Effect of Silica fume and Ultra Fine Filler on Acid Resistance of Concrete

Biogenic sulfuric acid corrosion is often a problem in sewer environments. Also in certain industrial activities sulfuric acid is used during the production process. it can lead to a mst degredation of the concrete structures. Therefore, there is a substantial need for construction of durable concrete structures in such environments. The porosity of concretes plays an important role in harsh environments. For production low porosity or high density concretes, optimization of aggregate and cement grading and their proporations is necessary. The size distribution of aggregates and cement materials determine the compactIbility and highest local density of particles. Dense packing of concrete particles in the mixes lead to low cement content and high-strength of low porosity mortar and concretes.A research program was undertaken to improve concrete resistance against sulfuric acid attack. Three concrete mixtures were investigated, the first mix contained Type 2 Portland cement and the second one contained Type 2 Portland cement and super fine Quartz powder as a filler with a particle size of 0 to 16 micron. The third mix contained Type 2 Portland cement with 8% silica fume (SF) replacement and super fine filler. The dense packing of siliceous aggregates and cement materials were used to achieve the highest density of concretes. Fuller ideal grading curve for particle size distnbution (pSD ) of the cement material was used. The PSD of the Quartz powder, silica fume and cement was anlayzed to explain the packing effect of super fine Quartz powder. Cement content and water cement ratio varied in this investigation. tn the experiment, concrete cubes and mortar plates were immersed in sulfuric acid with pH= 1.0. They were periodically examined for appearance, measured for mass change and tested in compression and flexure up to 90 days. The performance of mortar and concretes containing silica fume and ultra fine filler was better than the control mix.

Effect of Silica fume and Ultra Fine Filler on Acid Resistance of Concrete Keywords:

Dense packing , Porosity , Silica fume , Sulfuric acid attack , Ultra fine filler