Synergistic effect of dry sludge from waste wash water of concreteplants and zeolitic by-product on the properties of ternary blendedordinary Portland cements

Abstract

This paper analyses the use of two types of supplementary cementing materials,edry sludge from wastewash water of concrete plants and zeolitic by-productefor producing hardened cement paste speci-mens. X-ray powder diffraction, scanning electronic microscopy, energy-dispersive X-ray spectroscopy,and thermal analysis were used as investigation methods. Test results showed that the addition of drysludge reduced the compressive strength of hardened cement paste at both 7 and 28 days. In hardenedcement paste specimens where Portland cement was substituted with 5 %e30% of dry sludge thecompressive strength decreased significantly after 7 and 28 at days. After 28 days blended Portlandcement containing up to 10% of supplementary cementing materials ((SCM) - dry sludge and zeolitic by-product) demonstrated higher compressive strength than the reference specimen as a result of syner-gistic interactions, whereas higher replacement levels led to reduction in compressive strength.