An Early-age Evaluation of Thermal Cracking Index of Heavy Concrete Applying for Airport Pavement

Abstract

Industrial waste management has been an integral part of many countries in the world, including in Vietnam. In which, bottom ash (BA) has been used as a pozzolanic additive in compositions of the heavy concrete applying for airport concrete pavement (ACP), which allows reducing the hydration heat, the cost, and the thermal cracking of the concrete during the construction process. The purpose of this study is to summarize the experimental laboratory results of the heavy concrete samples containing 35 % BA sourced from a thermal power plant in Vietnam. The mechanical and thermal properties of the heavy concrete samples were determined at different curing ages. Besides, the heat of cement hydration during the preparation of the heavy concrete in the laboratory was measured using a "TAM AIR" isothermal calorimeter. Moreover, the Midas civil computer software based on the finite element method was used to analyze the temperature field and thermal cracking index of the ACP at the early ages. As the results, the heavy concrete had the respective thermal conductivity and the average of specific heat of 1.1 W/(m.°C) and 878.35 J/(kg.°C). Moreover, the value of thermal cracking index indicates that no cracking occurred on the ACP at the early ages. Furthermore, the results of the present study can be considered as a useful reference source for future projects that are associated with the construction of the ACP.

Structural Performance Assessment of Airfield Concrete Pavements Based on Field and Laboratory Data

“…Contrariwise, thermal cracking on concrete pavements usually occurs at new pavements shortly after their construction [19]. These early-life cracks appear when the tensile strain formed from restrained thermal contraction or temperature differentiations exceeds the tensile strain capacity of concrete [18,20]. In addition, construction activities during summer months under high environmental temperatures cause quicker water evaporation leading to concrete shrinkage phenomena [20].…”

“…These early-life cracks appear when the tensile strain formed from restrained thermal contraction or temperature differentiations exceeds the tensile strain capacity of concrete [18,20]. In addition, construction activities during summer months under high environmental temperatures cause quicker water evaporation leading to concrete shrinkage phenomena [20]. In a related study for highway pavements, it has been reported that shrinkage cracks reduce tensile strength in the surface by around 50%, and although they do not initially produce visible cracks, they can intensify crack opening after the pavement is exposed to traffic loadings [21].…”