Properties of foam concrete produced from base ash and recycling aggregate

To follow resource conservation, the production of optimized and sustainable structures through the use of insulating materials such as foam concrete has become a trend in construction industry. Although foam concrete has numerous benefits, the larger use of Portland cement in its mixture and its relatively low thermo-durability properties due to the low content of solid materials are major concerns. In that respect, this study evaluates the use of recycled fine concrete aggregate, limestone and bottom ash sand as main aggregate materials to evaluate the physico-mechanical and thermo-durability properties of foam concrete. To that end, 25 mixes have been produced and a comprehensive series of tests including flowability, compressive and flexural strength, water absorption, apparent porosity, drying shrinkage, sorptivity, abrasion resistance, thermal conductivity as well as the effect of elevated temperature and its respective cooling regime on foam concrete have been conducted in this study. On this basis, it is found that foam concretes manufactured with bottom ash and recycled fine aggregates develop a considerably lower thermal conductivity values despite being outperformed in physico-mechanical properties by those mixes produced with limestone sand. Nonetheless, the inclusion of bottom ash sand is found to produce foam concretes with a comparable physico-mechanical and thermo-durability properties to mixes with limestone. The results of this study are significant and point to the suitability of utilizing alternative fine-sized aggregates such as recycled fine aggregate and bottom ash sand for the production of foam concrete without compromising the insulating properties. KEYWORDS: Foam concrete, Lightweight concrete, Recycling aggregate, Bottom ash sand