Influence of lightweight aggregate and calcium sulfoaluminate cement on deformation of ordinary Portland cement mortar and concrete

Shrinkage mitigation;Lightweight aggregate;Calcium sulfoaluminate cement

Wu, Di ; Mondal ; Paramita

关键词: Shrinkage mitigation;    Lightweight aggregate;    Calcium sulfoaluminate cement;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/87979/WU-THESIS-2015.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Cracking due to shrinkage is a predominant cause of concrete constructions degradation. Several strategies were developed to mitigate shrinkage in concrete. The addition of pre-soaked lightweight aggregate (LWA) and usage of calcium sulfoaluminate (CSA) cement are two common methods applied in shrinkage mitigation. Pre-soaked LWA supplies additional moisture to cement paste during hydration, thereby compensating for the water consumption that occurs during hydration and drying. CSA cement induces expansion of the matrix, which counteracts shrinkage.This thesis presents the results from a wide range of tests that examined the effectiveness of LWA and CSA cement on shrinkage mitigation of mortar and concrete. The results indicate that the addition of pre-soaked LWA could reduce the shrinkage under sealed conditions, and the effectiveness is influenced by the dosage of pre-soaked LWA, w/c ratio and soaking time of LWA. Under unsealed conditions, the addition of pre-soaked LWA is not an effective way on shrinkage mitigation. However, LWA does affect the shrinkage of the matrix by influencing the stiffness of the entire matrix. The combined use of pre-soaked LWA and CSA cement could more effectively mitigate shrinkage, and the effect was more significant with increasing dosage of LWA.