00

m3 1726 155.34kg 32 176.00

filler slab floor 349.34

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Walls, columns, etc

21%

Openings4%

Misc6%

Floors/roof54%

Foundation15%

Fig. 6. EE share among various components of the building.

Concrete29.4%

Steel48.8%

Stone masonry

7.3%

Flooring & Finishes

4.1%

Misc.2.2%

CSRE & SSB Walls8.2%

(2) Concrete including mixing energy 0.090(3) Reinforcement 5.50

EE/m2 of reinforced concrete

nvolved in these operations has not been included in the EE calcu-ations. With 8% Portland cement in the wall and energy content of1.9 MJ/kg for diesel the total EE of CSRE wall is 517 MJ/m3. Moreetailed discussion on EE in CSRE walls can be found in the studiesf Reddy and Kumar [20].

.2. Embodied energy of jack-arch masonry floor system

Dimensioned cross section of composite jack-arch masonryoor system used in the classroom floors of the school building

s shown in Fig. 1 (section BB). The floor system consists of sta-ilised soil block masonry, concrete, cement–soil mortar and steeleinforcement. The entire assembly of the roofing system was car-ied out manually except that a diesel operated concrete mixer wasmployed for mixing the concrete. EE calculation of this type of floorystem is illustrated in Table 2. EE of composite masonry jack-archoor system used in the building is 1088 MJ/m2. It should be notedere that the effective span of the jack-arch floor system is fairly

arge at 7.9 m.

.3. Reinforced concrete filler slab floor

A portion of the material below neutral axis in a reinforced con-rete solid slab can be replaced by a filler material such as cementtabilised soil block (CSSB). Fig. 5 shows the ceiling of a CSSB fillerlab floor system. The volume of CSSB filler material in this floorystem is 28%. Table 2 gives details of EE calculations for the fillerlab roof. There is a considerable difference in the EE of CSSB andoncrete, which has resulted in 12% reduction in CSSB filler slaboor when compared with EE of solid concrete slab floor. The totalmbodied energy of filler slab floor system is 350 MJ/m2 of the slab.he corridor floor slabs have a span of 2.85 m.

.4. Embodied energy of the whole school building complex

EE of the whole building complex was obtained by consider-ng the actual quantities of materials and the energy spent at siten the construction process. The EE of various components of theuilding was calculated considering the EE values of basic materialsiven in Table 1. Table 3 gives details of EE for various componentsf the building. EE of floor/roofing system, load bearing rammedarth walling and foundation is 1036 GJ, 410 GJ and 299 GJ, respec-ively. Total EE of the building works out to 1948 GJ for the totaluilt-up area of 1691.3 m2. Share of EE among various componentsf the building is illustrated as pie chart in Fig. 6. The floor and rooflabs consume more than half of the EE of the building. EE con-umed by the rammed earth walls and other supporting structures about 21%. The miscellaneous items include staircase, weather

roof coarse, meshwork plaster, etc. Fig. 7 shows the break up ofE among different materials used in the construction. Lion’s share49%) of the EE is in the steel consumed for the building construc-ion. EE of concrete constitutes about 29% of total EE. EE of Steel

Fig. 7. EE share among various materials used in the building.

and concrete (energy intensive materials) together constitute 78%of total EE of the building. The EE of CSRE and CSSB walls is just 8%of the total EE of the building.

EE of the CSRE school building is 1.15 MJ/m2. The EE values of

load bearing brickwork building and a reinforced concrete framedstructure building are in the range of 3–4 GJ/m2 and 4.5–9 GJ/m2,respectively [19,21]. EE of the CSRE building is about one-third the

546 B.V. Venkatarama Reddy et al. / Energy and Buildings 68 (2014) 541–546

Table 3Embodied energy of the building complex (built-up area of the building = 1691.3 m2).

Building component Specifications Embodied energy (GJ)

1. Foundation Stone masonry and reinforced concrete plinth beam 2992. Walls and columns Rammed earth walls, stabilised soil block masonry, reinforced concrete (R.C.) columns, lintel and sill bands 4103. Floors and roof slabs Composite jack-arch masonry floors, R.C. filler slab and R.C. beams and slabs 10364. Openings Steel frame door and windows with steel mesh work and sheet metal leaves, steel ventilators 82

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5. Miscellaneous items Stair case, chajjas, floor and wall finishes, painting, g

Total embodied energy of the bu

E of load bearing brickwork building and is less than one fourth theE of reinforced concrete frame structure building. Considerablemount of EE can be saved by the use of CSRE and other alternativeuilding concepts.

The case study clearly demonstrates that there is scope foreducing EE of buildings by adopting rammed earth construction.he study assumes significance in the context of promoting greenuildings leading to energy and carbon emission reduction, andemonstrates the scope for carbon mitigation options in the con-truction sector.

