fero-cement as bldg. mat

8/18/2019 Fero-cement as Bldg. Mat.

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FERRO-CEMENT ASBUILDING MATERIAL


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GENERAL

FERROCEMENT IS PRINCIPALLY THE SAME AS REINFORCED

CONCRETE (RCC), BUT HAS THE FOLLOWING DIFFERENCES:

• ITS THICKNESS RARELY EXCEEDS 25 MM, (WHILE RCC COMPONENTS

ARE SELDOM LESS THAN 1 MM)!

• A RICH PORTLAND CEMENT MORTAR IS USED, WITHOUT ANY

COARSE AGGREGATE AS IN RCC!

• COMPARED WITH RCC, FERROCEMENT HAS A GREATER

PERCENTAGE OF REINFORCEMENT, COMPRISING CLOSELY

SPACED SMALL DIAMETER WIRES AND WIRE MESH, DISTRIBUTED

UNIFORMLY THROUGHOUT THE CROSS"SECTION!

FERRO-CEMENT AS BUILDING MATERIAL


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• ITS TENSILE"STRENGTH"TO"WEIGHT RATIO IS HIGHER THAN RCC,

AND ITS CRACKING BEHA#IOUR SUPERIOR !

• FERROCEMENT CAN BE CONSTRUCTED WITHOUT FORMWORK

FOR ALMOST ANY SHAPE!


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•FERROCEMENT IS A RELATI#ELY NEW MATERIAL,

•WHICH WAS FIRST USED IN FRANCE, IN THE MIDDLE OF THE 1$TH

CENTURY, FOR THE CONSTRUCTION OF A ROWING BOAT!

• ITS USE IN BUILDING CONSTRUCTION BEGAN IN THE MIDDLE OF

THE 2TH CENTURY IN ITALY!

•ALTHOUGH ITS APPLICATION IN A LARGE NUMBER OF FIELDS HAS

RAPIDLY INCREASED ALL O#ER THE WORLD,

•THE STATE"OF"THE"ART OF FERROCEMENT IS STILL IN ITS

INFANCY, AS ITS LONG"TERM PERFORMANCE IS STILL NOT

KNOWN!


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MORTAR COMPOSITION

• THE ESSENTIAL INGREDIENTS OF THE MORTAR WHICH

REPRESENTS ABOUT $5 % OF FERROCEMENT ARE PORTLAND

CEMENT, SAND, WATER, AND IN SOME CASES AN ADMIXTURE!

• MOST LOCALLY A#AILABLE, STANDARD CEMENT TYPES ARE

SUITABLE, BUT SHOULD BE FRESH, OF UNIFORM CONSISTENCY

AND WITHOUT LUMPS OR FOREIGN MATTER !

• SPECIAL CEMENT TYPES ARE NEEDED FOR SPECIAL USES,

• &!'! SULPHATE"RESISTANT CEMENT IN STRUCTURES EXPOSED TO

SULPHATES (AS IN SEAWATER)!


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FERROCEMENT BOAT CONSTRUCTION IN THE 1$S


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• ONLY CLEAN, INERT SAND SHOULD BE USED,

(FREE FROM ORGANIC MATTER AND DELETERIOUS SUBSTANCES, AND RELATI#ELY

FREE FROM SILT AND CLAY!)

• PARTICLE SIES SHOULD NOT EXCEED 2 MM AND UNIFORM

GRADING IS DESIRABLE TO OBTAIN A HIGH"DENSITY WORKABLE

MIX! LIGHTWEIGHT SANDS (&!'! *+-./0- ., 340-&, 0/&67 .8.0"6&07./7

3.70-) CAN ALSO BE USED, IF HIGH STRENGTHS ARE NOT

RE9UIRED!

• FRESH DRINKING WATER IS THE MOST SUITABLE!• IT SHOULD BE FREE FROM ORGANIC MATTER, OIL, CHLORIDES,

ACIDS AND OTHER IMPURITIES! SEAWATER SHOULD NOT BE USED!


