Repair, Evaluation, Maintenance, and Rehabilitation Research Program: Evaluation of Concrete Mixtures for Use in Underwater Repairs

Download or read book Repair, Evaluation, Maintenance, and Rehabilitation Research Program: Evaluation of Concrete Mixtures for Use in Underwater Repairs written by Billy D. Neeley and published by . This book was released on 1988 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concrete mixtures were evaluated to determine which were most suited for placement underwater in thin lifts. The concretes were proportioned to have good workability, good abrasion erosion resistance, and good resistance to washing out of the cement paste. High-range water reducers (HRWR) were used to increase the workability and permit the use of low water cement ratios (W/C) to increase the resistance to abrasion erosion. Low W/C, silica fume, and antiwashout admixtures (AWA) were used to increase the resistance to washout. A washout test was used to determine the relative amount of cement paste lost when the concrete is exposed to a large volume of water. The two-point workability test was used to evaluate the relative workability properties of each mixture. The slump and air content were also measured for most of the mixtures. The test method for abrasion erosion resistance of concrete (underwater method) was used to determine the abrasion erosion resistance of each mixture. The results of these tests were used to determine the combination of materials necessary to produce concrete with the desired properties. Significant correlations that exist between the two-point measurements and washout measurements were examined. The effects that W/C, HRWR's, AWA's, fly ash, and silica fume have upon washout resistance and abrasion-erosion resistance were examined.