油页岩半焦作为水泥混合材的可行性研究

Feasibility Study of Oil Shale Semi-Coke as Cement Admixture

选取4种热解温度(300℃、400℃、500℃、600℃)半焦,通过扫描电镜(SEM)对油页岩半焦的微观结构进行分析,然后采用油页岩半焦等质量(0%、5%、10%、15%、20%、25%)替代水泥,测试标准稠度需水量、胶砂流动度和不同龄期的水泥胶砂的抗折、抗压强度。结果表明:油页岩半焦呈层片状、且表面多孔,随着热解温度的升高,微孔和小孔数量逐渐减少,中、大孔数量增加;掺入油页岩半焦会增加水泥标准稠度需水量,降低胶砂流动度,半焦替换量和水泥标准稠度需水量之间存在较强的线性关系;随着油页岩半焦热解温度的升高,水泥胶砂抗折和抗压强度先增大后减小,在500℃时力学性能达到最佳;随着油页岩半焦替换量的增加,水泥胶砂抗折和抗压强度都逐渐降低,当油页岩半焦替换量为15%时,500℃热解半焦水泥胶砂56 d力学性能与P·Ⅰ42.5基准水泥胶砂接近。

Four pyrolysis temperatures(300℃,400℃,500℃,600℃)semi-coke were selected,and the microstructure of oil shale semi-coke was analyzed by scanning electron microscopy(SEM),and then equal masses of oil shale semi-coke(0%,5%,10%,15%,20%,25%)were used to replace cement.The standard consistency water requirement,the fluidity of mortar and the flexural and compressive strength of cement sand at different ages were tested.The results show that the semi-coke of oil shale is lamellar and porous.With the increase of pyrolysis temperature,the number of micropores and small pores gradually decreases,and the number of medium and large pores increases.Adding oil shale semi-coke increases the water requirement of standard consistency and reduces the fluidity of mortar.There is a strong linear relationship between the content of oil shale semi-coke and the water requirement of standard consistency.With the increase of the pyrolysis temperature of oil shale semi-coke,the flexural and compressive strength of cement sand increases first and then decreases,and the mechanical properties reach the best at 500℃.With the increase of the amount of oil shale semi-coke,the flexural and compressive strength of cement sand gradually decrease.When the oil shale semi-coke content is 15%,the mechanical properties of the 56 d pyrolysis semi-coke cement sand at 500℃are close to that of the P·Ⅰ42.5 benchmark cement sand.