养护龄期对水泥混凝土性能和微观结构的影响

研究养护龄期对磷铝酸盐水泥混凝土抗压强度、表面透气和吸水性能影响,利用多种测定仪对混凝土水化产物物相组成、微观结构形貌、电性能和孔结构特性等进行了分析.此外,还分析了不同种类水泥早期水化特性,并解析了磷酸盐水泥具有早强和高强特性的缘由.结果表明:养护龄期对混凝土表观性能和微观结构影响较大,混凝土表观性能与微观结构之间存在密切联系;随着养护龄期延长,混凝土抗压强度不断增加,表面透气和吸水系数不断降低,其微观结构更加致密,孔的分形维数降低,这是由于生成的水化产物不断增多,减少了混凝土总孔隙含量造成的.磷铝酸盐水泥混凝土性能优于相同龄期的硅酸盐水泥混凝土,这是由于2种水泥属于不同体系,其水化生成物和反应机理不同.

Influence of Curing Age on Properties and Micro Structure of Concrete

Influence of curing age on compressive strength, air permeability and water absorptivity of phosphoaluminate cement concrete(PALC) was investigated. The phase composition and morphology of hydration products, electrical properties, pore structure and distribution of concrete were analyzed by various instruments. In addition, the hydration heat test and the cause for early high strength of PAC were investigated as well introduced to test the hydration heat and explain the cause for early high strength of PAC. The results show that the effect of curing age on the apparent performance and micro structure of the concrete is great, and they are related closely. With age, the compressive strength becomes higher, air permeability and absorptivity of concrete decrease. The corresponding fractal dimension of the pore and the micro structure are changed as well. The reason for that is that the more hydration products are generated and the porosity of the concrete is reduced. Furthermore, the properties of phosphoaluminate cement concrete are better than that of Portland cement because of different hydration products and mechanism.