Experimental research on using diatomite aggregate in hollow masonry blocks for bushfire resistance

Abstract

Purpose – This paper investigates the influence of using a lightweight aggregate called “Diatomite” in hollow masonry (i.e. cement) blocks for bushfire resistance. Design/methodology/approach – One of the 100-block series category (i.e. 90 mm thick) hollow masonry blocks were fabricated using a diatomite fine aggregate-based cement mix (i.e. cement-sand-diatomite mix). Properties of the mixed ingredients were determined, and the cement-sand-diatomite mix were developed based on the absolute volume method. After 28 days of curing, tests were conducted on hollow blocks, including density, compressive strength, bushfire and building fire resistance, and the results were compared with those of the cement-sand (standard) mix hollow block and one of the commercially available hollow blocks. Findings – The newly developed diatomite mix hollow block satisfies the density requirement for ultra-lightweight masonry units and the strength requirement for loadbearing hollow masonry units. It is the only block that complied with the temperature limit for unguarded interior surfaces of bushfire shelters and showed one-hour additional building fire resistance (−/120/120) than that of cement-sand mix (−/60/60) and commercial hollow blocks (−/60/60). Practical implications – The diatomite mix hollow block developed in this research can be suggested as a suitable loadbearing lightweight hollow masonry block for bushfire shelters and external walls of the buildings in bushfire-prone areas. Originality/value – Limited studies are available for hollow masonry blocks in relation to their bushfire and building fire resistance.