Relating Materials Quality to Materials Performance to Structural Performance of Concrete.

摘要

Portland cement,aggregates for portland-cement concrete,admixtures for concrete,and curing materials for concrete are usually procured for use in construction under specifications that stipulate levels of quality as indicated by the results of standardized tests of samples. The information obtained from these tests is believed to be related directly or indirectly to levels of performance of the material itself,the composite of which it is a constituent,the structural element of which it is a component,and the structural system of which it is an element. The testing is limited to determinations that can be completed in the time available for testing and at an appropriate cost. The levels of quality are selected to be few for simplicity and are frequently higher than needed to insure adequacy of performance in the specific situation;rarely lower. Attention has primarily been directed to those few cases where less than adequate performance has resulted. Greater economies and more prudent utilization of natural resources will result if attention were directed to those much more numerous cases where stipulated levels of quality are higher than needed. (Author)