Shrinkage behavior of autoclaved aerated concrete containing calcined diatomaceous earth as the main silica raw materials at various autoclaving temperatures

Abstract

AbstractIn previous studies, calcined diatomaceous earth (DE) was used as the main silica raw material within the mixture of autoclaved aerated concrete (AAC) to produce DE‐based AAC. Compared to the quartz‐based AAC autoclaved at 192°C, the DE‐based AAC autoclaved at 165°C exhibited, a 57% higher compressive strength and a 54% higher A‐value. In this study, the values of total drying shrinkage are presented in order to complete the results reported in previous studies. According to the results obtained in this study, for AAC with calcined DE, a decrease of 27% in the total value of drying shrinkage was observed as the autoclaving temperature was adjusted to 165°C instead of 192°C. This observation was in opposition to the behavior of AAC with quartz sand which its total value of drying shrinkage increased by 59% when the autoclaving temperature was set to 165°C instead of 192°C. However, in general, a higher total drying shrinkage was observed for the DE‐based AAC autoclaved at 165°C compared to that for the quartz‐based AAC autoclaved at 192°C. The reason could be due to the higher portion of capillary pores and non‐crystalline C‐S‐H as a result of replacing quartz sand with calcined DE within the AAC mixture.