Title: Study of the Compositions and Properties of Secondary Mineral Resources for Developing the Heat-Insulating Concrete not Containing Portland Cement
Author(s): A. G. Tuleyev, S. I. Pavlenko, K. V. Eryomkin, N. L Dobretsov, and K. Freidin
Publication: Symposium Paper
Appears on pages(s): 617-632
Keywords: air entraining admixture; fly ash; granulated slag; heat-insulating concrete
The materials used for the investigation were fly ash and granulated slag from the Yurga thermal power plant used up molding sand from the Yurga machine building plant and the high alumina product (HAP) from the Yurga abrasion works. The bulk density, the absolute density and the surface area of the fly ash were 1150 to 1200, 2800 to 2850 kg/m3 and 300 to 310 m2/kg, respectively. To enhance its binding properties, it had to be ground. According to its chemical analysis (31.73% free CaO, 1.87% S03,1-06% LOI), the ash was high-calcium. It had a good binding properties with the more than 1: Cq=CaO+MgO+Al2O3/S'02. Slag sand of 0.14 to 5 mm particle size from its chemical analysis met the State Standard requirements for use as an aggregate. There was very little loss on ignition. The burnt sand was composed 92% quartz sand, 6% bentonite clay and 2% liquid glass. After being used in foundry and removing of gritty scale, it had the form of black sand with the fineness modulus, bulk density and absolute density being 1.91, 1450 and 2380 kg1m3, respectively. The burnt sand had a high content of SiO2 in the amorphous state. Very little loss on ignition was observed which increased the feasibility of chemical binding free CaO into calcium silicates. The high alumina product was a powder containing above 88% Al2O3. The radionuclides contents of all the materials used was 3 to 5 times lower than the standards. By grinding the three components (fly ash, burnt sand and HAP) in a planetary mill a new binder not containing portland cement was obtained. In the process of grinding, the mechanochemical activation of the components as well as the interaction of the amorphous silica and HAP with free CaO took place. The compressive strength of the binder was 50 to 60 MPa. The study of the secondary resources permits the developing on their basis of a high-performance heat-insulating not containing portland cement concrete using the air-entraining admixture and the slag sand as an aggregate.