Prediction Model for Shrinkage of Lightweight Aggregate Concrete

Volumetric change due to shrinkage affects performance of structural concrete thorough itsservice life. Prediction model that could be employed to estimate shrinkage after years will be beneficial for designer in analysing such effect. Unfortunately, the existing predictinmodel for example ACI 209R-92 is developed for normal weight concrete. The validity ofthe model for estimating shrinkage of lightweight aggregate concrete (LWAC) is inquestion. This research is aimed to improve ACI 209R-92 model that will be applicable forpredicting shrinkage of LWAC. For this purpose, measurement of shrinkage of LWAC up to585 days on specimens with various curing periods were carried out. ACI 209R-92 model isutilized as starting point for the prediction of shrinkage of LWAC and then shrinkage halftime value used in the model is modified to fit with the measurements. The proposed model is confirmed by the results of other investigators. It is shown that prediction of long-term shrinkage of LWAC could be improved when shrinkage half time used in ACI 209R-92 model is 65 instead of 35.