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针对目前路面水泥混凝土易于出现塑性开裂的情况,为更合理优化路面混凝土原材料与配合比设计参数,采用笠井芳夫教授提出的大板法,对比研究了水泥细度、矿物掺和料种类及掺量、混凝土配合比设计参数对路面混凝土早期塑性开裂性能的影响。试验结果表明,水泥的比表面积越大,矿物掺和料掺量越高,水灰比越小,混凝土浆集比越大时,越不利于路面水泥混凝土的塑性开裂控制。且相对于粉煤灰与矿粉,硅灰作为矿物掺和料时,硅灰将更显著降低混凝土抗塑性开裂等级。为提高路面水泥混凝土的抗裂性,宜选择比表面积小于360 kg/m3的水泥,水灰比大于0.4、浆集比小于275∶725的配合比设计参数。当混凝土中掺加活性矿物掺和料时,应加强混凝土的早期养护,以抑制塑性裂缝的出现。
In view of the fact that the plasticity of pavement cement concrete is prone to plastic cracking, in order to optimize the design parameters of pavement concrete raw material and mix proportion rationally, the method of large-panel method proposed by Professor Fukui Fukui was used to compare the fineness of cement, the type and content of mineral admixture Effect of Concrete Mix Design Parameters on Early Plastic Cracking of Pavement Concrete. The results show that the greater the specific surface area of cement, the higher the content of mineral admixture, the smaller the ratio of water to cement and the greater the ratio of concrete to aggregate, the less conducive to the plastic cracking control of pavement concrete. And compared to fly ash and slag, silica fume as a mineral admixture, the silica fume will significantly reduce the concrete resistance to plastic cracking. In order to improve the crack resistance of pavement cement, cement with specific surface area of less than 360 kg / m3 should be selected, and the design parameters of mix ratio with water-cement ratio greater than 0.4 and slurry-collection ratio less than 275: 725 should be selected. When mixed with active mineral admixtures in concrete, concrete should be strengthened early conservation to suppress the emergence of plastic cracks.