This document provides information on structural light weight concrete. It defines light weight concrete as a special concrete that weighs less than conventional concrete due to using light weight coarse aggregates. These aggregates can be natural materials like pumice or artificial materials like clay that have been fired to develop a porous structure. Light weight concrete has densities between 1440-1840 kg/m3 compared to 2240-2400 kg/m3 for normal concrete. It is used to reduce the dead load of structures, allowing smaller structural elements like columns and footings. Light weight concrete also provides better strength-to-weight and fire resistance properties than normal concrete.

1. MODULE-01
ADVANCE STRUCTURAL
CONCRETES

3. LIGHT WEIGHT
CONCRETE

4. WHAT IS STRUCTURAL LIGHT WEIGHT CONCRETE?
• LIGHT WEIGHT CONCRETE IS A SPECIAL CONCRETE WHICH WEIGHS LIGHTER THAN
CONVENTIONAL CONCRETE.
• THE CONCRETE MIXTURE IS MADE WITH A LIGHTWEIGHT COARSE AGGREGATE.
• LIGHT WEIGHT AGGREGATES SUCH AS NATURAL AGGREGATES LIKE PUMICE AND
ARTIFICIAL AGGREGATES LIKE CLAY, SLATE OR SHALE THAT HAVE BEEN FIRED IN A
ROTARY KILN TO DEVELOP A POROUS STRUCTURE.
• IT IS A VERSATILE MATERIAL WHICH CONSISTS OF A CEMENT (PORTLAND CEMENT
AND FLY ASH MIXTURE) BASED MORTAR MIXED WITH AT LEAST 20% OF VOLUME
AIR.
• HAS IN PLACE DENSITY(UNIT WEIGHT) OF (1440 TO 1840 KG/CUM) COMPARED TO
NORMAL WEIGHT CONCRETE (2240 TO 2400 KG/CUM).

5. WHY IS STRUCTURAL LIGHT WEIGHT CONCRETE?
• TO REDUCE THE DEAD LOAD OF A CONCRETE STRUCTURE, WHICH THEN ALLOWS THE
STRUCTURAL DESIGNER TO REDUCE THE SIZE OF COLUMNS, FOOTING AND OTHER
LOAD BEARING ELEMENTS.
• STRUCTURAL LIGHTWEIGHT CONCRETE MIXTURES CAN BE DESIGNED TO ACHIEVE
SIMILAR STRENGTHS AS NORMAL WEIGHT CONCRETE.
• STRUCTURAL LIGHTWEIGHT CONCRETE PROVIDES A MORE EFFICIENT STRENGTH-TO-
WEIGHT RATIO IN STRUCTURAL ELEMENTS.
• IN BUILDINGS, STRUCTURAL LIGHTWEIGHT CONCRETE PROVIDES A HIGHER FIRE-RATED
CONCRETE STRUCTURE.

6. Principle behind LWC:
The basic principle behind the making of light weight concrete is by inducing
the air in concrete.
To achieve the above principle practically, there are 3 different ways.
• By replacing the conventional mineral aggregates by cellular porous aggregates (Light
weight agg. Concrete).
• By incorporating the air or gas bubbles in concrete (Aerated concrete).
• By omitting the sand from the concrete (No- fines concrete).
 Three types of LWC :
Light weight aggregate concrete
Aerated concrete
No – fines concrete

7. Light weight aggregate concrete:
 Basically two types of light weight aggregates
Natural aggregates
Artificial aggregates
 Natural light weight aggregates are less preferred over artificial aggregates.
 Important natural aggregates – Pumice & Scoria
 Artificial aggregates are usually produced by expanding the rocks such as Shale,
Slate, Perlite, Vermiculite, etc.,
 Type of aggregates decides the density of concrete.
 Density of concrete as low as 300 kg/m3 can be achieved.
 Compressive strength varies from 0.3Mpa to 40Mpa.

9. Expanded Perlite
Exfoliated Vermiculite

10. CELLULAR LIGHTWEIGHT CONCRETE
SINTERED FLY ASH LIGHTWEIGHT AGGREGATES
Foamed slag

11. Pumice Porespumice aggregate
clinkers
Bloated clay

12. Aerated concrete:
 Produced by introducing air into the concrete.
 It is also called cellular concrete having voids between 0.1mm to 1mm size.
 Two ways are there to induce the air in concrete.
 Gas concrete
 Foamed concrete
 Gas concrete is produced by chemical reaction in which gas is produced in the
concrete.
 Finely divided aluminum powder is generally used as gas producing agent.
 Its quantity is about 0.2% of weight of cement.
 Aluminum powder reacts with Ca(OH)2 to liberate hydrogen bubbles.

13. Aerated concrete (contd.)
 Powdered zinc, aluminum alloy or hydrogen peroxide can also be used as gas
producing agents.
 Foamed concrete is produced by adding foaming agent, usually hydrolyzed
protein or resin soaps, during mixing
 In some cases, stable preformed foam is also added during mixing.
 Concrete of densities 300kg/m3 to 1100kg/m3 can be obtained.
 Compressive strength varies from 12Mpa to 14Mpa for a concrete of density
500kg/m3.
 Generally autoclaved aerated concrete is used.
 Aerated concrete has higher thermal movement, higher shrinkage and higher
moisture movement compared to light weight aggregate concrete of same
strength.

14. Autoclaved Aerated
concrete blocks
Surface texture of AAC

15. No – fines concrete:
 It is a type of light weight concrete produced by omitting the fine aggregates
from conventional concrete.
 This concrete has only cement, coarse aggregate and water.
 Due to absence of fine aggregates, concrete will have large voids, resulting in
light weight.
 Even though there is reduction in strength, there is no capillary movement of
water, resulting in low permeability and consequently more durable.
 Density of concrete will be less if coarse aggregates are of single size ranging
from 10mm to 20mm rather than well graded aggregates.
 No – fines concrete with lighter coarse aggregates, we can get density as low
as 640 kg/m3.

16. No – fines concrete (contd.)
 In this concrete, strength criteria depends on cement content in the
concrete than water – cement ratio.
 Drying shrinkage is comparatively less. But shrinkage takes place rapidly
than conventional concrete.
 Thermal conductivity is also comparatively less.
 No – fines concrete has better architectural appearance.

17. USES OF LIGHT WEIGHT CONCRETE?
• HEAT INSULATION ON ROOFS.
• CONSTRUCTION OF PARTITION WALLS AND PANEL WALLS IN FRAME STRUCTURES.
• SURFACE RENDERED FOR EXTERNAL WALLS OF SMALL HOUSES.
• CASTING STRUCTURAL STEEL TO PROTECT IT AGAINST FIRE AND CORROSION OR AS A
COVERING FOR ARCHITECTURAL PURPOSES.
• SCREEDS AND WALLS WHERE TIMBER HAS TO BE ATTACHED BY NAILING.
• IT IS WIDELY USED AS LOOSE-FILL INSULATION IN MASONRY CONSTRUCTION WHERE IT
ENHANCES FIRE RATINGS, REDUCES NOISE TRANSMISSION, DOES NOT ROT AND TERMITE
RESISTANT

18. CHARACTERISTICS OF LIGHT WEIGHT CONCRETE

19. ADVANTAGES OF LIGHT WEIGHT CONCRETE?
• ECONOMICAL AS SAVINGS IN TRANSPORTING AND HANDLING PRECAST UNITS ON SITE.
• BETTER NAILING
• EASY TO HANDLE
• REDUCED DEAD LAOD OF BUILDING.
DISADVANTAGES OF LIGHT WEIGHT CONCRETE?
• MIXING TIME IS LONGER
• DOES NOT BEAR ANY EXTERNAL LOAD.
• DIFFICULT TO PLACE BECAUSE OF POROSITY OF THE AGGREGATE,THE CEMENT MORTAR MAY
SEPARATE THE AGGREGATE AND FLOAT TOWARDS THE SURFACE.

20. EXAMPLE
 THE LIGHTWEIGHT CONCRETE HAS BEEN USED SINCE THE 18TH CENTURY BY THE
ROMANS.
 IT WAS ALSO USED IN CONSTRUCTION DURING THE FIRST WORLD WAR . THE
UNITED STATES USED MAINLY FOR SHIPBUILDING.
PANTHEON, ROME

21. HIGH STRENGTH
CONCRETE

22. WHAT IS HIGH STRENGTH CONCRETE?
• HIGH-STRENGTH CONCRETE HAS A COMPRESSIVE STRENGTH GREATER THAN 40 MPA.
• HIGH STRENGTH CONCRETE IS MADE BY LOWERING THE WATER CEMENT (W/C) RATIO TO 0.35
OR LOWER.
WHYIS HIGH STRENGTH CONCRETE?
• TO BUILD HIGH-RISE BUILDINGS BY REDUCING COLUMN SIZES AND INCREASING AVAILABLE
SPACE.
• TO BUILD THE SUPERSTRUCTURES OF LONG-SPAN BRIDGES AND TO ENHANCE THE DURABILITY
OF BRIDGE DECKS.

23. HOW TO DESIGN HIGH STRENGTH CONCRETE
• HIGH STRENGTH CONCRETE MIXTURES WILL HAVE A HIGH CEMENTITIOUS
MATERIAL CONCTENT THAT INCREASES THE HEAT OF HYDRATION AND POSSIBLY
HIGHER SHRINKAGE LEADING TO THE POTENTIAL OF CRACKING.
• HIGH STRENGTH CONCRETE MIXTURES GENERALLY NEED TO HAVE A LOW WATER-
CEMENTITIOUS MATERIALS RATIO (W/CM).
• W/CM RATIOS CAN BE IN THE RANGE OF 0.23 TO 0.35. THESE LOW W/CM RATIO
ARE ONLY ATTAINABLE WITH QUITE LARGE DOSES OF HIGH RANGE WATER
REDUCING ADMIXTURES.
CLASSIFICAION OF HIGH STRENGTH CONCRETE
o NORMAL STRENGTH CONCRETE 20-50 MPa
o HIGH STRENGTH CONCRETE 50-100 MPa
o ULTRA STRENGTH CONCRETE 100-150 MPa

24. MATERIALS FOR HIGH STERNGTH CONCRETE?
 CEMENT
• ALMOST ANY ASTM PORTLAND CEMENT TYPE CAN BE USED TO OBTAIN CONCRETE WITH
COMPRESIVE STRENGTH UP TO 60 MPA.
• IN ORDER TO OBTAIN HIGHER STRENGTH MIXTURES WHILE MAINTAINING GOOD
WORKABILITY, IT IS NECESSARY TO STUDY CAREFULLY THE CEMENT COMPOSITION AND
FINENESS.
• IT IS ALSO REQUIRED THAT THE CEMENT IS COMPATIBLE WITH CHEMICAL ADMIXTURES
TO OBTAIN THE HIGH-STRENGTH.
 AGGREGATE
• SELECTION OF RIGHT AGGREGATES PLAYS AN IMPORTANT ROLE FOR THE DESIGN OF HIGH
STRENGTH CONCRETE MIX.
• THE LOW-WATER TO CEMENT RATIO USED IN HIGH-STRENGTH CONCRETE MAKES THE
CONCRETE DENSER AND THE AGGREGATE MAY BECOME THE WEAK LINK IN THE
DEVELOPMENT OF THE MECHANICAL STRENGTH.
• EXTREME CARE IS NECESSARY, THEREFORE, IN THE SELECTION OF AGGREGATE TO BE
USED IN VERY HIGH-STRENGTH CONCRETE.

25. GUIDELINES FOR THE SELECTION OF MATERIALS
 THE HIGHER THE TARGETED COMPRESSIVE STRENGTH, THE SMALLER THE MAXIMUM SIZE
OF COARSE AGGREGATE.
 UP TO 70 MPACOMPRESSIVE STRENGTH CAN BE PRODUCED WITH A GOOD COARSE
AGGREGATE OF A MAXIMUM SIZE RANGING FROM 20 TO 28 MM.
 TO PRODUCE 100 MPACOMPRESSIVE STRENGTH AGGREGATE WITH A MAXIMUM SIZE OF
10 TO 20 MM SHOULD BE USED.
DIFFERENCE BETWEEN NSC AND HSC
• NORMAL STRENGTH CONCRETE, THE MICROCRACKS FORM WHEN THE COMPRESSIVE STRESS
REACHES ~ 40% OF THE STRENGTH.
• THE CRACKS INTERCONNECT WHEN THE STRESS REACHES 80-90% OF THE STRENGTH
• THE FRACTURE SURFACE IN NSC IS ROUGH.THE FRACTURE DEVELOPS ALONG THE TRANSITION
ZONE BETWEEN THE MATRIX AND AGGREGATES.
• THE FRACTURE SURFACE IN HSC IS SMOOTH.

26. ADVANTAGES OF HIGH STRENGTH CONCRETE?
• REDUCES AMOUNT OF STEEL
• REDUCED CONSTRUCTION COST
• REDUCED MEMBER SIZES
• INCREASES RENTAL SPACE.
• HIGH COMPRESSIVE STRENGTH
• IMPROVED CONSTRUCTABILITY
LIMITATIONS OF HIGH STRENGTH CONCRETE?
• DAMAGED AT HIGH TEMPERATURE I.E LESS RESISTANCE TO FIRE.
• MUST BE EXPERTISE IN SELECTION OF INGREDIENTS.

27. CHARACTERISTICS OF HSC?
• HIGH EARLY STRENGTH
• HIGH MODULUS OF ELASTICITY
• HIGH ABRASION RESISTANCE
• HIGH DURABILITY AND LONG LIFE IN SEVERE ENVIRONMENTS
• LOW PERMEABILITY AND DIFFUSION
• RESISTANCE TO CHEMICAL ATTACK
• HIGH RESISTANCE TO ADVERSE CLIMATIC CONDITIONS
• TOUGHNESS AND IMPACT RESISTANCE
• VOLUME STABILITY
• EASE OF PLACEMENT
• COMPACTION WITHOUT SEGREGATION
• INHIBITION OF BACTERIAL AND MOLD GROWTH

28. USES OF HIGH STRENGTH CONCRETE?
• USE OF HSC IN COLUMN SECTION DECREASES THE COLUMN SIZE.
• USE OF HSC IN COLUMN DECREASES AMOUNT OF STEEL REQUIRED FOR SAME COLUMN.
• IN HIGH RISE BUILDING, USE OF HSC INCREASES THE FLOOR AREA FOR RENTAL PURPOSE.
• IN BRIDGES,USE OF HSC REDUCES THE NUMBER OF BEAMS SUPPORTING THE SLAB.
VIDYA SAGAR SETU BRIDGE,
(KOLKATTA,INDIA)
Use of HSC instead of NSC increases the span
between two column and strength.
JOINGY BRIDGE , PARIS
NSC is replaced by HSC because of which volume of
concrete decreases by 30%.

29. EXAMPLES
PATRONAS TOWER,
MALAYSIA
TIMES SQUARE,
HONG KONG
UNION SQUARE BUILDING,
USA

30. SUBMITTED BY:
•SACHIN SAGAR
•SHEHZAD KHAN
•SIMRAN BHUGRA
•TAMANNA BANSAL
•VISHAKHA GOEL