Effects of sulfuric acid attack on hydrated calcined clay–limestone cement mortars
Joseph Mwiti Marangu
Abstract
The paper presents experimental findings on the performance of Limestone Calcined Clay Cement (LC3) in acidic media. LC3 was made by inter-grinding a blend of 50 % clinker with ground 30 % Fired Rejected Clay Bricks (FRCB), 15 % limestone and 5 % gypsum. Compressive strength and water absorptivity of LC3 mortars were investigated vis-à-vis commercial Ordinary Portland Cement (OPC) and Portland Pozzolana Cement (PPC). Microstructural analysis of hydrated LC3 samples was conducted using Scanning Electron Microscope (SEM) before and after immersion in 3% H2SO4. LC3 reported the least water absorptivity than PPC and OPC. Additionally, LC3 exhibited equivalent water absorptivity and resistance to acid attack compared to PPC. Micro-cracks were observed in SEM images from LC3 samples after immersion in acid. In conclusion, strength loss, at w/c = 0.50 and 0.60, LC3 exhibited 12.71 % and 14.06 % respectively, higher resistance to acid attack than OPC.