Behaviour of Ternary Blended Concretes with Different Water Binder Ratios (original) (raw)

Many researchers have studied the properties of ordinary Portland cement concrete by using mineral admixtures like fly ash, micro silica rise husk ash, GGBS as cement replacement materials. A few researchers have done work for triple blended concrete’s using mineral admixtures like micro silica, fly ash. Mineral admixtures are used in order to increase strength and to improve durability of concrete. Blast furnace slag, fly ash and micro silica are some of the mineral admixtures used in varying proportions to achieve such results. The mineral admixtures also affect the properties of concrete in fresh state, rate of strength development and durability in hardened state. Economics and environmental considerations are the key factors in the growth of mineral admixture usage. Micro silica together with super plasticizer is generally used in concrete to enhance strength and durability. Due to its finer size and higher pozolanicity compared to other mineral additives, micro silica incorporation leads to improved mechanical properties of concrete even at early ages. Fly ash, on other hand, as mineral admixture in concrete, enhances its workability, long-term strength and durability. It is generally believed that high strength concretes are achievable only through the addition of micro silica. However, micro silica is relatively expensive compared to cement, especially in countries like India where it is imported. Fly ash on other hand is easily available at lower cost than cement. Moreover, micro silica due to its fine particle size increases the water demand and has tendency to consume higher dosage of superplasticizer, whereas, fly ash due to presence of spherical particles that easily rollover one another reducing inner particle friction ( called ball bearing effect) leads to improved workability and reduction in water demand. Due to associated environmental pollution caused in the production of the cement to reserve the virgin raw material used in cement making for future generations and at the same time due to the availability of supplementary cementations like fly ash, micro silica etc. An attempt has made to study the strength properties of ternary blended concrete for various w/b ratios of 0.55, 0.45 and 0.35 for 28, 90 and 180 days.