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原文传递 Interlaboratory Evaluation of Variability in the ASTM C 457 Linear Traverse Method. Final rept.

题名：	Interlaboratory Evaluation of Variability in the ASTM C 457 Linear Traverse Method. Final rept.
作者：	SIMON, M. J.
关键词：	Concretes-; Air-entrainment; *Evaluation-.;Frost-; Voids-; Concrete-pavements; Missouri-; Microscopy-; Parameters-; Compressive-strength; Linear-traverse; Round-robin; Comparison-; Precision-; Variability-; Air-content; Spacing-; Mechanical-properties.
摘要：	The vital role of air entrainment in preventing freeze-thaw damage in concrete is well known and well documented (Powers 1949). Through the action of an air entraining agent (AEA) added to fresh concrete, an air void system comprised of various microscopic voids is established. There are several parameters of the air void system, which are considered important indicators of freeze-thaw resistance. Measuring these parameters and their adequacy provides extremely useful information on concrete freeze-thaw resistance. ASTM C 457 describes two methods for assessing the adequacy of the air void system in hardened concrete: the linear traverse and modified point count (ASTM 2004). Both procedures in ASTM C 457 require a human operator to use a microscope, or a video monitor and camera attached to a microscope, to make the necessary observations and measurements. The process has been long recognized as tedious and time-consuming, requiring a skilled and experienced operator to ensure reliable, consistent results.
报告类型：	科技报告