Mechanical Properties of Concrete Made with High Volume Fly Ash Blended Concrete

摘要

Portland cement concrete is a major construction material worldwide. Unfortunately the production of Portland cement releases large amount of CO_2 into atmosphere and because this gas is a major contributor to the green house effect and global warming of, the planned and developed countries are considering very severe regulations and limitation on the CO_2 emissions. It is now widely accepted that reduced production of Portland cement (PC) and increasing partial replacement of PC with pozzolanic and cementitious byproducts, fly ash, ground granulated blast furnace slag (GGBS), or rice husk ash, resulting, in the conservation of mineral wealth such as limestone, lower energy consumption and lower green house gas emissions and controlled global warming and climate change in the manufacture of PC, enhancement of service life of cement concrete structures by improving concrete durability, reduced cost of cement, and highly beneficial elimination of environment threatening gigantic fly ash deposits, is the essential element of the foundation, upon which the edifice of sustainable development of the concrete construction industry can be built. High volume fly ash (HVFA) cement and concrete directly serve this highly useful beneficial cause. This paper presents the result of a study on the mechanical properties of concrete made with HVFA cement and concrete. Mechanical properties were tested with fly ash replacement increasing from 10 to 60 percent in the blended cement in increments of 10 percent. Result showed 50% is the optimum replacement. The use of HVFA cement resulted in lower compressive and flexural strengths at early ages(before 28 days) compared with control concrete and mechanical properties increased after 28 days and the difference in strength between controlled concrete and HVFA concrete narrowed down at 90 days. The test results obtained were compared with those of control concrete.