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Effective In-situ Strength of High Strength Concrete Columns

出版	CSIRO. Division of Building, Construction and Engineering, 1993
URL	http://books.google.com.hk/books?id=NjvyZwEACAAJ&hl=&source=gbs_api

註釋An investigation was undertaken to examine the effects of in-situ conditions on the strength of high strength concrete columns. The variables investigated were column size, surface curing regime, mix proportions and the use of silica fume. It was found that in-situ strengths were not uniformly distributed across a cross-section. In general the highest strengths were found at the centre of a cross-section. These strength gradients effectively lowered the uni-axial load-bearing strength of an in-situ column and could have even more serious implications for eccentric loading. Effective column strengths were calculated to provide an average axial load bearing strength of a cross-section. For the high strength concretes investigated, the ratios of effective to cylinder strengths were generally lower than the 0.85 factor commonly used in column design. The in-situ concrete strength in 40'0 x 400 mm columns were also significantly higher than those in 800 x 800 mm columns.