Modification of ACI209R-92 Concrete Shrinkage Model for Partial Replacement of Cement with Fly Ash and Sand with Pond Ash

A lot of researchers have been committed to studying various mathematical models for forecasting shrinkage strain developed in concrete and have found many computational models. Those models only predict the linear shrinkage of concrete. But volumetric shrinkage gives clear ideas about shrinkage strain produced inside the structure. However, the previous investigation usually focused on the shrinkage of control cement concrete or cement was replaced with one kind of supplementary cementitious material. The influence of multiple supplementary materials as both cement and sand replacement on shrinkage has not been studied, and this is very important in practice for saving cement and sand. In this research, cement has been replaced with fly ash up to 40 % and sand has been replaced with pond ash up to 20 % individually as well as simultaneously. A total of 27 mixes has been prepared by using three water–cement ratios, and the influence of fly ash and pond ash on volumetric shrinkage has been studied. It is found that when cement is replaced with fly ash up to 40 %, the shrinkage of concrete shows 47 % less than the shrinkage result of control concrete. Similarly, the replacement of sand with pond ash up to 20 % results in the reduction of shrinkage of concrete up to 22 %, and the results for the simultaneous replacement of cement with fly ash and sand with pond ash show a reduction of shrinkage of concrete up to 62 % as compared with the shrinkage of control concrete. Shrinkage strains for all 27 mixes have been determined by using different shrinkage models as well as a laboratory test. It is found that the shrinkage strain found from the ACI model matches with shrinkage strain determined from laboratory tests in a better way as compared with other models. Further, the ACI model has been modified to determine the shrinkage strain of concrete, prepared from supplementary cementitious materials.