The Effect of Hydrophobic Amorphous Carbon Powder on the Compressive Strength, Water Absorption and Rheological Attributes of Cement Mortar

In this paper, the feasibility of employing amorphous carbon powder as a viable degradation inhibitor for cement mortars made with siliceous aggregates was investigated. Amorphous carbon powder is a by-product of the paraffin industry and was replaced by 0, 4, 6 and 8% of aggregate. Mechanical strength, rheology and water absorption were analyzed considering three common physical factors of concrete namely strength, workability and durability. Mechanical properties of mixtures were obtained using flexural and compressive strengths and rheological attributes were collected through flow table test. Results revealed that adding amorphous carbon powder to the bulk cement mortar could enhance the strength and durability of cement mortar. Replacing 8 wt.% of siliceous aggregate dust filler by amorphous carbon powder caused an increment about twofold in the 28-day compressive strength and reduction of the flow table results by about 20% compared to those of the control mixture. Moreover, hydrophobicity and impermeability properties of amorphous carbon -modified cement mortars, resulted in reduced moisture susceptibility.