Title: High Performance Concrete Containing SCMs and LWA for Internal Curing

Author(s): Yuguo Zhong

Publication: Web Session

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Date: 10/25/2020

Abstract:
Joint spalling deterioration in jointed plain concrete pavement, JPCP, is a major durability problem associated with deicer salt application in an area with wet-freeze climate such as Michigan. Once the cementitious concrete binder reaches a fully saturated pore condition, the problem of ice formation is exacerbated in the joint area as deicer salt ions create a partial water-slush in the surface contact area, which accelerates frost erosion of the cementitious binder for certain material conditions. Erosion of the cementitious binder combined with truck loading exacerbates joint deterioration. In this study, a number of enhancements to frost resistance are explored, including permeability reduction (pozzolans), shrinkage reduction (internal curing) and these factors are evaluated from a laboratory testing program sponsored by the Michigan Department of Transportation (MDOT) with the major aim to improve the durability of the cementitious binder to moisture-related damage from frost and shrinkage. A mathematical model was given to characterize different stages of the shrinkage process. The thermal strain was measured by using the maturity concept and coefficient of thermal deformation so that autogenous shrinkage can be separated from the total strain. The major findings are: autogenous shrinkage can be mitigated by using pre-wetted fine LWA at a 25% to 40% volume content of total fine aggregate. The shrinkage rate decreased nonlinearly as the LWA content increased. Based on this rule, a function was given to predict the shrinkage rate. Excellent F-T resistance with respect to internal cracking and surface salt scaling was found for LWA contents of 25% or 40%.