A Study On Mechanical And Deformation Properties Of Hydraulic Concret Contating Different Cementitious Materials

In the practical project application of concrete, the ultimate tensile stress of concrete is not able to resist the temperature stress and restrained stress in terms of heat of hydration and volumetric changes. This behavior will result in the crack formation and cause destructive damage to hydraulic structures. The cracking of hydraulic and mass concrete has attracted much attention. In order to solve the cracking of mass concrete, a further study on mechanical properties, hydration characteristics and shrinkage properties of concrete is strongly needed, and cementitious materials are regarded as a base in the study for they are the most important material of concrete. This thesis sets the type of cement, fly ash, water-binder ratio and so on as the experimental variables, and studies on compressive and flexural strength of hydraulic mortar, compressive strength and tensile strength of hydraulic concrete, and semi-adiabatic temperature evolutions, autogenous deformation and drying shrinkage of both of them.The following conclusions can be drawn from the study:1、Low heat cement and fly ash reduce the early-age strength of mortar and concrete, but the later-age strength grows rapider; in the same curing temperature, the strength of concrete has a greater value because of the lower w/b ratio.2、There is a good relationship between the compressive strength and tensile strength, tensile Young’s modulus or ultimate tensile strain of hydraulic concrete. The relationship is regardless of composition of cementitious materials and w/b.3、Semi-adiabatic temperature evolution of mortar and concrete is the same with each other in the influence rule of test variables. The values and rates of temperature rise of mortars or concrete with moderate heat cement were higher than those with low heat cement; The values and rates of temperature rise of mortars or concrete which contain fly ash or with higher w/b were lower.4、The autogenous deformation of mortars with moderate heat cement is much more than those with low heat cement, while there is just a little difference when it comes to concrete. The influence of w/b ratio and fly ash addition on the autogenous deformation of mortar is the same with that of concrete. The autogenous deformation of concrete increases because of the lower w/b ratio. Fly ash reduces the autogenous deformation of concrete, but also the dilatability of magnesium oxide.5、There was a strong relativity of drying shrinkage between cement mortar and concrete, and it can be described by polynomial.