Industrial and Environmental Application of High Volume Fly Ash in Concrete Production

摘要

A large number of structural properties of plain concrete are improved with addition of admixtures to concrete. It is well known that the addition of fly ash to plain concrete improves workability, strength, durability, less permeable and more stable. In conventional concrete the flexural strength reaches a maximum value between 14 and 28 days. In high volume fly ash (HVFA) concrete the strength keeps on increasing with age because of pozzolanic reaction of fly ash and strengthening of the interfacial bond between cement paste and aggregate. The use of fly ash as a partial replacement for Portland cement will usually reduce water demand and bleeding of HVFA concrete ranges from negligible to very low. Only few research works have been carried out earlier on flexural study on R C conventional beams without fly ash. Therefore in this investigation an attempt has been made to study any likely improvement on the effect of fly ash on the properties of HVFA concrete in R C beam elements with confinement of stirrups in compression zone. It has been suggested that the effective use of fly ash minimizes the disposal of fly ash, which also solves an environmental problem. This HVFA concrete is easy to pump, consolidate and finish the surface, free from cracks, reduces carbon-dioxide emissions, superior environmental friendliness, reduction in stone mining since it consumes less volume of Portland cement. The methodology adopted above improves ductility and improves the rotation capacity of the joints of framed structure, thus, improving the ultimate load carrying capacity. An attempt is also made to compare the load versus deflection of the HVFA concrete beams with conventional RCC beams and evaluated the performances of the proposed method of confinement. The results indicated that the confinement in the form of stirrups improves the ultimate strength and ductile behaviour of the concrete (IS 3812-1981). An attempt has been made in the present paper to highlight the utilization of fly ash in construction.