THE PRACTICALITIES AND THEORY OF USING CRACK WIDTH SUMMATION TO ESTIMATE ASR EXPANSION

It has been shown that for structures affected by alkali-silica reacti on (ASR), the deterioration of concrete properties can be related to t he amount of expansion that has occurred. If the amount of expansion i s known, it is also possible to calculate the prestress in the reinfor cement and concrete resulting from the restraint to expansion. This ma y be beneficial when appraising such a structure. The present method o f evaluating expansion from the sum of crack widths is crude, and vary ing results have been obtained by different researchers. Results from a series of tests in which crack width and angle were examined and rel ated to expansion are presented here. A method for predicting expansio n, which improves reliability, is proposed, and reasons for variations in results are discussed.