掺粉煤灰和矿粉对混凝土开裂性能的影响

选用粉煤灰、矿粉作为掺合料以单掺和复掺的形式掺入到硅酸盐水泥混凝土中,检测其坍落度和3d、28d抗压强度以及早期抗开裂性能。研究结果表明:矿粉、粉煤灰均会降低混凝土3d强度,矿粉可以提高混凝土28d强度,粉煤灰掺量过大会降低混凝土28d强度。随着矿粉掺量的增加,混凝土坍落度随之降低,粉煤灰刚加入时会使混凝土坍落度降低,但是随着掺量的升高,坍落度会逐渐增大;开裂方面:单掺时,粉煤灰与矿粉都在掺量为37%时,抗开裂效果最佳,其中粉煤灰效果最好,复掺时,随着矿粉相对掺量的变大,裂缝的面积和数目都在增大。

The Affection to the Performance of Concrete Cracking of Fly Ash and Slag

The slump,3 days,28 days compressive strength and the early crack resistance of Portland cement concrete which paste with fly ash,slag were teated.The results showed that:slag and fly ash as the addition decreased 3d compressive strength of portland cement concrete,and slag increased the 28d compressive strength of the concrete while too high quantity of fly ash reduced it.The slag had bad impact on the reduction of slump,but the increase of fly ash made the slump of concrete large.In the aspect of cracking:when the addition of admixture is 37％,the admixture would restrain cracking effectively and fly ash worked best.When the slag mixed with ily ash,area and the number of the cracks increased with the increasing amount of the slag.