Research On Properties Of Foamed Concrete With Fine Sand And Fly Ash

Foamed concrete, classified as lightweight concrete, is produced by introducing foam into cement paste or mortar. Foamed concrete with density of200-1600kg/m3is produce by introducing different volume of foam and could be applied as structural, nonstructural, thermal insulating or backfilling material.In this paper, a series of experiments was undertaken and the effect to mechanical and sorption properties of different grades of cement, different sand/cement ratios, different fly ash/cement ratios, replacing cement with both fine sand and fly ash and density was investigated; The relationship of compressive and tensile splitting strength of mixes with fine sand and fly ash was regressed.It is found that with same sand/cement ratio, the higher cement grade, the bigger compressive and tensile splitting strength. Softening coefficient of mixes with52.5R and42.5R cement are very close but bigger than mixes with32.5R cement.With same cement, as the sand/cement ratio grows, the28-day compressive and tensile splitting strength reduces and the tensile/compressive strength ratio grows. As sand/cement ratio grows,72-hour water absorption and softening coefficient grow firstly, then reduce and get to max when the sand/cement ratio is1.0. Besides, softening coefficient reduces with increase of72-hour water absorption.Mixes with higher fly ash content have lower early age strength, but the strength grows more as the age increases. Replacing at most67%cement with fly ash, the28-day strength don’t reduce apparently or increase. When sand/cement equals fly ash/cement, mixes with fly ash show higher compressive and tensile splitting strength but lower tensile/compressive strength ratio. Adding fine sand or fly ash could enhance softening coefficient of foamed concrete. Mixes with fine sand show lower water absorption than mixes with fly ash.As the density reduces, compressive and tensile splitting strength of foamed concrete get much smaller, the softening coefficient and static modulus of elasticity in compression also get smaller, but the tensile compressive strength ratio gets bigger. Adding fine sand and fly ash together can improve the softening coefficient, and with the same density softening coefficient of foamed concrete reduces with increase of water absorption.