Development of high performance concrete composites using Class F fly ash and PCC bottom ash, and a statistical model to predict compressive strength of similar concrete composites.

摘要

It is a common knowledge that the use of concrete is as old as the evolution of human civilization. People have always dreamed beyond the dotted lines and so does the usage of concrete. With the rapid industrialization and globalization, the journey from ordinary concrete to high performance concrete (HPC) has been swift and remarkable. The diversification and utilization of high performance concrete has given the tool in the hands of engineers and architects who can now design and execute buildings of any shape and size deemed impractical a few decades ago.;The aim of this research was to develop high performance concrete composites having different percentages of Illinois Class "F" fly ash and bottom ash by replacing the appropriate proportions of Type 1 portland cement and fine aggregate, respectively. The target was to develop high performance concrete composites that have compressive strength of 8,000 psi (55 Mpa) after 28 days of curing in water with a slump of 4+/-½" (102mm +/- 13mm) and air content between 4 and 6 percent. In order to achieve the targeted air content, an air entraining agent DARAVAIR 1400 was used. The water-cement ratio of 0.3 was maintained throughout the research and to achieve the targeted slump, high-range water reducer ADVA 140M was used.;The engineering parameters of the high performance concrete composites and an equivalent control mix were evaluated by conducting a detailed laboratory study which included several tests, e.g., slump, fresh air content, compressive strength, splitting-tensile strength, flexural strength, resistance to rapid freezing and thawing, sealed shrinkage and free swelling, and rapid chloride permeability.;The results presented show that all high performance concrete composites developed in this study achieved the targeted compressive strength of 8,000 psi (55 MPa) after 28 days of curing in water. The results of the durability tests show that the concrete composites developed in this study have trends similar to that of an equivalent conventional concrete. Based, on the results of this study, it was concluded that the concrete composites have potential to be used on real world projects and thus help the environment by substantially reducing the amount of fly ash and bottom ash going to ash ponds or landfills.;Based on the experimental test result data, a detailed statistical analysis was conducted to develop an empirical model to predict compressive strength of similar concrete composites for a given amount of fly ash, bottom ash, and curing period. Additional laboratory tests were performed to validate the mathematical model.