Properties of alkali-activated lightweight concrete

Abstract

This chapter presents a brief overview of the properties of alkali-activated lightweight concrete. Nowadays, the production of lightweight concrete has great attentions due to its extraordinary advantages such as reduced mass, improved sound and thermal insulation properties. Furthermore, the low gas emissions and the utilization of waste materials increase the importance of alkali-activated lightweight concrete. In this chapter, the strengths of lightweight concrete were examined by considering the aggregate type and density, the alkali activator type and concentration, the type of fiber reinforcements and foaming agents, which are the factors that have the most impact on the strengths. Thermal conductivity, fire resistance, acoustic performance, and durability properties have been explained considering the key points in the literature. In addition to porosity, it has been determined that one of the most important factors directly affecting the fire resistance is the precursor type. It has been concluded that the fire resistance of the concrete prepared by using K-based precursors is higher. Acoustic performances of alkali-activated lightweight concrete vary. It is necessary to use a high amount of aggregate in order to obtain concretes with wide frequency ranges and high absorption coefficient. Contrary to concrete produced from Portland cement, alkali-activated concrete is more resistant to acid and sulfate attacks, since the formation of gypsum and strength is less.