Neoprene Pads for Capping Concrete Cylinders

About the report:

The possibility of using neoprene pads as an alternate to sulfur mortar for capping concrete specimens subjected to compression tests was investigated. In preliminary tests to determine the feasibility of the investigation, two batches of concrete were prepared. Subsequently, in the main part of the investigation 8 batches of concrete were made. Concrete cylinders measuring 6 x 12 in. were fabricated at strength levels of about 3,000 psi and 5,000 psi in steel and cardboard molds. For each mold type, specimens were tested for compression using both the neoprene pads and the sulfur mortar caps. The 1/2 in. thick, 6 1/8 in. in diameter neoprene pads had a 50-durometer hardness and were placed in extrusion rings 6 1/2 in. in diameter. In general, the specimens tested with neoprene pads yielded slightly lower compressive strengths than did those tested with sulfur mortar caps. However, at the 95% confidence level the differences were not statistically significant. There also was no significant difference between the results obtained with the specimens prepared in steel molds and those prepared in cardboard molds. The report includes recommendations for further tests.

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