. Concluding remarks

Design, construction and embodied energy consumption of ahree storey rammed earth load bearing school complex buildingas discussed. The construction of this structure demonstrated these of wooden formwork for the long cement stabilised rammedarth walls and methods of controlling the mix proportion and den-ity to achieve the design strength. A design methodology for CSREalls under gravity loads was demonstrated using the limit stateesign principles. An analysis of the embodied energy revealed thathe EE of CSRE building is 1.15 GJ/m2, which is considerably lesshen compared with EE of conventional burnt clay brick build-

ng (3–4 GJ/m2) and reinforced concrete framed structure building4–10 GJ/m2). The case study demonstrated the scope for reducinghe carbon emissions in the construction sector through the usef low EE materials such as CSRE walls and alternative floor/roofystems.

cknowledgements

Ms. Almitra Patel generously donated the entire cost of thechool project. Without the generous contributions of Ms. Almi-ra Patel the school building project would not have taken root.er concern for the education of deprived children and generousonations are gratefully acknowledged.

eferences

[1] P.L. Verma, S.R. Mehra, Use of soil–cement in house construction in the Punjab,Indian Concrete Journal 24 (1950) 91–96.

[

[

, meshwork, waterproofing, etc. 121

1948

[2] D. Easton, The Rammed Earth Experience, 1st ed., Blue Mountain Press,Wilseyville, CA, USA, 1982.

[3] M. Hall, Rammed earth: traditional methods, modern techniques, sustainablefuture, Building Engineer 77 (11) (2002) 22–24.

[4] P. Walker, R. Keable, J. Martin, V. Maniatidis, Rammed Earth Design and Con-struction Guidelines, BRE Bookshop, Watford UK, 2005.

[5] B. King, Buildings of Earth and Straw – Structural Design for Rammed Earth andStraw Bale Architecture, Ecological Design Press, Sausalito, 1996.

[6] M. Hall, P. Damms, Y. Djerbib, Stabilised rammed earth and the building regu-lations 2000. Part A. Structural stability, Building Engineer 79 (6) (2004) 18–21.

[7] M. Hall, Assessing the environmental performance of stabilised rammed earthwalls using a climatic simulation chamber, Building & Environment 42 (1)(2007) 139–145.

[8] C. Jayasinghe, N. Kamaladasa, Compressive strength characteristics of cementstabilised rammed earth walls, Construction & Building Materials 21 (2007)1971–1976.

[9] P. Prasanna Kumar, Stabilised Rammed Earth for Walls: Materials, CompressiveStrength and Elastic Properties, Ph.D. Thesis. Department of Civil Engineering,Indian Institute of Science, Bangalore, India, 2009.

10] B.V. Venkatarama Reddy, P. Prasanna Kumar, Compressive strength and elasticproperties of stabilized rammed earth and masonry, Masonry International 22(2) (2009) 39–46.

11] B.V. Venkatarama Reddy, P. Prasanna Kumar, Structural behaviour of story highcement stabilised rammed earth walls under compression, Journal of Materialsin Civil Engineering 23 (3) (2011) 240–247.

12] B.V. Venkatarama Reddy, P. Prasanna Kumar, Cement stabilised rammed earth.Part A. Compaction characteristics and physical properties of compactedcement stabilised soils, Materials and Structures 44 (3) (2011) 681–694.

13] B.V. Venkatarama Reddy, P. Prasanna Kumar, Cement stabilised rammed earth.Part B. Compressive strength and elastic properties, Materials and Structures44 (3) (2011) 695–707.

14] P. Walker, T. Stace, Properties of some cement stabilized compressed earthblocks and mortars, Materials and Structures 30 (1997) 545–551.

15] B.V. Venkatarama Reddy, P. Walker, Stabilised mud blocks: problems andprospects, in: Proc. Int. Earth Building Conf., Earth Build 2005, Sydney, Australia,2005, pp. 63–75.

16] B.V. Venkatarama Reddy, R. Lal, K.S. Nanjunda Rao, Optimum soil grading forthe soil–cement blocks, Journal of Materials in Civil Engineering 19 (2) (2007)139–148.

17] I S–2720, Methods of Test for Soils – (Part VII). Determination of Water Content-Dry Density Relation Using Light Compaction, Bureau of Indian Standards, NewDelhi, India, 1980.

18] I S–875, Code of Practice for Design Loads (Other than Earthquake) for Buildingsand Structures. Part 2. Imposed Loads, Bureau of Indian Standards, New Delhi,India, 1987.

19] K.I. Praseeda, Studies into embodied and operational energy in traditional andconventional residential buildings in India, Ph. D. Thesis. Department of Civil

20] B.V. Venkatarama Reddy, P. Prasanna Kumar, Embodied energy in cement sta-bilised rammed earth walls, Energy and Buildings 42 (3) (2010) 380–385.

21] B.V. Venkatarama Reddy, K.S. Jagadish, Embodied energy of common and alter-native building technologies, Energy and Buildings 35 (2003) 129–137.