This investigation was performed to develop technology for manufacturing cast-concrete products using Class F fly ash, coal-combustion bottom ash, and used foundry sand. A total of 18 mixture proportions with and without the by-products was developed for manufacture of bricks, blocks, and paving stones. Replacement rates, by mass, for sand with either bottom ash or used foundry sand were 25 and 35%. Replacement rates, by mass, for portland cement with fly ash were 25 and 35% for bricks and blocks, and 15 and 25% for paving stones. Analysis of test data revealed that bricks with up to 25% replacement of cement and blocks with up to 25% replacement of cement and sand with recycled materials are suitable for use in both cold and warm climates. Other bricks and blocks were appropriate for building interior walls in cold regions and both interior and exterior walls in warm regions. Paving stones with 15% replacement of cement with fly ash showed higher strength, freezing and thawing resistance, and abrasion resistance than the control specimens.
This project was conducted to evaluate the performance and leaching of controlled low strength materials (CLSM) incorporating fly ash and foundry sand. Two different CLSM (or flowable slurry) reference mixtures (equivalent to available production CLSM mixtures) were proportioned for unconfined compressive strength levels in the range of 0.3-0.7 MPa (50-100 psi), at 28 days, using two sources of ASTM Class F fly ash. For each reference mixture, other mixtures were proportioned using two sources of foundry sand (molten metal-casting mold sand) as a replacement for fly ash in the range of 30-85%. The ingredients of the slurry mixtures-fly ash, clean foundry sand, and used foundry sand-were tested for their physical and chemical properties and their leachate characteristics. Portland cement used as the primary binder was also tested for its properties. All CLSM mixtures made with and without foundry sand were evaluated for settlement, setting and hardening characteristics, compressive strength, permeability, and leachate characteristics. The leachate results of these CLSM-making materials were below the enforcement standards (ES) of the Wisconsin Department of Natural Resources (WDNR) groundwater quality standards (GWQS). They also met practically all the parameters of the drinking water standards. A number of CLSM mixtures incorporating fly ash and foundry sand are recommended for construction applications.
This investigation was performed to establish the effects of the source and amount of fly ash on abrasion resistance of concrete. A reference concrete was proportioned to have a 28-day age strength of 41 MPa. Three sources of Class C fly ash were used in this research. From each source, three levels of fly ash to total cementitious materials content ͑40, 50, and 60%͒ were used in producing the concrete mixtures. The water to cementitious materials ratio was kept constant at 0.30 for all mixtures. An accelerated abrasion testing method, a modified ASTM C 944 test, was used to measure the abrasion resistance of this high-strength concrete. The effects of both the source and the amount of fly ash on abrasion resistance of concrete were noticeable. All concrete mixtures with and without fly ash exhibited high abrasion resistance in accordance with the ASTM requirement. Concrete abrasion resistance was not greatly influenced by inclusion of Class C fly ash up to 40% of total cementitious materials. However, a slight decrease in abrasion resistance of high-volume fly ash ͑HVFA͒ concrete ͑especially at fly ash content above 50%͒ was noted as compared to the reference mixture without fly ash.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.