Road Concrete Containing Coal Ashes of Thermal Power Stations Located in Krasnoyarsk

Abstract

The paper reports on outcomes of research into a road concrete containing coal ash powders of thermal power stations located in Krasnoyarsk. The study was focused on characteristics of a fly ash, and ash taken in an ash-disposal area of Krasnoyarsk Thermal Power Station 1, as well as ash of Beryozovskaya GRES. To compare characteristics a standard limestone powder was used. Physical and mechanical characteristics, chemical and mineral composition of these powders were analyzed. Mineral powders differed in a concentration of free calcium oxide (СаОfr.). Samples of a fine-grained road concrete were composed and prepared using materials above. Physical and mechanical properties of formed road concrete samples were tested. A coefficient K was introduced to assess the relation between key characteristics of a road concrete mix and concentration of free calcium oxide, furthermore, it considers a percentage of СаОfr. in ash (m) and percentage of this ash in a road concrete (n), i.e. К= m·n. It has been established a coefficient К ranging 0 to 32 СаОfr. has no significant effect on characteristics of a road concrete mix. A fly ash and ash taken in an ash-disposal area of Krasnoyarsk thermal power station 1 are recommended for the use in industry as a mineral powder in a road concrete mix. Additionally, ash taken in an ash-disposal area is to be dried and grinded, a maximal content of a fly ash in a road concrete mix is estimated to be 4% provided that a concentration of СаОfr. is less than 8%.