火成岩石粉对混凝土抗压强度的影响研究

Study on the influence of igneous rock powder on the compressive strength of concrete

针对机制砂生产过程中产生的石粉问题,从矿物掺合料对比、石粉掺量、石粉细度、水胶比和复合掺合料的角度,研究了火成岩石粉对混凝土抗压强度的影响。结果表明:掺加火成岩石粉混凝土与掺加粉煤灰和矿粉的混凝土相比,各龄期强度最低,3d^7d龄期强度发展和粉煤灰混凝土相当,后期强度发展较为缓慢,与粉煤灰和矿粉混凝土相差较多;火成岩石粉掺量在20%以内时,对混凝土28d前的抗压强度影响较小,建议工程中单掺火成岩石粉的掺量控制在胶凝材料的20%以内;火成岩石粉细度越细,混凝土各龄期抗压强度越高,但是抗压强度提高幅度并不明显;火成岩石粉混凝土随着水胶比的降低抗压强度增大,可以配制一般工程所需的不同强度等级混凝土;火成岩石粉与矿粉复合比和与粉煤灰复合对混凝土抗压强度贡献高,火成岩石粉与矿粉、粉煤灰6∶2∶2三元复合对混凝土抗压强度的提高效果最佳。

Aiming at the problem of stone powder obtained from the production of manufactured sand,the influence of igneous rock powder on the compressive strength of concrete is studied from the perspective of mineral admixture contrast and stone powder content, stone powder fineness and water-binder ratio and composite admixture. The results show that the concrete with igneous rock powder has the lowest strength at each age period in comparison to the concrete with fly ash and mineral powder,and the strength development is close to the fly-ash concrete in 3 ~ 7 days,and slow down in later age,so that the strength is much inferior to that of the concrete with fly ash and mineral powder. When the content of igneous rock powder is less than 20%,it has little influence on the compressive strength of concrete before 28 days. Hence,it is suggested that the content of igneous rock powder should be controlled within 20% of cementitious material in engineering. The finer the particle size of igneous rock powder is,the higher the compressive strengths of concrete at all ages is,although the enhancement of compressive strength is not prominent. The compressive strength of the concrete with igneous rock powder increases with the decrease of water-binder ratio,and the concrete with different strength grade could be allocated for general engineering. Moreover,with respect to the component of igneous rock powder and fly ash,the combination of igneous rock powder and mineral powder has a more favorable contribution to the compressive strength of concrete.Finally,whilst the igneous rock powder,mineral powder and fly ash are compounded in to a ternary composite in a ratio of 6 ∶2 ∶2,the improvement of compressive strength of concrete could be optimal.