Influence of expanded vermiculite powder and silica fume on properties of foam concretes

Abstract

This study focuses on production of foam concrete that presents thermal insulation property. Foam concretes were produced using cement, expanded vermiculite powder, silica fume and the generated foam. Foam agent, which was protein based, was utilized to obtain foam having different concentrations. Cement content was used between 356 and 643 kg/m3. The foam concretes were cast into the moulds with a size of 200 × 200 × 500 mm prism and cylinder with Ø150 × 300 mm. Viscosity, fresh and dry unit weights, water absorption, ultrasound, compressive strength, capillarity and thermal conductivity tests were achieved. Foam concretes were kept in laboratory ambient temperature and subjected to 300 °C. A scanning electron microscope (SEM) images were also obtained for observations of microstructures of specimens. As a result of the study, foam concretes having different compressive strengths of 0.4–3.7 MPa, dry unit weights of 587–1040 kg/m3, thermal conductivities of 0.059–0.237 W/mK and porosity of 70.6%-89.5% were obtained. Test results were discussed considering the effects of foam concentration and elevated temperature and also compared to the results in the literature in detail. Foam concretes with expanded vermiculite powder presented promising results in point of thermal conductivity.