Experimental Study On Hardened State Properties Of Self-curing Concrete

Abstract

Concrete is the mostly used construction material in the modern world. However, with the rise of urbanization, heavy use of concrete has started to threaten the humankind due to its disastrous effect on environment. Steel and concrete industries are one of the major CO2 producing industries. Statistics show that an average person uses 1 m3 of concrete in a year making it the most used material and the cement production on global scale may reach 4800 Million Metric tons by 2030 and India being the second largest producer in 2018 with 290 million metric tons. To control this a new environment- friendly structural materials should be utilized instead of ordinary concrete to cope with environmental problems. This has led to the search for alternate sustainable materials to replace Cement. With good success, mineral admixtures have been used to partially replace cement. The technical advantage of using these mineral admixtures is the improvement of many properties in the fresh and hardened phases, including enhanced durability in acidic environments and higher ultimate strength of Concrete. GGBS (Ground granulated blast furnace slag) reaction is both hydraulic and pozzolanic because of the particle shape and increased hydration, GGBS concrete has greater particle packing. Curing of concrete place a major role on strength development and durability of concrete. Improper curing can affect the concrete performance and durability easily. In conventional curing this is achieved by external curing applied after mixing, placing and finishing. Water is maximum utilized commodity and because of this the day- by-day level of the water table is going down. If water has to be purchased for construction works, the cost of construction rises much higher. Also, in case of concreting works done at heights, vertical members, sloped roofs and pavements, continuous curing is very difficult. The performance of self-curing concrete using PEG as self-curing agent with different molecular weights concluded that addition of hydrophilic chemicals in water which is mixed in concrete reduces the evaporation of water. The research identifies Durability properties of the concrete higher for mix C20G1.5P at 7, 14, and 28 days for M20 and M40 grades, However, for the M60 grade, the mix ratio C10G1P demonstrates the highest strength, suggesting the influence of concrete grade in combination with Ground Granulated Blast Furnace Slag (GGBS) and Polyethylene Glycol (PEG 400). Increasing the supplementary cementitious material and self-curing agent strength and durability of concrete increases and up to certain point and then decreases. In addition, the micro structural analyses have been carried out for specimens of optimum level using the Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD).