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- PH: +91 95431 00500
- Email: info@shreeshabuildingsolution.org
Contact Info
- Old no 47, dhanalakshmipuram south, Central Studio Rd, Singanallur, Tamil Nadu 641005
- +91 95431 00500
- info@shreeshabuildingsolution.org
Shreesha Building Solution
FOAM CONCRETE & NAAC
Concrete is a manmade material used in building construction consists of aggregates which is bonded together by cement and water. The other major part of concrete besides the cement is the aggregate. Aggregate includes sand, crushed stone, gravel, slag, burnt shale and burnt clay. Fine aggregate refers smaller size of aggregates which behaves like structural filler material in concrete. Coarse aggregate is crushed stones or gravels, which tends to improve quality and bond characteristics and it also gives high flexural strength to concrete.
Concrete can be categorized into two which are conventional concrete and lightweight concrete. Foam Concrete is not the same as conventional concrete and does not have the same characteristics. Foam concrete is one type of lightweight concrete having a minimum of 20% (by volume) of mechanically entrained foam in the plastic mortar. It contains no large aggregates; it is composed of binder, filler material, water and foam. It possesses high flow ability, low self weight, and minimum consumption of aggregate, control strength and excellent thermal insulation properties
PROPERTIES OF FOAM CONCRETE
Foam concrete is not as same as conventional concrete and does not have the same characteristics. The properties of lightweight foam concrete can be classified into fresh state properties and hardened state properties. The fresh state property is stability. The hardened properties are classified into physical, mechanical, durability and functional characteristics
- Stability
- Drying Shrinkage
- Air-Voids
- Density
- Compressive Strength
- Flexural & Tensile Strengths
- Durability of Foam Concrete
- Water Absorption
- Fire Resistance
Stability
Foam Concrete Properties
As foam concrete cannot be subjected to compaction or vibration, it should have flow ability and self-compact ability. These two properties are evaluated in terms of stability of foam concrete, which is affected by the water content in the base mix, amount of foam added along with the other solid ingredients in the mix.
Foam Concrete Properties
Drying Shrinkage
Foam concrete possesses high drying shrinkage due to the absence of coarse aggregate, i.e., up to 10 times greater than those observed on normal weight concrete. The shrinkage of foam concrete reduces with density, which is attributed to the lower paste content affecting the shrinkage in low-density mixes. In a comparative study on the shrinkage behaviour with sand and quarry dust as filler, foam concrete with quarry dust exhibited smaller drying shrinkage which is attributed to the higher shrinkage restraining capacity of quarry dust as compared to sand.
Foam Concrete Properties
Air-Voids
The pore structure of cementation material, predetermined by its porosity, permeability and pore size distribution, is a very important characteristic as it influences the properties such as strength and durability.
Foam Concrete Properties
Density
Density can be either in a fresh or hardened state. Fresh density is required for mix design and casting control purposes. While specifying the density, the moisture condition needs to be indicated as the comparison of properties of foam concrete from different sources can have little meaning without a close definition of the degree of dryness.
Foam Concrete Properties
Compressive Strength
The compressive strength decreases exponentially with a reduction in density of foam concrete. The specimen size and shape, the method of pore formation, direction of loading, age, water content, characteristics of ingredients used and the method of curing are reported to influence the strength of cellular concrete in total. Other parameters affecting the strength of foam concrete are cement–sand and water–cement ratios, curing regime, type and particle size distribution of sand and type of foaming agent used.
Foam Concrete Properties
Flexural and Tensile Strengths
The ratio of flexural strength to compressive strength of cellular concrete is in the range of 0.25–0.35. Splitting tensile strengths of foam concrete are lower than those of equivalent normal weight and lightweight aggregate concrete with higher values observed for mixes with sand than those with quarry dust. This increase is attributed to the improved shear capacity between sand particles and the paste phase.
Low density foam concrete has a tensile strength of about 0.2 N/mm2; but higher densities approximately 1500 kg/m3, its tensile strength range is from 2-3 N/mm2. ASTM C869-91 recommends that foamed concrete should have a minimum tensile strength of 0.17 N/mm2.
Foam Concrete Properties
Durability of Foam Concrete
Foam concrete is a highly porous material which is often assumed to be prone to rapid fluid ingress; however the interconnectivity of pores has not been established. Water is not easily absorbed into foam concrete if it is formed with hydrophobic surfactants.
Foam Concrete Properties
Water Absorption
The water absorption of foam concrete is mainly influenced by the paste phase and not all artificial pores are taking part in water absorption, as they are not interconnected. Expressing water absorption as percentage by mass can lead to misleading results when foam concrete is concerned because of larger differences in density. The oxygen and water vapour permeability of foam concrete have been observed to increase with increasing porosity and quarry dust content. Permeability coefficient of lightweight foamed concrete is proportional to unit weight and inversely proportional to pore ratio.
Foam Concrete Properties
Fire Resistance
At high temperature the heat transfer through porous materials is influenced by radiation, which is an inverse function of the number of air–solid interfaces traversed. Hence along with its lower thermal conductivity and diffusivity, the foam concrete may result in better fire resistance properties.
Applications of Foam Concrete with different densities
| Density (kg/m3) | Applications |
|---|---|
| 300 – 600 | Used for roof and floor insulation against heat, Sound and also for interspaces filling between brickwork leaves in underground walls, insulation in hollow blocks and any other filling situation where high insulating properties are required. |
| 600 – 900 | Used for the production of precast blocks and panels for curtain and partition walls, slabs for false ceilings, Thermal insulation and soundproofing screeds in multi-level residential buildings. |
| 900 – 1200 | Used in concrete blocks and panels for outer leaves of buildings, architectural ornamentation as well as partition walls and floor screeds. |
| 1200 – 1800 | Used in precast panels of any dimension for commercial and industrial use, garden ornaments and other uses where structural concrete of light Weight is an advantage. |
ADVANTAGES OF FOAM CONCRETE
Does not settle, hence requires no compaction.
Lightweight - does not impose large loadings.
Free flowing - spreads to fill all voids.
Excellent load spreading characteristics.
Once placed requires no maintenance.
Reliable quality control - batches are easy to reproduce.
Foam Concrete was low water absorption over time.
Excellent fire resistant properties.
Highly cost effective compared with other methods.
Enables fast work & Easy to re-excavate.
Sufficiently strong and durable for most applications.
Excellent sound and thermal insulation.
BENEFITS OF FOAM CONCRETE
The foam concrete blocks brings so many advantages. Some of them are Tremendous weight reduction, high thermal insulation, optimum fire rating, substantial material savings, no gravel used, little cement, less steel in structure and foundation, easy and fast production, no primary energy and reduced transportation costs, boon for remote areas with only sand available.
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FOAM CONCRETE APPLICATION AREAS
- Sunken filling areas
- Inverted beams filling areas
- Portico slabs filling
- Loose fill insulation, loft, cavity, acoustic filling
- trench backfill
- precast blocks
- precast wall elements / panels
- prefabricated insulation boards
- Raise roof levels
- bridge approaches / embankments
- insulating compensation laying
- insulation floor screeds
- Light weight concrete for weathering course areas
- insulation roof screeds
- trench reinstatement
- sub-base in highways
- filling of hollow blocks
- pipeline abandonment / annular fill
