Comparative Study On The Detection And Evaluation Of Alkali Aggregate Reaction Of Concrete By Accelerated Mortar Bar Method And Concrete Prism Test

This paper uses accelerated mortar bar method and concrete prism method to test the alkali activity of tuff in the area of Urumqi and evaluates inhibition of alkali aggregate reaction of fly ash,slag powder,fly ash and slag powder composite effect,further to compare the results of experimental difference between the accelerated mortar bar method and the concrete prism test method.At the same time,the different between the stimulating effect of alkali aggregate reaction and that of fly ash on the inhibition effect by curing temperature of accelerated mortar bar method were analyzed.The main conclusions are as follows:(1)In the assessment of inhibitory effects of fly ash on alkali aggregate reaction,there have big difference between the accelerated mortar bar method and the concrete prism test method.the test results of the accelerated mortar bar method show that mixed with 20% fly ash can effectively restrain the alkali aggregate reaction,while test results of the concrete prism test results show that the effective inhibition of alkali aggregate reaction need the minimum amount of fly ash to reach 25%.When the content of fly ash is same,the rate of expansion of the accelerated mortar bar method is faster than that of concrete prism test.(2)When the accelerated mortar bar method is used to test,the curing temperature is 80?.This experiment shows that the curing temperature conditions will also stimulate effect of AAR expansion and the inhibitory effect of fly ash.,but the inhibitory effect of fly ash in this curing temperature is significantly greater than the expansion of alkali aggregate reaction.Therefore,the effect of fly ash on the inhibition of alkali aggregate reaction is exaggerated by the accelerated mortar bar method.(3)Testing accelerated mortar bar method and concrete prism test get the same results,which show that the incorporation of 45% slag powder can effectively inhibit alkali aggregate reaction,also when the same incorporation of slag powder,two methods obtain similar results in the the rate of expansion.(4)When evaluate the results of composite fly ash and slag powder for inhibiting alkali aggregate reaction,the results between the accelerated mortar bar method and the concrete prism test method have significant difference.According to the test results of composite fly ash and slag powder for inhibiting alkali aggregate reaction,the lowest dosage composite fly ash and slag powder is 30% by experimental results of the accelerated mortar bar method,while that is 40% by concrete prism test method,indicating that using the conclusion by the accelerated mortar bar test for inhibition of detection and evaluation the effect of composite fly ash and slag powder is not reliable.