Influences of mineral admixtures and aggregates on concrete shrinkage and creep

Objective This study investigated the shrinkage cracking caused by concrete shrinkage and creep, as well as explored the influences of different mineral admixtures and aggregates on shrinkage and creep properties of concrete. Method The concrete specimens, containing silicate cement with different non-clinker compositions and different aggregates, were made. The compressive strength, tensile strength, shrinkage and creep of different types of concrete specimens at different ages were investigated. Based on this, a thermo-mechanical model of concrete was established. Subsequently, the influence of internal material structure on these phenomena was analyzed to investigate the influence of aggregate type on hardening temperature, shrinkage strain, and creep development. Result The concrete with granite aggregate has the highest compressive strength and tensile strength among the concretes with the same cement and at the same age. The concrete with basalt aggregate has the minimum shrinkage strain. The concrete with gravel aggregate has the largest creep strain. The concrete with fly ash cement has the minimum shrinkage strain, the largest creep strain, the highest compressive strength and tensile strength among the concretes at the same age and with the same aggregate. The calculation results of concrete hardening temperature, shrinkage strain, and creep strain are consistent with the measured results, indicating the model 's validity. The concrete hardening temperature, shrinkage strain, and creep strain with different aggregates have the same variation pattern. Conclusion Considering compressive strength, tensile strength, hardening temperature, shrinkage strain, and creep strain comprehensively, the basalt can be regarded as the optimal aggregate, while fly ash cement serves as the best non-clinker component for concrete. The findings provide a reference for effectively controlling cracks caused by concrete shrinkage and creep.