Title : STRENGTH AND CHLORIDE ION PERMEABILITY OF POND ASH REPLACED SCC - PARTIAL REPLACEMENT TO FINE AGGREGAT
Authors : Bharathi Ganesh,H Sharada Bai and R Nagendra
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Price : 250
Abstract : This paper deals with an experimental study on the assessment of strength and chloride ion permeability of Pond Ash Replaced Self Compacting Concrete - PRSCC mixes replacing - Manufactured sand (M sand) partially by pond ash as fine aggregate in it. Self Compacting Concrete developed in Japan during 1980s [1], is still a topic of research worldwide, so as to popularize the technology with least difficulties. The research work consisted of designing Powder type SCC mixes without VMA by Absolute Volume Method for cementious content of 400kg/m3 and w/b ratio of 0.45. The fine aggregate Manufactured Sand of SCC mixes is replaced with pond ash in replacement levels of 0, 10, 20, 30, 40 and 50% by weight and the mixes are tested for the rheology as per EFNARC 2005. PC based admixture is used to obtain the required rheology. Compressive strength is evaluated at 3, 7, 28 and 56 days to select the optimum replacement range of M sand by pond ash. Further, cylindrical specimens of size of dia. 100mm X 50 mm height are cast for optimum replacement range of 0 - 20% and cured for 28 days. The specimens of Pond ash Replaced SCC (PRSCC) and Normal SCC (NSCC) are tested for their chloride ion penetrability as per ASTM 1202-1997. The results showed that strength of PRSCC mixes up to RL of 20% is comparable with that of NSCC, particularly at 28day curing period, with the maximum reduction amounting only to 10% at RL of 20% for the cementitious content of 400kg/m3. The strength reduction of PRSCC mixes at 50% replacement level is on an average of 24.33% of that of NSCC. The results of RCP test measured in terms of its charge passed in Coulomb fall in the category of low and very low penetrability showing that resistance to chloride ion permeability of PRSCC specimens is better than that of NSCC. This may be due to the presence of finer content of pond ash which improves particle packing resulting in dense SCC, reducing the interconnected pores. This encourages the use of Pond ash in SCC.