Repair, Evaluation, Maintenance, and Rehabilitation Research Program. LaboratoryEvaluation of Concrete Mixtures and Techniques for Underwater Repairs

摘要

Concrete mixtures were placed underwater using six placement techniques to (a)examine the cohesive and flow parameters of selected concrete mixtures under different placement situations, (b) estimate those parameters necessary for successful underwater placement, (c) examine the quality of bonding of the repair concrete to the existing concrete, and (d) examine the effect of underwater placement upon the abrasion resistance of the concrete. 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 the concrete. The slump, tremie flow, and air content were also measured. The test method for abrasion-erosion resistance of concrete (underwater method) was used to determine the abrasion-erosion resistance of each concrete. A point-load test for tensile strength was used to determine the bond strength of the repair concrete to the existing concrete.