沸石粉取代部分硅灰的超高性能混凝土力学性能研究

相比于硅灰,沸石粉是一种可就地取材、价格低廉的矿物掺合料。采用沸石粉取代硅灰制备超高性能混凝土(UHPC),研究了沸石粉掺量、水胶比和钢纤维体积掺量对沸石粉UHPC力学性能的影响。结果表明:沸石粉取代部分硅灰降低了UHPC的3 d强度,而随着龄期的增加,15%(质量分数)取代率的沸石粉增加了其强度,30%(质量分数)沸石粉取代率影响不大;沸石粉有助于改善UHPC后期韧性;水胶比的增加降低了沸石粉UHPC强度,但水胶比为0.16和0.14的试件强度相差不大;适量钢纤维有助于提高沸石粉UHPC强度,其最佳体积掺量范围为2.5%~3.0%。

Mechanical Properties of UHPC with Zeolite Powder Replacing Part Silica Fume

Compared with silica fume, zeolite powder is a local mineral admixture with the low price. Zeolite powder was used to replace silica fume to prepare ultra-high performance concrete (UHPC). The effects of zeolite powder content, water to binder ratio and volume content of steel fiber on the mechanical properties of UHPC were studied. The results show that when part silica fume is replaced by zeolite powder, the 3 d strength are reduced. And with the increase of ages, zeolite powder with the replacement rate of 15% (mass fraction) increases the strength of UHPC, while zeolite powder with the replacement rate of 30% (mass fraction) has little effect on the strength. Zeolite powder improves the toughness of UHPC at the later ages. Although the increased water to binder ratio decreases the strength, there is no the significant increase of strength between UHPC with water to binder ratio of 0.16 and 0.14. The utilization of steel fiber with appropriate amount is helpful to improve the strength of UHPC with zeolite powder, and the optimal percentage range of volume content of steel fiber is 2.5%~3.0%.