石英粉、矿粉对PHC管桩混凝土力学性能的影响

Influence of Quartz Powder and Fly Ash on Mechanical Property of PHC Pipe Pile Concrete

采用石英粉（QP）和粉煤灰（FA）单、双掺制备PHC管桩混凝土,研究了石英粉、粉煤灰对压蒸工艺制备PHC管桩混凝土的立方体抗压强度（fcu）、劈裂抗拉强度（fts）和轴心抗压强度（fcp）的影响。结果表明：与纯水泥混凝土试件相比,掺量在10%30%范围内,单掺石英粉对提高fcu和fcp幅度效果最明显,在掺量不超过10%时单掺粉煤灰对fcu和fcp稍有提高,超过10%时则会降低fcu和fcp;石英粉和粉煤灰在满足fcu和fcp要求的前提下,石英粉和粉煤灰两两双掺有利于提高fts。与纯水泥混凝土试件相比,无论单掺或两两复掺石英粉、粉煤灰,均可提高PHC管桩混凝土的韧性,而掺入粉煤灰的效果最为明显;SEM分析表明,掺入粉煤灰的压蒸净浆试件中水化产物大孔少,形成了较为明显的空间网架结构,有利于提高管桩混凝土的韧性。

PHC pipe pile concrete in the autoclaved-curing was made by mixing quartz powder （QP） and fly ash （FA）. The influences of mono and dual doped QP and FA on the cube compressive strength （fcu）, tensile splitting strength （fts） and axial compressive strength （fcp） of PHC Pile cubic showed that in comparison with the non-additive mineral admixtures concrete specimens, the impact of mono doped mineral admixtures in the scope of 10%-30% for improvement of fcu and fop was QP 〉 FA. When the addition of less than 10% FA, fcu and fop were improved slightly and if the dosage extended 10%, the values offcu and fcp decreased. Under the certain condition offcu and fcp, two mixtures of QP with FA had positive influence in fts. Compared with the control specimens, mono and dual doped mineral admixtures of QP and FA could increase the toughness of PHC pipe pile concrete and the influence of FA was the most significant. SEM analysis showed that hydration products with less big holes in the autoclaved paste with the addition of FA, which formed comparatively observable spacial network and improves the toughness of concrete.