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• ADMIXTURES CAN BE USED FOR WATER REDUCTION,

• THUS INCREASING STRENGTH AND REDUCING PERMEABILITY (BY ADDING

SO"CALLED SUPERPLASTICIERS); FOR WATERPROOFING;

• FOR INCREASED DURABILITY (&!'! BY ADDING UP TO


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• THE RECOMMENDED MIX PROPORTIONS ARE: SAND=CEMENT

RATIO OF 1!5 TO 2!5, AND WATER=CEMENT RATIO OF !!

• GREAT CARE SHOULD BE EXERCISED IN CHOOSING AND

PROPORTIONING THE CONSTITUENT MATERIALS,

• ESPECIALLY WITH A #IEW TO REDUCING THE WATER

RE9UIREMENT,

• AS EXCESSI#E WATER WEAKENS THE FERROCEMENT!


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REINFORCEMENT

• THE REINFORCING MESH (WITH MESH OPENINGS OF ? TO 25 MM)

MAY BE OF DIFFERENT KINDS, THE MAIN RE9UIREMENT BEING

FLEXIBILITY!

• IT SHOULD BE CLEAN AND FREE FROM DUST, GREASE, PAINT,

LOOSE RUST AND OTHER SUBSTANCES!

• GAL#ANIING, LIKE WELDING, REDUCES THE TENSILE

STRENGTH, AND THE INC COATING MAY REACT WITH THE

ALKALINE EN#IRONMENT TO PRODUCE HYDROGEN BUBBLES ON

THE MESH! THIS CAN BE PRE#ENTED BY ADDING CHROMIUM

TRIOXIDE TO THE MORTAR!


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• THE #OLUME OF REINFORCEMENT IS BETWEEN > AND @ % IN BOTH

DIRECTIONS, IE BETWEEN


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• S9UARE WELDED WIRE MESH IS MUCH STIFFER THAN

CHICKEN WIRE MESH AND PRO#IDES INCREASED RESISTANCE

TO CRACKING! HOWE#ER, INADE9UATE WELDING PRODUCES

WEAK SPOTS!

• S9UARE WO#EN WIRE MESH HAS SIMILAR CHARACTERISTICS

AS WELDED MESH, BUT IS A LITTLE MORE FLEXIBLE AND EASY

TO WORK WITH THAN WELDED MESH! MOST DESIGNERS

RECOMMEND S9UARE WO#EN MESH OF 1 MM (1$ GAUGE) OR

1!? MM (1? GAUGE) DIAMETER WIRES SPACED 1< MM (!5 IN)

APART!


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• EXPANDED METAL LATH, WHICH IS FORMED BY SLITTING

THIN GAUGE SHEETS AND EXPANDING THEM IN THE

DIRECTION PERPENDICULAR TO THE SLITS, HAS ABOUT THE

SAME STRENGTH AS WELDED MESH, BUT IS STIFFER AND

HENCE PRO#IDES BETTER IMPACT RESISTANCE AND BETTER

CRACK CONTROL! IT CANNOT BE USED TO MAKE

COMPONENTS WITH SHARP CUR#ES!


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• SKELETAL STEEL, WHICH GENERALLY SUPPORTS THE WIRE

MESH AND DETERMINES THE SHAPE OF THE FERROCEMENT

STRUCTURE, CAN BE SMOOTH OR DEFORMED WIRES OF

DIAMETERS AS SMALL AS POSSIBLE (GENERALLY NOT MORE

THAN 5 MM) IN ORDER TO MAINTAIN A HOMOGENOUS

REINFORCEMENT STRUCTURE (WITHOUT DIFFERENTIAL

STRESSES)! ALTERNATI#ELY, SKELETAL FRAMEWORKS WITH

TIMBER OR BAMBOO HA#E BEEN USED, BUT WITH LIMITED

SUCCESS!

• FIBRES, IN THE FORM OF SHORT STEEL WIRES OR OTHER

FIBROUS MATERIALS, CAN BE ADDED TO THE MORTAR MIX TO

CONTROL CRACKING AND INCREASE THE IMPACT RESISTANCE!


