Testing and modelling of hygro-thermal expansion properties of concrete

This paper investigates the hygro-thermal expansion behavior of concrete as a function of the internal temperature and humidity changes caused by thermodynamics and moisture diffusion. The effects of age and moisture on the Coefficient of Thermal Expansion (CTE) of concrete were evaluated by measuring the temperature, humidity, and strain of cylindrical and prismatic concrete specimens. Based on the measurements, the effects of age and moisture on the concrete CTE were analyzed. In addition, CTE, which depends on moisture, was modeled and validated by comparison with existing research results. The study results indicate that the effect of age on concrete CTE is not significant. CTE was maximized at a concrete humidity of 85% and was about 1.6 times larger than the minimum CTE measured at a humidity of 95~100% or below 50%. The hygro-thermal model developed in this study predicted the measured CTE reasonably well. The CTE of a concrete slab is an important parameter in the design of concrete pavement. More accurate design methodology can be implemented by including the effect of moisture on CTE.