Applied Mechanics and Materials Vols. 584-586

Abstract: Based on the fatigue test of 6 stainless steel reinforced concrete beams, number of stress cycles, dropping-coefficient of stiffness and crack width are studied. This paper mainly discussed, under different stress states and reinforcement ratio, the influence of the reinforced concrete beam with stainless steel rebar on crack development, deflection and fatigue life. It can be concluded that, the fatigue life of the stainless steel reinforced concrete beam will go up as the stress decreases. Based on the analysis of the test results, the S-N curve can be deduced.

Abstract: Precast two-way hollow slab concrete shear wall is a new structure adapted to housing industrialization. To study the effect of the vertical joint on mechanical behaviors of shear walls, one reinforced concrete shear wall and two precast concrete shear walls built with hollow slabs were quasi-statically tested under low cyclic loading. The study of failure mode and failure process of specimens shows that vertical macro-cracks occurred in precast walls under loading, which made failure behavior of walls evolve from integral wall into split wall. It also shows that relative deformation formed along the vertical joint before peak load, so the ductility of walls is increased. New type shear walls exhibit good ductility and brittle shear failure can be avoided effectively.

Abstract: The concrete composite material with basalt fiber as enhancing system in it has a lot of advantages ,including excellent mechanical properties , high temperature resistant, resistant to acid and alkali, low cost, environmental protection materials and resistance production process. It has been applied to the field of construction project. Damage of northern environment of freezing and thawing on the properties of the composite material has become a new hot issue. In order to study the characteristics of basalt fiber reinforced concrete as building composite materials in the process of freezing and thawing, this research uses the freeze-thaw cycle test to carry out the performance study on change of dynamic modulus of elasticity and quality loss of basalt fiber concrete. We use basalt fiber volume content of 0, 0.1%, 0.2% and 0.3% respectively of four groups of concrete specimens as the research object, to carry them on the freezing-thawing resisting performance test research. Research results show that the performance of dynamic modulus of elasticity and quality loss of basalt fiber concrete in freezing and thawing process is obviously better than the plain concrete. The dosage of 0.3% basalt fiber concrete freezing-thawing resisting performance is the best in the four groups of concrete samples.

Abstract: The debonding behavior at the interface between carbon fiber-reinforced plastic (CFRP) sheet and concrete is a key problem for the application of FRP plate, which has been widely applied in the civil engineering for rehabilitation and retrofitting of conventional structures. This paper presents the nonlinear finite element analysis results of the CFRP-strengthened high-strength concrete member. On the basis of the test, considering of the bond-slip relationship, explicit finite element is used for simulating the shear failure of CFRP-strengthened concrete, obtain three-dimensional deformation development diagram, describe the failure mode and the relationship between the shearing bond behavior and concrete strength. The FE results coincide with the experimental results.

Abstract: Through axial load bearing capacity test of eight steel & steel pipe reinforced concrete composite columns, the working mechanism, the ductility and the ultimate bearing capacity of the composite columns were studied, and the main factors affecting the performance of the composite columns are discussed, including concrete strength and the ferrule coefficient. The results show that the collaborative force of steel, steel pipe and concrete can effectively improve the bearing capacity of the columns, delay or inhibit the spread of oblique shear cracks in concrete and improve the ductility of the columns.

Abstract: This paper introduces the common concrete durability research background of the status quo, summarizes the corrosion resistance of concrete under the background of the main influence factors. The corrosion types and corrosion mechanism of concrete are discussed, including the corrosion mechanism of concrete base material of cement, steel corrosion mechanism and corrosion mechanism of reinforced concrete structures. From the research and the analysis of the structure formation of ordinary concrete, summarizes the common strength grade of concrete high performance-based approach.

Abstract: Statistical methods was combined with micromechanics. Based on the parallel bar system, the damage law of the concrete materials subjected to uniaxial compressive stress was simulated. Furthermore, the meso-statistical damage constitutive of concrete materials was studied base on the Weibull’s statistical theory of the strength of materials. While according to constitutive uniaxial compression test of concrete material after freezing and thawing, the parameters m and ε₀ of the model were fitted. Then the freeze-thaw damage constitutive equation of concrete was proposed base on meso-statistical damage mechanics. Finally, the experimental results was compared with theoretical models, and the rationality of the theoretical model was verified.

Abstract: CA mortar is using the domestic with river sand as aggregate currently in China, we use sand to replace river sand as fine aggregate in CA mortar. The main purpose is test the influence of dosage on aluminum in the CA mortar. Experiments show that dosage should be the best aluminum from 0.01% to 0.015 %.

Abstract: Concrete durability is closely related to the national economy and social stability, environmental protection, sustainable development is a major research topic concrete materials science, engineering and technological problems are a major concern. This paper studies resistance to chloride Ion penetration performance and anti-carbonation of low cement concrete sand hill. And combined with the test results analysis and discussion the low dosage of cement to sand concrete electric flux and the influence of carbonization resistance.

Abstract: This paper establish a whole concrete production process-based matrix with the whole concrete production process as coordinate and the three principles (maximum utilization of natural resources, minimization of pollution, optimization of plant construction) as abscissa, and put forward the key technologies and management measure to provide reference for the green production in Ready-mixed concrete industry.