Effect of Combined Coal-Biomass Ash on the Chloride Penetration Resistance of Mortar Cement: A Case Study of Different Anthracite, Bituminous, Rice Husk and Eucalyptus Ash Exposed to Synthetic Seawater

Abstract

Abstract

This article presents the study results of durability of chloride attack in chloride penetration of mortar mixed with (Combined Coal-Biomass Ash, CBA) obtaining from thermal power plants at which have been burnt with fuel with specific proportions of anthracite : bituminous : Rice husk : eucalyptus bark by mass percent as follows: 50.9 : 36.8 : 7.4 : 4.9 (assigned as Type A), 77 : 0 : 16.9 : 6.1 (assigned as Type B) and 0 : 0 : 60 : 40 (assigned as Type C). The as-received CBA was ground by a Los angles grinding machine until having specific surface areas in term of Blaine fineness equal to 6260, 6700 and 6300 cm2/g, respectively. It was then partially replaced by mass in Type 1 Portland cement at percentage replacements of 15%, 30% and 45%. A case study of chloride attack was the immersion in synthetic seawater prepared with a concentration of 0.45 mol/L chloride and a 0.03 mol/L sodium sulfate (Na2SO4). The water-powder by mass ratios (w/p) of 0.45, 0.55 and 0.65 were controlled and also compared to chloride-resistant Portland cement. Test results, it was indicated that the chloride penetration of mortars mixed with CBA tends decreasingly when increasing the amount of CBA. Mortars containing Type C ash has lower chloride penetration than those of types A and B ash mortars. Further at a 30% replacement of every ash, mortars have also lower than those of other replacements.

Keywords : Coal ash; Biomass ash; Mortar cement; Durability; Chlorid; Synthetic seawater.