Revealing the difference between creep behavior of hydration products of Portland cement and alkali-activated slag paste at early age

Abstract

This study investigates the early-age creep behavior of various gels in Portland cement (PC) and alkali-activated slag (AAS) pastes. The objective is to reveal the correlation between the composition and creep behavior of hydration products in these two systems. The results indicate that the creep modulus of C-A-S-H in AAS is significantly lower than that of outer products (Op) and inner products (Ip) in PC paste, even though Op exhibits higher elastic modulus than C-A-S-H. The intermixed CH has a more pronounced effect on the creep modulus of Op compared to its elastic modulus, which should be mainly attributed to the pinning effect of CH during the deformation of Op during the creep process. The lack of enhancement by high stiffness crystal phases in the matrix of AAS leads to the relatively low creep modulus of C-A-S-H.