The Effect Of Aggregate Size On Strength Of Portland Cement Concrete

Author : Thomas Francis McDonnell
Publisher :
ISBN 13 :
Total Pages : 95 pages
Book Rating : 4.:/5 (895 download)

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Download or read book Effect of Mineral Admixtures and Coarse Aggregate Size on Compressive Strength and Freeze-thaw Resistance of Portland Cement Concrete written by Thomas Francis McDonnell and published by . This book was released on 2007 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Ohio Department of Transportation (ODOT) has developed a series of portland cement concrete mix designs for use on all infrastructure projects throughout the state. The standard forms of these mix designs differ in terms of the compressive strength they are expected to achieve after a curing period of 28 days. Because of the state's climate, one requirement common to every mix design used by ODOT, however, is high resistance to damage from cycles of freezing and thawing. Options currently permitted by ODOT for varying these mix designs include the use of different coarse aggregate sizes and substitution of a portion of the portland cement with additional fine aggregate or one of three mineral admixtures. These admixtures include fly ash, ground granulated blast furnace slag (GGBFS) and micro silica. All of these admixtures are produced from materials that are recycled from processes unrelated to concrete production. These processes include coal fired steam generation, pig iron production and silicon manufacturing.The objective of the research presented in this thesis was to evaluate the effect that mineral admixtures and coarse aggregate on ODOT Class C (4,000 psi) concrete in terms of compressive strength and freeze-thaw resistance. These evaluations were performed through laboratory testing of specimens cast from individual mixes. Information is provided on the materials used to create a concrete mix, as well as a brief summary of the development of mix design methodologies. Detailed descriptions of the freeze-thaw resistance and compressive strength testing are also included, with a discussion of the associated mechanisms of failure. Conclusions are offered based on trends observed from analysis of the test data. In general, the results of the testing indicate that freeze-thaw resistance is not detrimentally influenced by the addition of mineral admixtures or the size of the coarse aggregate used. Each of the mineral admixtures does affect the resulting concrete mix in slightly different ways, and one may be more desirable than another based on required performance. In addition, all of the mix designs studied attained average compressive strengths in excess of the target value of 4,000 psi.