Cement-Biofouling and Sulfate Resistivity of Hardened Blended Cement Pastes in Marin Environment: A Case Study

In the present study, field examinations are explored on diversed blended cement mixes. The hardened blended pastes are prepared using ordinary Portland cement (OPC), fine metakaolin (MK) and brine chlorine sludge(CLS). Cement fouling features and the attack by SO4-2 ions are studied on the blended samples that are immersed in the sea water for 9 months. The performance of the cured specimens was explored via studying the compressive strength, the percent of mass change and the volume expansion at various curing durations. Besides, the total chlorophyll colonized on the surface of the cured specimens was determined by using spectrophotometeric technique. XRD and SEM techniques are specifed for studying the phase compositions and the morphology of the formed cement hydrates. The results illustrate that the blended mixes show an antifouling behavior higher than the neat OPC. This is related to acquiring a more compact structure of reduced porosities upon OPC blending. Additionally, OPC-MK specimens showed higher SO-42 ions resistance than OPC-CLS or OPC pastes. This is related to the high pozzolanic properties of MK in contrary to brine sludge.