Preparation of bittern-resisting cement used by fly ash

Liang

et al. 2011

AMR

Cemented filling body exposed to acid mine water or high salinity mine water will be subjected to various kinds of physical and chemical attack. In this paper, the burning process of a modified special cement clinker used for corrosion-resisting cementitious material in fill mining is studied by means of TG-DTA, XRD, and chemical method. The main minerals of this kind of clinker are C3S, C2S, C4A3, and C4AF. The optimal firing temperature range of the clinker is from 1300°C to 1380°C, and a suitable amount of F- and SO3 in raw meals is helpful to the coexistence of C3S and C4A3in the clinker.

Section: Introductionmentioning

confidence: 99%

Studies on Burning Process of Clinker Used for Corrosion-Resisting Cementitious Material in Fill Mining

Liang

et al. 2011

AMR

“…Although many theories are put forward for the purpose of improving the durability of concrete in such areas, from the long-term point of view, the most effective way to solve the durability problem in high-bittern environment is to research and develop a special kind of cementitious materials which could resist such physical attacks or chemical corrosion. Bittern-resisting cement (BR) is a new kind of cement prepared for high-bittern environment, which is composed of Portland cement clinker containing C 4 A 3 S phase, high-activity ground granulated blast-furnace slag (GGBFS) and fly ash (FA) in a ternary cementitious system [6,7]. This kind of cementitious materials can result in increasing the early strength and long-term strength, reducing the possibility for the formation of harmful products such as gypsum and ettringite, densifying the microstructure and improving chemical stability because of pozzolanic reaction and dominant complementation effect of mineral materials among slag, fly ash and cement clinker.…”

Section: Introductionmentioning

confidence: 99%

Durability of Bittern-Resisting Cement in High Concentration Brine

Hou

Zhai

et al. 2011

AMR

Bittern-resisting cement (BR) has more excellent performance to resist physical attack and chemical corrosion in high-concentration brine environment than ordinary Portland cement or sulfate- resisting Portland cement. The durability and chemical stability of bittern-resisting cement are studied under drying-wetting cycles in brine, the microstructure and chemical component of hydration products also are determined by SEM/EDXA. The corrosion resistance coefficient Kf of BR mortar prisms in high-concentration brine for 6 months is over 96%, and the mass loss of mortar prisms after 30 drying-wetting cycles in brine is only 4.3%. SEM/EDXA analysis shows that the microstructure and chemical composition of BR hydration products exposed to high-concentration brine environment is more densely and stable than those of ordinary Portland cement.

Int J Applied Ceramic Tech

Novel Utilization of Fly Ash for High‐Temperature Mortars: Phase Composition, Microstructure and Performances Correlation

Terzić

Pavlović

Radojević

et al. 2013

In this study, the feasibility of using fly ash to manufacture high‐temperature mortars was investigated. The investigation was set to define preliminary characteristics of new types of mortars based on ordinary and/or refractory cement with fly ash addition, and to establish mutual correlation between thermally induced changes of mineral phases, microstructure, and final performances of the mortars. New mortars, made up of 21% cement (PC‐CEM I 42.5R/HAC‐Secar 70/71), 70% river sand, and 9% fly ash, were chemically, physically, and mechanically characterized to determine possibilities of fly ash re‐utilization for high‐temperature purposes. The fly ash samples, which originated from four different power plants, were mechanically activated. Mortars were heat‐treated up to 1300°C in a laboratory tunnel furnace with retention time 2 h. Thermal stability of crystalline phases were studied by differential thermal analysis (DTA); thermally induced changes in mineral phase composition were analyzed by XRD; and microstructure were investigated by scanning electron microscopy. Correlated results of DTA, XRD, and SEM analyses indicated initiation of sintering processes at approximately 1300°C and formation of thermally stable minerals (rankinite, gehlenite, anorthite, cristobalite). The investigation highlights a sustainable approach of using fly ash in developing ecofriendly mortars for high‐temperature application.