Durability and morphological assessment of concrete manufactured with sewage

•Using sewage to build concrete specimens increased the water absorption, water penetration contents and charge passed as well as decreased compressive strength, particularly in higher ratios of water-cement.•Concrete specimens produced from sewage had heterogeneous and porous structures, unlike the control samples built by potable water, which results were in line with MIP test.•A lower resistance under cycles of freezing and thawing was observed in the utilization of sewage.•A hundred combined cycles of freezing and thawing with sulfate attacks accelerated the concrete deterioration and caused to striking declines of compressive strength. The effects of using potable water or sewage on the durability parameters of concrete with three water-cement ratios (0.4–0.6) were evaluated through the experimental tests. The results showed that using sewage caused a rise of water absorption, water penetration, and charge passed as well as decrease of concrete compressive strength, particularly in higher ratios of water-cement. Besides, the surfaces of concrete specimens produced from sewage were heteronomous with numerous cracks and pores, whereas the concrete surfaces in using potable water were monolithic with fine crystals and gels, which are in line with the mercury intrusion porosimetry test that showed higher porosity. The results of simple freezing and thawing cycles indicated that utilization of sewage decreased the concrete compressive strength, which these amounts fell by raising the water-cement ratio and number of cycles. In lower number of cycles of combined freezing and thawing with sulfate attacks, the concrete compressive strength in application of potable water and sewage increased, which can be a result of producing ettringite strings in the concrete inner spaces. In contrast, the greater number of combined cycles speeded up the deterioration of structures of concrete samples, and these simultaneous effects progressively decreased the concrete compressive strength approximately two times more than simple freezing and thawing cycles. Furthermore, more decreases of compressive strength were observed in the concrete specimens produced from sewage.