Effect of SBR and limestone powder on properties of concrete

الملخص EN

This 1nvestigation is conducted to study the effect of adding (SBR + limestone powder) to concrete mix (1 : 1.5 : 3) (cement : Sand : gravel) with w / c = 0.5, and (SBR + Limestone powder) with concentration of (10 % + 2 % ), (15 % + 2 % ) and (20 % + 2 % ) by volume of water and by weight of cement consequently .

compressive strength at ages (7, 28, 60) days was tested, also absorption and splitting tensile strength were also measured.

Also (SBR + limestone powder) was added to cement mortar (1 : 2) (cement : sand) with w / c = 0.42, and (SBR + limestone powder) with concentration of (10 % + 2 % ), (15 % + 2 % ) and (20 % + 2 % ) by volume of water and by weight of cement consequently.

Drying shrinkage cracking of this mortar was tested.

As well as SBR was used as bonding mortar layer between old and new concrete layers, the compressive strength of bonded samples was tested.

The results indicate that the use of (SBR + limestone powder) in a concentration of ( 10 % + 2 % ) and ( 15 % + 2 % ) by volume of water and by weight of cement consequently cause slight increase in compressive strength by about [3 %, 1.9 % and 2 %] for ages ( 7, 28 and 60) days respectively , and by about [ 6.3 % , 5.2 % and 4 %] for ages (7, 28 and 60) days respectively , but the addition of (SBR + limestone powder) in concentration of ( 20 % + 2 %) cause reduction in compressive strength by about [ 10.6 %, 8.6 % and 9.5 % ) for ages (7, 28 and 60 ) days respectively , while the use of ( SBR + limestone powder ) in all concentration cause slight increase in splitting tensile strength , also it reduces the absorption of concrete Also, it was found that the addition of (SBR + limestone powder) to cement mortar retards the occurrence of shrinkage cracks.

The use of SBR as bonding layer showed increasing in compressive strength of the bonded samples compared with samples having old and new concrete without bond layer.