Mortar using the reforming recycled fine aggregate treated with fluosilicic acid

摘要

The present invention relates to a modified fine recycled aggregate processed with fluorosilicic acid, to lower strong alkalinity, which is pH 11 to 13, caused by calcium hydroxide of mortar or paste attached on a surface of recycled aggregate produced by recycling of used concrete; a manufacturing method thereof, and a mortar using the modified fine recycled aggregate manufactured thereby. According to the present invention, recycled fine aggregate with a particle size of 5 mm or less is precipitated in a neutralization tank processed by fluorosilicic acid to neutralize the aggregate between pH 6.5 to 10 so as to realize pH reduction; the fluorosilicic acid is reacted by an agitator to inhibit a continuously eluted alkali material while modifying the aggregate through a chemical reaction and a pilling action with the calcium hydroxide in the paste on the surface of the recycled fine aggregate; and a chemical reaction generating CaF_2 and SiO_2, which are inorganic powder, is accompanied as the calcium hydroxide reacts with the fluorosilicic acid; and such reaction is gradually advanced towards the inside from the surface of the recycled fine aggregate so as to realize absorption rate reduction. Thus, provided are effects capable of: ensuring a high quality recycled fine aggregate; using the fluorosilicic acid with the strong alkalinity generated or produced as a by-product during processing and manufacturing processes of phospho-gypsum, phosphatic fertilizer, and the like, so as to reduce costs in comparison with the case that an expensive material, such as acetic acid, phosphoric acid, etc., is used, thereby enhancing economic efficiency; and not adversely affecting an ecosystem as processing water of the neutralization tank is neutralized, thereby being able to be environmentally-friendly used.