水胶比对高强砂浆早期收缩特性的影响

Influence of Water/Binder Ratio on Initial Shrinkage of High Strength Mortar

通过设计4种不同水胶比(0.18、0.21、0.24、0.27)的高强砂浆试样,研究掺入等量硅粉和羧酸基高效减水剂时不同水胶比对高强砂浆试样的单轴抗压强度、化学收缩、自收缩和干燥收缩的影响。试验结果表明:高强砂浆的早期收缩比较明显,其化学收缩和干缩与水胶比正相关,试块抗压强度和自收缩与水胶比负相关;掺入的硅粉发生二次水化,能够提升砂浆抗压强度,增加收缩量;掺入的羧酸基高效减水剂增加了水泥的凝结时间,但一定程度减少了砂浆试样的早期收缩。

The effect of water/binder ratio on high strength mortar （ HSM） , such as the uniaxial compressive strength, chemical shrinkage, autogenous shrinkage and drying shrinkage were investigated, based on the test of samples with four different water/binder ratio （0. 18, 0.21,0.24, 0.27） mixed the same dosage of silica fume and polycarboxylate superplasticizer （ PCS）. The results show that the early shrinkage of HSM is dramatical, chemical shrinkage and drying shrinkage are positively correlated with the water/binder ratio, and the uniaxial compressive strength, autogenous shrinkage are negatively correlated with it. The compressive strength and the shrinkage of HSM samples are increased by mixing silica fume with secondary reaction of hydration ; The the cement setting time is significantly increased by mixing PCS and early shrinkage of HSM decreased with some degrees by it.