Influence of microstructure on fluid transport and mechanical properties in structural concrete produced with lightweight clay aggregates

The use of lightweight aggregates (LWA) in concrete is an interesting alternative to simultaneously reduce the total structure weight and provide both appropriate resistance and concrete's performance. This paper studies the influence of LWA on concrete, comparing the changes in the mechanical properties, pore structure and fluid transport related to the increase of LWA content. Results reveal that although LWA reduces the mechanical properties of the studied samples does not significantly affect the fluid transport properties. Total porosity rises with LWA content whereas open porosity remains nearly invariable. LWA pores do not totally participate in the fluid transport through the concrete and, consequently, fluid transport through lightweight concrete is limited by the continuity and accessibility of the LWA pores and is dominated by the properties of the mortar matrix.