Use of sewage sludge ash(SSA)-cement admixtures in mortars

The chemical composition of sewage sludge ash (SSA) and their sized fractions are studied, some differences in chemical composition are observed. SEM studies show irregular shape of SSA particles and sized fractions, this shape has a decisive influence on workability of mortars. The effect of replacing 15% of portland cement by SSA and their sized fractions: coarse (SSAC) and medium (SSAM) obtained by sieving on compressive (R c ) and flexural (R f ) strength of mortars was investigated. The study reveals an enhancement of strength when ashes are used, due to probably, pozzolanic properties of SSA.