Tennessee Flowable Fill Study.

摘要

Twenty-three different excavatable flowable fill (EFF) mixtures were placed in trenches simulating utility cuts during March through May of 2001. All EFF mixtures were tested for flow, unit, weight, gravimetric air content, suitability for load application, and compressive strength development over time. The trenches were excavated in March 2003. Nine EFF mixtures were used to access the impact of Portland cement content and ASTM C 618 Class F fly ash content. Portland cement contents of 30, 45, and 60 lbs/CY and ASTM C 618 Class F fly ash contents of 300, 370, and 440 lbs/CY were used to evaluate the impact of component proportions. PC-F Ash EFF mixtures with cementitious materials contents between 415 and 500 lbs/CY were found to have a high probability of having an ASTM D 6103 flow greater than 8-inches and passing the ASTM D 6024 ball drop test in less than 24 hours. In addition, the PC content of PC-Class F fly ash EFF mixtures appears to be more important to early compressive strength development. Further, strong relationships exist between component material proportions and 28-day and maximum compressive strengths and excavation difficulty. Six EFF mixtures were used to access the impact of Portland cement content and high-unburned carbon fly ash content. Portland cement contents of 45 and 60 lbs/cy and high-unburned carbon fly ash contents of 370, 440 510 lbs/CY were used to evaluate the impact of component proportions. The use of high carbon ash typically extended the time required to pass the ball drop test and often generated some erratic strength results. Therefore, the research team was hesitant to recommend the use of mixtures containing high carbon ash without further research.