Search

The production and utilization of concrete and concrete-based products have drastically increased with the surge of construction activities over the last decade, especially in countries such as China and India. Consequently, this has resulted in a corresponding increase in the energy used for the production of ready-mixed concrete. One approach to reduce the cost of concrete manufacturing is to reduce the energy required for the manufacturing process. The main hypothesis of this study is that the power required for mixing the concrete can be reduced through the use of mineral admixtures in the mix design. Optimization of energy consumption during mixing using admixtures in concrete manufacturing is the predominant focus of this article. To achieve this objective, power consumption data were measured and analyzed throughout the concrete mixing process. The power consumption curve is the only source to distinguish the behavior of the different materials used in the concrete in a closed chamber. In the current research, fly ash and ground granulated blast-furnace slag (GGBS) were used as mineral admixtures to produce ready-mixed concrete. The experimental study focused on the influence of GGBS and fly ash on power consumption during concrete mixing. The results indicated that the use of a higher content of GGBS is more beneficial in comparison to the use of fly ash in the mix due to the lower mixing time required to achieve homogeneity in the mixing process. It was found that the amount of energy required for mixing is directly related to the mixing time for the mix to achieve homogeneity. [ABSTRACT FROM AUTHOR]

The quality of the construction material is required to be improved to enhance the strength and performance of the structure. From the earlier days, admixture assumes a crucial job in cement to improve the basic properties. Before knowing about the admixtures, good knowledge regarding concrete is required. In this work, an endeavor was made to contemplate the conceivable outcomes of utilizing tamarind kernel powder, a naturally available biowaste material which is a hydrocolloid in nature, as an admixture in concrete. The addition of tamarind kernel powder was varied from 0.25 to 1.25% in proportion to the weight of cement used. A huge amount of tamarind seed wastes are produced every year especially in India it is nearly 97,000 metric tons per year. In the absence of waste disposal, the utilization of tamarind seed for concrete improvement will be a great development. In this research article, tamarind kernel powder was added to fresh concrete and relevant tests were conducted on fresh and hardened concrete before and after the addition of tamarind kernel powder. Further, nondestructive tests were also carried out on concrete added with tamarind kernel powder. The concrete shows good enhancement in strength until the addition of 1% of tamarind kernel powder to the weight of cement. Moreover, the workability, mobility and compaction factor results obtained in this experiment show that the optimal addition of tamarind kernel powder does not affect the properties of fresh concrete. The tests on hardened concrete and results obtained from nondestructive testing methods confirm the same. Hence, this experimental work shows that the natural hydrocolloid, that is, tamarind kernel powder can be added to an amount of 1% to the weight of cement which shall not affect the other parameters of concrete but increases the strength considerably. [ABSTRACT FROM AUTHOR]

In this experimental investigation, a brief review is presented on high strength concrete by using mineral and chemical admixtures. We have designed high strength concrete of grade M80. We have used all the mineral admixtures, namely, fly ash, blast furnace slag, silica fume and metakaolin, contributed by various reputed industries in India. We have collected all the details of these mineral admixtures from those reputed industries, and a brief introduction of all mineral admixtures is presented in this project work. We have also used superplasticizer (chemical admixture), namely, conflo manufactured by "fosrock chemicals" in Bangalore. We have used this superplasticizer in order to achieve good workability under lower water-cement ratio for high strength concrete such as M80. We have compared the compressive strengths of all these mineral admixtures at their individual replacements and combinations of various percentages. We have also found out the percentage replacements of these mineral admixtures in order to achieve maximum strength. We have presented the results in the form of graphs. [ABSTRACT FROM AUTHOR]

Managing sludge generated by treating groundwater contaminated with geogenic contaminants (fluoride, arsenic, and iron) is a major issue in developing nations. Their re-use in civil engineering applications is a possible pathway for reducing the impact on the geo-environment. This paper examines the re-use of one such sludge material, namely, fluoride contaminated bone char sludge, as partial replacement for fine aggregate (river-sand) in the manufacture of dense concrete specimens. Bone char sludge is being produced by defluoridation of contaminated groundwater in Nalagonda District, Andhra Pradesh, India. The impact of admixing 1.5¿9% sludge contents on the compression strength and fluoride leaching potential of the sludge admixed concrete (SAC) specimens are examined. The compression strengths of the SAC specimens are examined with respect to strength criteria for manufacture of dense, load-bearing concrete blocks. The fluoride release potential of the SAC specimens is examined with respect to standards specific to disposal of treated leachate into inland surface water. [Copyright &y& Elsevier]