The effect of the drying temperature on water porosity and gas permeability of recycled sand mortar

摘要

The main purpose of this study is to determine the effect of the drying temperature on the durability indicators such as water porosity and gas permeability of mortar made of recycled sand. A relationship between experimental parameters such as mass loss and water absorption and durability indicators has been established. Mortars made of recycled sand (M-RS) and natural sand (M-NS) were fabricated and then tested after a pre-treatment at different temperatures (60 degrees C, 80 degrees C and 105 degrees C). Water porosity and gas permeability were determined then at each temperature range (60 degrees C, 80 degrees C and 105 degrees C) using the same specimen. Results show that the increase in the drying temperature from 60 degrees C to 105 degrees C does not influence the water porosity of M-RS as much as the gas permeability. Second, the increase in the gas permeability with the drying temperature is not only due to the water evaporation but also to the micro cracks created during the drying process. Finally, pre-treating samples at 105 degrees C as suggested by the standard methods affects the microstructure of M-RS and leads to false results: a pre-treatment temperature of 60 degrees C is more appropriate in the case of mortars made of RS. (C) 2019 Elsevier Ltd. All rights reserved.