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• THE FIRST STEP IS TO PREPARE THE SKELETAL FRAMEWORK

ONTO WHICH THE WIRE MESH IS FIXED WITH A THIN TIE WIRE (OR

IN SOME CASES, BY WELDING)! A MINIMUM OF TWO LAYERS OF

WIRE MESH IS RE9UIRED, AND DEPENDING ON THE DESIGN, UP TO

12 LAYERS HA#E BEEN USED (WITH A MAXIMUM OF 5 LAYERS PER

CM OF THICKNESS)!

• THE SAND, CEMENT AND ADDITI#ES ARE CAREFULLY

PROPORTIONED BY WEIGHING, MIXED DRY AND THEN WITH

WATER! HAND MIXING IS USUALLY SATISFACTORY, BUT

MECHANICAL MIXING PRODUCES MORE UNIFORM MIXES,

REDUCES MANUAL EFFORT AND SA#ES TIME! THE MIX MUST BE

WORKABLE, BUT AS DRY AS POSSIBLE, FOR GREATER FINAL

STRENGTH AND TO ENSURE THAT IT RETAINS ITS FORM AND

POSITION BETWEEN APPLICATION AND HARDENING!


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• AFTER CHECKING THE STABILITY OF THE FRAMEWORK AND

WIRE MESH REINFORCEMENT, THE MORTAR IS APPLIED EITHER

BY HAND OR WITH A TROWEL, AND THOROUGHLY WORKED

INTO THE MESH TO CLOSE ALL #OIDS! THIS CAN BE DONE IN A

SINGLE APPLICATION, THAT IS, FINISHING BOTH SIDES BEFORE

INITIAL SET TAKES PLACE! FOR THIS TWO PEOPLE ARE NEEDED

TO WORK SIMULTANEOUSLY ON BOTH SIDES!


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• THICKER STRUCTURES CAN BE DONE IN TWO STAGES,

THAT IS, PLASTERING TO HALF THICKNESS FROM ONE SIDE,ALLOWING IT TO CURE FOR TWO WEEKS, AFTER WHICH THE

OTHER SURFACE IS COMPLETED!

COMPACTION IS ACHIE#ED BY BEATING THE MORTAR WITH

A TROWEL OR FLAT PIECE OF WOOD!

• CARE MUST BE TAKEN NOT TO LEA#E ANYREINFORCEMENT EXPOSED ON THE SURFACE, THE MINIMUM

MORTAR CO#ER IS 1!5 MM!

• EACH STAGE OF PLASTERING SHOULD BE DONE WITHOUT

INTERRUPTION, PREFERABLY IN DRY WEATHER OR UNDER

CO#ER, AND PROTECTED FROM THE SUN AND WIND! AS INCONCRETE CONSTRUCTION, FERROCEMENT SHOULD BE

MOIST CURED FOR AT LEAST 1> DAYS!


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APPLICATIONS

• BOAT CONSTRUCTION (ONE OF THE MOST SUCCESSFUL USES!

ESPECIALLY IN CHINA)!

• EMBANKMENT PROTECTION, IRRIGATION CANALS, DRAINAGE

SYSTEMS!

• SILOS (ABO#E GROUND OR UNDERGROUND) FOR STORAGE OF

GRAIN AND OTHER FOODSTUFFS!

• WATER STORAGE TANKS, WITH CAPACITIES UP TO 15 M

• SEPTIC TANKS AND A9UA PRI#IES, AND E#EN COMPLETE

SER#ICE MODULES WITH WASHING AND TOILET FACILITIES!

• PIPES, GUTTERS, TOILET BOWLS, WASHBASINS, AND THE LIKE!

• WALLS, ROOFS AND OTHER BUILDING COMPONENTS, OR

COMPLETE BUILDING, EITHER IN SITU OR IN THE FORM OF


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• FURNITURE, SUCH AS CUPBOARDS, TABLES AND BEDS, ETC! AND

#ARIOUS ITEMS FOR CHILDRENS PLAYGROUNDS!

