Fluid ingress is a primary factor that influences freeze-thaw damage in concrete. This paper discusses the influence of fluid ingress on freeze-thaw damage development. Specifically, this paper examines the influence of entrained air content on the rate of water absorption, the degree of saturation, and the relationship between the saturation level and freeze-thaw damage. The results indicate that whereas air content delays the time it takes for concrete to reach a critical degree of saturation it will not prevent the freeze-thaw damage from occurring. The results of the experiments show that when the degree of saturation exceeds 86–88%, freeze-thaw damage is inevitable with or without entrained air even with very few freeze-thaw cycles.

In service, concrete can develop cracks or microcracks that can influence the transport of liquids and ions. This paper describes an investigation of fluid transport in concrete damaged by tensile loading or freeze–thaw cycling. Acoustic emission was used to quantify the extent of damage in the specimens exposed to tensile loading while resonant frequency was used to quantify the extent of damage in the specimens exposed to freezing and thawing. Water absorption was measured in the damaged concrete. The presence of freeze–thaw damage increased both the initial sorptivity and total water absorption. Electrical conductivity was measured and found to increase in a bilinear fashion with freeze–thaw damage. A knee point in the electrical conductivity versus freeze–thaw damage curve was observed when the dynamic modulus degraded to 75% of its initial value, which appears to correspond with the coalescence of cracking. Mechanical loading was found to only increase water absorption on a local level, but it did no...

Electrical properties are frequently measured in the concrete construction industry as a part of mixture qualification and quality-control testing. Whereas there are several factors that influence the electrical response of concrete, one of the most important factors is its degree of saturation. Although current standard tests rely on the concrete’s being saturated, this can be difficult to accomplish, is time-consuming, and can artificially increase the degree of hydration of the test sample in comparison with that of concrete in field structures (when the test samples are stored in water). Although some studies have measured the electrical response of concrete for samples with different moisture content (i.e., stored at different relative humidities), a single expression has not been proposed that predicts how drying changes the electrical response. This paper suggests that a saturation function should be considered as a possible method to account and to correct for less than complete saturation...

This paper investigates the potential use of phase change materials (PCM) in concrete pavements to store heat, which can be used to reduce ice formation and snow accumulation on the surface of the concrete pavement. The thermal properties of the PCMs are evaluated using a low-temperature differential scanning calorimeter (LT-DSC) while a longitudinal guarded comparative calorimeter (LGCC) is used to evaluate the thermal response of cementitious mortar containing the PCM. Paraffin oil (petroleum based) and methyl laurate (vegetable based) were selected as PCMs since they have high enthalpies of fusion ($\sim 130–170\mathrm{J}/\mathrm{g}$ ) and have desirable freezing temperatures ($\sim 2–3°\mathrm{C}$ ) during the liquid to solid phase transformation. Two approaches were used to place the PCM in the mortar specimens: (1) placing the PCM in lightweight aggregate (LWA) in mortar and (2) placing the PCM in an embedded tube that is placed in mortar. The durability and stability of the PCMs in the cementitious system were studied by monitoring the change in enthalpy of fusion, mass loss, pulse velocity, and compressive strength. When the PCM was placed in the mortar specimen using LWA, the paraffin oil can release a considerable amount of heat during phase transformation, which can be used to melt ice and snow. However, it was observed that the methyl laurate reacts with the cementitious matrix, causing damage to the mortar. Both paraffin oil and methyl laurate showed promising performance to melt ice and snow when the PCM was placed in an embedded tube in the mortar specimen.