低等级粉煤灰对混凝土流动性和强度的影响

摘要

To study the influence of low-grade fly ash on the concrete strength and liquidity,three grades concrete of C20,C30 and C40 were prepared by using equal amount of fly ash to replace ce-ment content of 0, 10%,20% and 30% (mass fraction,the same below).The fluidity and strength of each number of concrete were tested.The results show that low-grade coal ash is advanta-geous to the liquidity of concrete.With the increase of the dosage of fly ash,7d,28d compressive and splitting tensile strength decreases gradually,56d compressive and splitting tensile strength of C30 and C40 is closed to the reference concrete,but the 56d compressive strength of C20 concrete is different from that of reference concrete.%为研究低等级粉煤灰对混凝土流动性和强度的影响，以粉煤灰等量取代水泥量（质量分数，下同）为0、10％、20％和30％，制备 C20、C30、C403个等级的混凝土，检测各个编号混凝土的流动性和强度。试验结果表明：低等级粉煤灰掺入对混凝土的流动性是有利的，随着粉煤灰掺量增加，混凝土的7 d、28 d 抗压和劈裂抗拉强度逐渐降低，C30、C40混凝土的56 d 抗压和劈裂抗拉强度逐步接近基准混凝土，但 C20混凝土的56d 抗压强度与基准混凝土相差较大。