纳米材料调控水泥基材料自收缩性能研究

Study on Self-shrinkage of Cement-based Materials Controlled by Nanomaterials

研究了纳米黏土、碳纳米管和纳米碳酸钙调控水泥基材料早期自收缩性能,并结合抗压强度和X射线衍射探讨了不同纳米材料对水泥基材料自收缩影响机理。结果表明:随着纳米黏土掺量的增加,水泥基材料各龄期抗压强度呈现减少趋势,碳纳米管和纳米碳酸钙对水泥基材料的影响表现为增强作用。纳米材料在各个龄期均能降低水泥浆体自收缩。纳米材料的掺入密实了水泥基体结构,丰富了水化产物。纳米黏土具有吸水膨胀性,能在水化过程中释放水分,降低自干燥效应;碳纳米管不仅具备纳米填充效应,其搭接形成的骨架网络结构可抑制水泥基体自收缩;纳米碳酸钙一方面降低水泥基材料孔隙率,另一方面可与水泥中的C3A反应生成膨胀性产物碳铝酸钙,补偿浆体自收缩。

The early self-shrinkage properties of cement-based materials controlled by nano-clay,carbon nanotubes and nano calcium carbonate are studied.Combined with compressive strength and X-ray diffraction,the influence mechanism of different nanomaterials on the self-shrinkage of cement-based materials is discussed.The results show that the compressive strength of cement-based materials decreases with the increase of nano-clay content,and the effects of carbon nanotubes and nano calcium carbonate on cement-based materials are enhanced.Nanomaterials can reduce the self-shrinkage of cement paste at all ages.The addition of nano materials compacts the cement matrix structure and enriches the hydration products.Nano-clay has water absorption and expansion,which can release water in the hydration process and reduce the self-drying effect;Carbon nanotubes not only have nano filling effect,but also the skeleton network structure formed by their overlapping can inhibit the self-shrinkage of cement matrix;on the one hand,nano calcium carbonate can reduce the porosity of cement-based materials,on the other hand,it can react with C3A in cement to produce expansive product calcium carboaluminate to compensate the self-shrinkage of slurry.