Study On The Mechanism Of Concrete Alkali Silica Reaction Under Multiple Factors

Alkal-silica reaction(ASR) is the most important content in concrete durability, and durability of concrete is usually determined by its interaction with environment. So study on the effect of this interaction between ASR and environmental factors such as load can help us understand the mechanism of concrete ASR.Based on the inflation rate、relative dynamic elastic modulus、AC impedance spectroscopy、MIP and SEM as the research method, the study on the mechanism of concrete alkali silica reaction under different dosage aggregate、continuous bending load and sulphate attack is carried out in this article.The study shows that AC impedance spectroscopy is a new detection method of non damage. It can be a measure to evaluate concrete ASR. The parameter of AC impedance spectroscopy is connected with pore microstructure in concrete. Resistance of pore solution and phase angle can be used to estimate the alkali aggregate reactivity as a measure. For early age concrete specimen, continuous bending load plays a significant role in concrete ASR in this article. And continuous bending load worsens the influence on concrete ASR with the increase of load. When the continuous bending load reaches25%ultimate load, concrete ASR accelerates significantly. With the continuous bending load increases further, concrete ASR accelerates much slowly. Sulfate attack accelerates concrete ASR. It worsens the damage effect on concrete ASR with the increase of sulfate concentration. As time goes to60weeks, the higher the sulfate concentration is, the more obvious the accelerating effect is. When the active SiO2content is higher in concrete, SiO2adsorbs OH-ions in the pore solution plentifully. It leads to that OH-ions is not enough and the number of alkaline silicic acid gel decreases. For early age concrete, the ratio between the active alkali aggregate and inactive aggregate haves an impact on concrete ASR. There is the worst point between the active alkali aggregate and inactive aggregate in the concrete ASR. Relative dynamic elasticity modulus reduce quickly and is a good means to measure ASR in the early stage of concrete. But in the later stage, relative dynamic elasticity modulus reduce much slowly as time goes to60weeks. It can not be used to estimate concrete ASR at this moment.