Composite binders from industrial waste

Abstract

The relevance of involving industrial waste in the production of building materials, in particular for the production of composite binders, is noted. The results are presented: the results of using pumice slag waste, cupola slag, fuel slag, ash for the production of composite binders; Theoretical foundations of the formation of the structure of finely divided sodium silicate composition from anhydrous sodium potassium silicates and industrial wastes. The results of experimental studies have shown that the basic properties of a composite binder can be controlled by changing a number of technological factors, such as the sodium silicate content in the composition (20-30 mass%), the fineness of the components (2000-2500 cm2/g), the amount of mixing water (17-20%), the degree of compaction of the mixture, the use of one or another fine-ground waste. The astringent properties of these compositions are manifested mainly due to the adhesion properties determining the adhesive ability of this component by anhydrous sodium silicate and potassium silicate. The cohesive strength of adhesive contacts, strength and durability, in turn, depends on the conditions of their formation. It was found that when the composition is heated in the temperature range 90-100°C, the most intense surface dissolution of the silicate block grains occurs and, as a result, the adhesive contact area increases. A subsequent increase in temperature to 180-200°C leads to an almost complete dehydration of the system and its hardening, due to a sharp increase in the cohesive strength of the adhesive contacts. Sufficiently high physical and mechanical properties of composite binders developed from waste materials (fly ash, fuel slag, cupola slag, pumice slag) suggest that light concrete can be made on their basis by introducing various types of porous granular heat-insulating materials as filler (expanded clay, agloporite, granulated slag, expanded perlite, etc.). Experimental studies have shown the possibility of obtaining from virtually any type of waste composite binders on anhydrous sodium-potassium silicates (silicate block). The astringent properties of these compositions are manifested due to the acquisition of anhydrous sodium-potassium silicate adhesive properties that determine the adhesive ability of this component, and the cohesive strength of adhesive contacts, the strength and durability of which, in turn, depends on the conditions of their formation.