Abstract The project aims in the utilization of fly ash in concrete with addition of mineral admixture, aiming for the improvement of the different characteristics of concrete and in order to increase the concrete performances and to maximize the economic and environmental benefits. The main objectives of this paper is to utilize fly ash concrete with mineral admixture, investigating the possibility of increasing the performance of concrete and improve the cohesiveness and workability of the concrete, resulting in the reduction of thermal cracking and maximizing the environmental and economical benefits.
In this study different tests will be carried out such as, slump test, compression test and carbonation test to test the character of the concrete mixed with fly ash and admixture. introduction The Project is about an Experimental study on the utilization of fly ash in concrete with mineral admixture, aiming for the improvement of different types of concrete and to increase the concrete performances and to maximize the economic and environmental benefits. History of fly ash The use of Fly Ash in concrete was first carried out by Davis and his associates in University of California in 19374.
Though extensive research was carried out throughout the world to encourage the use of Fly Ash in construction industry, only a few milestones could be accomplished till 1960 and that too in industrialized countries only. As far as Oman is concerned, the first ever study on use of fly ash in concrete was carried out in 1955 by CBRI, Roorkee5, in the form of a review of American and Australian research work on Fly ash. Later, Fly ash was used in small proportions in mass concreting for dams and other hydraulic structures. Methodology The methodology used in this project is an experimental based study where the tests carried out are:
Slump Test: for the means of checking that the correct amount of water has been added to the mix which basically means the workability of the concrete to measure how easy the concrete is to place, handle and compact. The measured slump must be within a set range, or tolerance, from the target slump. Slump Test Tools: Standard slump cone, Small scoop. Bullet-nosed rod. Rule Slump plate. Compression test: Shows the compressive strength of hardened concrete. The testing is done in a laboratory off-site. The only work done on-site is to make a concrete cube for the compression test.
The strength is measured in Megapascals (MPa) and is commonly specified as a characteristic strength of concrete measured at 28 days after mixing. The compressive strength is a measure of the concrete’s ability to resist loads, which tend to crush it. Compression Test Tools: Cube mold. Small scoop Bullet-nosed rod , Steel float Steel plate. Carbonation test: happens when carbonating acids made by the atmospheric carbon dioxide in water reacts with hydration products, which will leads to the deterioration of the reinforcement in the concrete, the carbonation test was carried out in this project to measure the diffusivity of the concrete.
The carbonation depth is measured by the application of Phenolphthalein to the surface. Conclusion This research investigated the effect of mineral admixtures (fly ash) on concrete because it is one of the most valuable industrial wastes which contains a non-crystalline silicon dioxide with high specific surface area and high pozzolanic reactivity, it is found that proportions of fly ash in concrete can vary from 31% – 81% for various grades of concrete.
The aim of this project was met where the mix with utilized fly ash and with the addition of mineral admixtures has passed in the compressive strength test and has shown low carbonation rates, in addition as expected it was confirmed that Fly ash in concrete reduces the compressive strength at early stages but there is an extreme increase in the compressive strength at later stages, which is beneficial in the construction industry.
Furthermore all the results of both mixes where considerably close which also proved again that concrete having fly ash can be used on an industrial base here in the Sultanate of Oman which will aid in the improvement of the different characteristics of concrete, In order to increase the concrete performances and to maximize the economic and environmental benefits.