煤矸石对水泥性能的影响及机理分析

Influence of Coal Gangue on Cement Properties and Its Mechanism Analysis

煤矸石作为掺合料广泛应用于水泥生产中,其选料、配料存在原料有害杂质含量把关不严,大量超掺煤矸石,生产的水泥使用中会出现浮黑浆、需水量比过大、坍落度损失快、与减水剂适应性能差等问题,、使用生、熟煤吁石等量替代水泥,并掺入酯类、醚类两种聚羧酸减水剂,分别测试水泥净浆流动度、减水率、水泥胶砂强度,结合扫描电镜及XRD测试结果分析机理。研究表明:随着煤矸石取代水泥掺量的增加,水泥净浆初始流动度明显降低,且损失严重;煤矸石中含有的伊利石和蒙脱石结构及组分类似,影响聚羧酸减水剂使用效果,生煤砰石比熟煤矸石对减水剂性能影响更大;随着煤矸石掺量增加,在水泥净浆流动度变化率上,酯类较醚类聚羧酸减水剂变化平稳,水泥胶砂试件抗压、抗折强度都在不断下降,而且掺量越大,强度降低愈加明显,其中生煤矸石又相较熟煤矸石更加敏感。

As a blending material, coal gangue is widely used in cement production. The selection of materials and ingredients in the presence of hannful impurities in raw materials is not strict. A large amount of super-added coal gangue will produce floating black pulp in the production of cement, and the water demand ratio is too large. The slump loss is fast, and the adaptability of the plasticizer agent is poor. The cement paste fluidity, water reduction rate and cement mortar strength were respectively tested with ester and ether polycarboxylic acid water reducing agents by mixing raw and calcined coal gangue into cement. The mechanism was discussed combined with scanning electron microscopy and XRD test results. The analysis showed that the initial fluidity of cement paste was significantly reduced and the loss was serious with the increase of cement content replaced by coal gangue. The structure and composition of illite and montmorillonite contained in coal gangue were similar, which affected the reduction of polycarboxylate. The use effect of the coal gangue had a greater influence on the performance of the plasticizer than the calcined coal gangue. With the increase of the coal gangue content, the fluidity of cement paste changed more smoothly with esters than ether polycarboxylic acid water reducer. The compressive strength and flexural strength of cement mortar samples were decreasing continuously, and the larger the amount, the more obvious the strength reduction is. The raw coal gangue was more sensitive than the calcined coal gangue.