SOME APPLICATIONS OF FERROCEMENT

FURNITURE, SANITARY UNITS, ROOFING ELEMENTS AT THE

STRUCTURAL ENGINEERING RESEARCH CENTRE, MADRAS, INDIA!

LATRINE S9UATTING SLAB, WASHING BASIN, TOILET FLUSH

CISTERN AND WATER TANK (MADE OF 5 S9UARE ELEMENTS,

ASSEMBLED ON SITE) AT THE HOUSING BUILDING RESEARCH

INSTITUTE, DHAKA, BANGLADESH!


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ADANTAGES

• THE MATERIALS RE9UIRED TO PRODUCE FERROCEMENT AREREADILY A#AILABLE IN MOST COUNTRIES!

• IT CAN TAKE ALMOST ANY SHAPE AND IS ADAPTABLE TO

ALMOST ANY TRADITIONAL DESIGN!

• WHERE TIMBER IS SCARCE AND EXPENSI#E, FERROCEMENT IS A

USEFUL SUBSTITUTE!• AS A ROOFING MATERIAL, FERROCEMENT IS A CLIMATICALLY

AND EN#IRONMENTALLY MORE APPROPRIATE AND CHEAPER

ALTERNATI#E, TO GAL#ANIED IRON AND ASBESTOS CEMENT

SHEETING!

• THE MANUFACTURE OF FERROCEMENT COMPONENTS RE9UIRES

NO SPECIAL E9UIPMENT, IS LABOUR INTENSI#E AND EASILY

LEARNT BY UNSKILLED WORKERS!


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• COMPARED WITH REINFORCED CONCRETE, FERROCEMENT IS

CHEAPER, RE9UIRES NO FORMWORK, IS LIGHTER, AND HAS A

TEN TIMES GREATER SPECIFIC SURFACE OF REINFORCEMENT,

ACHIE#ING MUCH HIGHER CRACK RESISTANCE!

• FERROCEMENT IS NOT ATTACKED BY BIOLOGICAL AGENTS,

SUCH AS INSECTS, #ERMIN AND FUNGUS!


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PROBLEMS

• FERROCEMENT IS STILL A RELATI#ELY NEW MATERIAL,

THEREFORE ITS LONG"TERM PERFORMANCE IS NOT

SUFFICIENTLY KNOWN!

• ALTHOUGH THE MANUAL WORK IN PRODUCING FERROCEMENT

COMPONENTS RE9UIRES NO SPECIAL SKILLS, THE STRUCTURAL

DESIGN, CALCULATION OF RE9UIRED REINFORCEMENTS AND

DETERMINATION OF THE TYPE AND CORRECT PROPORTIONS OF

CONSTITUENT MATERIALS RE9UIRES CONSIDERABLE KNOW"

HOW AND EXPERIENCE!

• GAL#ANIED MESHES CAN CAUSE GAS FORMATION ON THE

WIRES AND THUS REDUCE BOND STRENGTH!

• THE EXCESSI#E USE OF FERROCEMENT FOR BUILDINGS CAN


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REMEDIES !

• RESEARCH ON THE CONDITION OF OLDER FERROCEMENT

STRUCTURES!

• DE#ELOPMENT OF SIMPLE CONSTRUCTION GUIDELINES

AND RULES OF THUMB WHICH CAN BE APPLIED WITHOUTSPECIAL TECHNICAL KNOWLEDGE!

• GAL#ANIED MESH CAN BE IMMERSED IN WATER FOR 2>

HOURS AND THEN DRIED FOR 12 HOURS, IN ORDER TO

ALLOW THE SALTS USED DURING GAL#ANIING TO COME TO

THE SURFACE! THE RESIDUE CAN THEN BE BRUSHED OFF!


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• PROBLEMS WITH GAL#ANIED MESH CAN BE REDUCED BY

ADDING CHROMIUM TRIOXIDE TO THE MIXING WATER!

• COMPLETE ENCLOSURE OF DWELLING UNITS WITH

FERROCEMENT COMPONENTS (IE FOR FLOOR, WALLS AND

ROOF) SHOULD BE A#OIDED!


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fero-cement as bldg. mat

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