Enhancement of alkali-activated slag cement concretes crack resistance for mitigation of steel reinforcement corrosion

Abstract

The paper is devoted to mitigation of steel reinforcement corrosion in alkali-activated slag cement (further, AASC) concretes, based on soluble sodium silicates (further, SSS's), obtained from high consistensy concrete mixes. Enhancement of AASC fine concretes crack resistance due to modification by complex shrinkage-reducing additives (further, SRA's) based on surfactants and trisodium phosphate Na3PO4 . 12H2O (further, TSP) was proposed for mitigation of steel reinforcement corrosion. SSS's were presented by sodium metasilicate (silica modulus 1.0, dry state) and water glass (silica modulus 2.9, density 1400 kg/m 3 ). In case of sodium metasilicate the application of SRA composition "ordinary portland cement clinker -TSP -sodium lignosulphonate -sodium gluconate" provides enhancement of crack resistance starting from early age structure formation with restriction of drying shrinkage from 0,984 to 0,713 mm/m after 80 d. The effect is caused by reduction of water and by higher volume of crystalline hydrates. In turn, SRA presented by compositions "TSP -glycerol" and "TSP -glycerol -polyacrylamide" provide enhancement of AASC fine concretes fracture toughness during late structure formation with increasing ratio of tensile strength in bending to compressive strength up to 37 -49 % if compare with the reference AASC when water glass is used.

Research activation energy in thermal modification of wood

“…Knowledge of physical and chemical properties of substances such indicators of quality, the mechanism of action of the materials allows you to make their choice on the basis of economic performance, duration and application security, environmental aspects, etc. [2,3]. And the application allows protection to maintain their function when operating within a specified period of time [4][5][6].…”

Properties of Concretes Incorporating Recycling Waste and Corrosion Susceptibility of Reinforcing Steel Bars

“…Ground granulated blast furnace slag has begun to be used widely since the discovery of its latent hydraulic properties. Many researchers have been conducting lots of experiments to determine the properties of cements and concretes containing GGBFS and fly ash [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. According to Ivashchyshyn et al [ 15 ] and Kurdowski [ 22 ], properties of cements and concretes containing blast-furnace slag depend on the chemical composition, fineness of slag, and the amount of vitreous structure in slag.…”

Study of influence of alkaline component type on pH value and properties of alkali activated concretes containing basalt rock

“…Nowadays a question of widening of raw materials base became very sharp [1][2], including materials for cement and concrete production [3][4][5]. Permanent rising of prices on traditional high-quality aggregates leads to the search of chipper ones, but at the same time the less qualified materials [6][7][8]. Between aggregates in this category there is a high possibility to have active grains (active silica) , able to participate in reaction with cement matrix and leading to the problems [12][13][14], some times -technogen accidents [15][16][17].…”