Effect of Dune Sand on Drying Shrinkage Cracking of Fly Ash Concrete

In this study, the drying shrinkage cracking characteristics of concrete containing 30% fly ash were investigated for various dune sand (DS) replacements and unit water contents. In the results of compressive strength, the mixture with a DS-to-fine aggregate (DS/FA) ratio of 10% showed the highest value, which was 17.6% higher than the lowest value. However, in the results of restrained drying shrinkage cracking, the mixtures with a DS/FA ratio of 20% showed the highest crack resistance, which was 24% higher than the lowest crack resistance. Therefore, it is necessary to consider DS replacement according to the required performance of concrete. The restraint effect factors of the aggregates were analyzed based on the relationship between the volume change of each aggregate and the change in the net time to cracking. The restraint effect factor of crushed sand was 0.71-0.98 and that of DS was 0.56-0.90 when that of the coarse aggregate (CA) was 1.

Automated summary

This study investigated the drying shrinkage cracking characteristics of concrete containing 30% fly ash for different dune sand replacements and unit water contents. The results showed that considering DS replacement is necessary to achieve the required performance of concrete.