稻壳灰对水泥基及混凝土性能影响的试验研究

Experimental Research on the Influence of Rice Husk Ash on the Property of Cement-based Materials and Concrete

通过对不同粉磨时间、不同掺量稻壳灰(RHA)水泥基试样需水量、凝结时间和水泥胶砂强度的测试,讨论了RHA掺量及粉磨时间对水泥需水量、凝结时间的影响。结果表明,掺加RHA会增大水泥需水量,延长水泥初凝、终凝时间,当稻壳灰粉磨时间为45 min,掺量为10%时,对水泥浆的需水量和凝结时间影响不大。通过研究稻壳灰活性确定了稻壳灰粉最佳磨时间为45 min,RHA、RHA/粉煤灰(FA)部分取代水泥后,混凝土7和28 d抗压强度与基准组相比均有所下降,56 d抗压强度得到提高,其中复掺10%RHA/5%FA效果最优,较基准混凝土抗压强度提高19%。采用RCM法和电通量法研究了RHA对混凝土抗氯离子渗透性能的影响,结果表明,掺10%RHA/15%FA后混凝土抗氯离子渗透性能得到改善,抗氯离子渗透性能排列顺序为:R10F15>F25>JZ。

According to the test on water demands, setting time and compressive strength of RHA cement based on different grinding time and amounts of RHA, the effects of the grinding time and the volume on water demand, setting time have been discussed. Results show that the water demand of cement increases and setting time extends when a large amount of cement is replaced by RHA. Little effects of water de- mand and setting time occur when the grinding time of RHA is 45 min and 10% of RHA is added.h is determined that the grinding time is 45 minutes by testing the activity of rice husk ash. Compared with the basic concrete, 7d and 28d of concrete compressive strength decreases, 56d of concrete compressive strength is improved when cement is replaced by RHA and RHA/FA. Mixed powder of RHA（10%） /FA is the best and can make the compressive strength increases by 19% compared with basic concrete. The chloride ion penetration of concrete is stud- ied by using RCM and the electric flux method. The results show that the chloride ion penetration of concrete is improved when 10% of the rice husk ash and 15% of the fly ash is added to concrete. The order of chloride ion penetration resistance is R10F15〉F25〉JZ.