부산대학교 도서관

A testing program has been initiated to measure and compare the performance in concrete of two hydraulic cements. Both meet the prescriptive specification for portland cement; one cement is a mixture of 98% portland cement and 2% slag, and the other is a similar portland cement with no slag. The program compares their performance in a broad range of standard mortar and concrete tests. Mixes include both chemical admixtures (an air-entraining agent and a water reducer) and mineral admixtures (ground, granulated blast furnace slag, and Class F and Class C fly ashes). The preliminary results show only minor differences in performance between the two cements. An important conclusion of this presentation is that a standard protocol is needed for measuring performance of cement in concrete. The testing program we used is quite broad and includes several tests that are not part of the performance specification for hydraulic cement. Many of the standard tests for hydraulic cement provide quality tests for use in cement production, but do not assure that the cement will perform properly in concrete. A standard protocol would include a range of tests that assure performance of cement in concrete, would include other concrete materials (aggregates, chemical admixtures, and mineral admixtures), and would reduce the number of tests required to assure performance of a new cementitious material.