Effect of Pumping on Properties of Concrete. Final Report

摘要

This study investigates the changes that occur in concrete due to the effect ofpumping. This is an important study since the pumping of fresh concrete is gaining popularity due to economics and ease of construction. The detrimental and beneficial effects of pumping if any should be known so that they may be accounted for in design. Samples were collected from eleven field sites before and after pumping. Collection and testing of concrete was performed in accordance with the ASTM specifications. By testing samples from before and after pumping determinations were made about any changes to concrete properties caused by pumping. The tests used in this study were Air Content (ASTM C173), Slump (ASTM C143), Unit Weight (ASTM C138), Compressive Strength (ASTM C39), Rapid Chloride Permeability (ASTM C1202), Water Permeability (FDOT), and Microscopic Air Void Content (ASTM C457). The test results were statistically analyzed to determine whether the changes caused by pumping were statistically significant. The air content of the fresh concrete showed a general decrease of about one percent. The other tests, with the exception of slump, also showed that changes had occurred due to pumping. This is as expected because the tests are closely related to the concrete's air content.