Shrinkage model for concrete incorporating coal gangue coarse and fine aggregates

Our study aims to formulate a model for predicting the shrinkage behaviour of concrete incorporating coal gangue coarse and fine aggregates (CGCA and CGFA). In order to achieve this, the study conducted an experiment measuring the shrinkage of coal gangue aggregate concrete (CGAC) over a period of 126 days. The experiment involved varying replacement ratios of CGCA and CGFA, including 0%, 50%, and 100% of both types. Test results show that: (1) both CGCA and CGFA significantly increased concrete shrinkage strain, and the shrinkage strain increased by 145% when both CGCA and CGFA were 100% used, (2) the CGCA has a more pronounced influence on the shrinkage compared to CGFA, and (3) the incorporation of CGCA leads to a faster development of shrinkage in the concrete, whereas CGFA has no significant effect on the shrinkage development over time. A novel theoretical model was developed that can accommodates the coal gangue aggregate's effect on the development and ultimate value of shrinkage strain in CGAC. Benchmarking analysis was carried out using the study's test data and data from literature, which showed that the proposed model can well predict the CGAC shrinkage.