BUILDING MATERIALS III

BUILDING MATERIALS IIICONCRETEBUILDING MATERIALS Building materialis any material which is used forconstructionpurposes. Many naturally occurring substances, such asclay, rocks,sand, and wood, even twigs and leaves, have been used to construct buildings. Apart from naturally occurring materials, many man-made products are in use, some more and some less synthetic. The manufacture of building materials is an established industry in many countries and the use of these materials is typically segmented into specific specialty trades, such ascarpentry,insulation,plumbing, androofingwork. They provide the make-up ofhabitats andstructuresincludinghomes.Naturally occurring substancesBrushIce and snowMud and clayMonolithic clay structureStructural clay blocksSandStone or rockThatchWood and timber

Man-made substancesCement compositesConcreteFabricFoamGlassGypcreteMetalPlastics

Importance of Building MaterialsCertain facts which affects the choice of materials for a particular project.Climatic background.Availability of materialPositioning of the projectEconomic aspectAesthetics

Physical propertiesDensity Porosity Hygroscopicity Water absorptionWeathering resistanceWater permeabilityFrost resistanceHeat conductivityThermal capacityFire resistance RefractorinessChemical resistancedurabilityConcrete as a structural materialThese days there are two commonly used structural materials : concrete and steelThey sometime complement one another, and sometimes complete with each other.The man on the job needs to know more about concrete than about steel.Quality of concrete depends on the preparations and processes on site.CONCRETEConcrete in the broadest sense, is any product or mass made by the use of cementing medium.Generally, this medium is the product of reaction between hydraulic cement and water.Concrete is made with several types of cements and also containing pozzolan, flyash, blast-furnace slag, aregulated set additive, sulphur, admixtures, polymers, fibres and so on.Concrete can be heated, steam-cured, autoclaved, vacuum-treated, hydraulically pressured, shock vibrated, extruded and sprayed.Good concreteThe ingredients of good concrete is exactly same as any other concrete and the difference is due entirely to know-how.There are two stages: fresh state and hardened state.For fresh state consistence of the mix is such that the concrete can be compacted.At hardened state requirement is a satisfactory compressive strength.