复掺纤维和粉煤灰的面板混凝土性能研究

摘要

为了考察纤维和粉煤灰对面板混凝土力学性能和体积稳定性的影响,试验研究了复掺粉煤灰和纤维的面板混凝土力学性能、干缩性能以及早期抗裂性能,并与基准混凝土进行了对比.结果表明:复掺粉煤灰和纤维,可以同时发挥粉煤灰混凝土后期强度增长快的特点以及纤维抗裂增韧的效果,复掺粉煤灰和纤维的混凝土90 d龄期抗压强度接近基准混凝土,28 d和90 d劈拉强度和极限拉伸值超过基准混凝土.纤维和粉煤灰可以约束混凝土的干缩,复掺粉煤灰和纤维的混凝土干缩率明显低于基准混凝土干缩率.复掺纤维和粉煤灰减少了水泥浆体和混凝土早期的收缩,并抑制了裂纹的产生和发展,从而提高了硬化水泥浆体和混凝土的抗裂能力.%To study the effects of fly ash and PVA fiber on the mechanical properties and the volume stability,the mechanical properties,drying shrinkage performance and early crack resistance of concrete slab under compound addition of fly ash and PVA fiber are tested,and the results are compared with UPTC. The results show that owing to the rapid strength growing of fly ash in later age and the good crack resistance effect of PVA,the compressive strength of concrete mixed with fly ash and PVA fiber is close to that of UPTC on 90thday,and the splitting tensile strengths and ultimate tensile values exceed those of the reference con-crete on 28thday and 90thday. Fibers and fly ash can work together to constrain the shrinkage of concrete,so the drying shrink-age of concrete mixed with fly ash and PVA fiber is significantly lower than that of UTPC. The addition of PVA fiber and fly ash can reduce the early shrinkage of cement paste and concrete and inhibit the development of cracks to improve the cracking resist-ance of cement paste and concrete.