Coefficients of Thermal Expansion of Concrete with Different Coarse Aggregates–Texas Data

Abstract

The first section of this paper summarizes the efforts of Texas Department of Transportation (TxDOT) to evaluate the coefficients of thermal expansion (COTEs) of a total of 93 concrete mixtures, of which the only difference is the coarse aggregate incorporated. The mean COTE value of siliceous gravel concrete is about 30 % higher than that of limestone concrete. The data in Texas shows that the upper 50 % COTE values of limestone concrete overlaps the lower 20 % COTE values of siliceous gravel concrete. The results strongly suggest that pre-qualification of coarse aggregate for typical paving concrete in aspect to COTE should be considered. A model by Emanuel and Hulsey is used to back calculate COTE of coarse aggregate. The second section of this article compares the COTE data set on existing pavement measured by Federal Highway Administration with those obtained at TxDOT concrete laboratory.

Thermal Expansion of Cement Paste at Various Relative Humidities after Long-term Drying: Experiments and Modeling

“…Hygrothermal properties of C-S-H have been studied at the atomistic scale by molecular dynamics (Qomi et al 2015) and Monte Carlo simulations (Honorio 2019) of tobermorite, one of the crystalline forms of C-S-H. Experimental measurement of the CTE at various relative humidities in Meyers (1951), Mitchell (1953), Dettling (1962) and Grasley and Lange (2007) showed a convex shape (bell-shape) when CTE was plotted as a function of relative humidity. This convex shape of CTE was attributed to the convex shape of the hygrothermal coefficient (Grasley and Lange 2007;Wang et al 2018), which is defined as the change of relative humidity inside a sealed sample per temperature change under constant water conditions.…”