Dowel Bar Retrofit

Author : Jan Olek
Publisher : Purdue University Press
ISBN 13 : 9781622602124
Total Pages : 288 pages
Book Rating : 4.6/5 (21 download)

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Download or read book Dowel Bar Retrofit Mix Design and Specification written by Jan Olek and published by Purdue University Press. This book was released on 2012-08-01 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: When dealing with the issue of repair of concrete pavement repair using dowel bar retrofit technique, it is very desirable for the repair material to have high fluidity that can ensure good compaction and facilitate flow to tight spaces, preferably without the use of a vibrator. The focus of this project was on identifying critical properties that control long-term performance of repair concrete, especially rapid-setting materials extended using pea gravel (maximum size aggregate 9.5 mm). In the first phase of this project, four commercial rapid-setting materials (CRSMs) were selected and development of mixture proportions in terms of optimum pea gravel content and water content was performed. Optimized mixtures were further evaluated at three different initial temperature conditions. The properties evaluated included workability, setting time, rate of compressive strength developed, slant shear bond strength, freeze-thaw resistance, air-void system characteristics of hardened concrete, drying shrinkage and cracking potential. It was observed that some of the CRSMs evaluated did not meet requirements of ASTM C 928. All, except one, CRSMs tested exhibited low resistance to freezing and thawing but all had high resistance to cracking. In the second phase of the project, rapid-setting self-consolidating concrete (RSSCC) was developed using ternary blend of cementitious materials, high-range water reducer (HRWR) and accelerators. Slump flow, visual stability index (VSI), compressive strength at various ages and the power consumption values for the mortar mixer indicated that a five minutes mixing sequence involving a 2-step addition of HRWR produces stable RSSCC mixture. The results of various tests carried out indicate that it is possible to develop a small aggregate size-based self-consolidating repair concrete that achieves a compressive strength of 19 MPa at the end of 6 hrs, has good bond characteristics and has excellent freezing and thawing durability (DF>90%).