Experimental investigations on water absorption and mechanical properties of expanded perlite mortar under accelerated and natural aging conditions

Abstract

The objective of this paper is to study the variation in the physical and mechanical properties of expanded perlite mortar with environmental factors and analyze its deterioration mechanism. In this paper, the influence of the heat-rain cyclic and natural aging on the physical and mechanical properties of expanded perlite mortar has been studied. The expanded perlite mortar specimens were subjected to 80 heat-rain cycles (the maximum temperature rises to 70℃, and the spray volume reaches 1 L/(m² min)) and 60-day natural aging tests (the daily average temperature is 23°C, with the maximum temperature reaching 36°C). The corresponding mass loss rate, water absorption, and compressive strength of the specimens at every 10 heat-rain cycles and 10 days were determined. The results show that the mass loss rate gradually increases with the increase in heat-rain cycles and the natural aging days. The variation range was found as about 0.2%~0.7% and -0.4%~0.2%, respectively. The water absorption rate gradually decreases with the number of heat-rain cycles and natural aging days; however, the decay rate of the water absorption rate differs by orders of magnitude in the two weathering conditions. The compressive strength does not have an obvious change with the number of heat rain cycles, but it first increases and then decreases with the number of natural aging days. Under artificial and natural aging, the deterioration mechanism and aging speed of expanded perlite mortar are much different. The comparative analysis of the physical and mechanical properties of expanded perlite mortar under artificially accelerated and natural aging conditions can further reveal its evolution model and the corresponding relationships under the two conditions and provide a theoretical basis for establishing a more scientific and reasonable aging system.

Behaviour of sewage sludge based lightweight aggregate in geopolymer concrete

“…Out of all the natural aggregates, only pumice is used widely. The lightweight property of these rocks is due to the escaping of gas from the molten lava which erupts from beneath the earth's crust [12,13]. Artificial LWA is made up of waste materials, such as fly ash, metakaolin, or volcanic ash, and ground granulated blast-furnace slag (GGBS) [14].…”