• Journal of the Korea Concrete Institute
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• v.16 no.1 s.79
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• pp.102-110
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• 2004

Recently, production cost of ready mixed concrete(remicon) has been increased due to the rising cost of raw materials such as cement and aggregate etc. cause by the upturn of oil price and increase of shipping charge. The delivery cost of remicon companies, however, has been decreased owing to their excessive competition in sale. Consequently, remicon companies began to manufacture the concrete by mixing ground granulated blast furnace slag(GGBF) in order to lower the production cost. Therefore, the objective of this study was to predict 28-day strength of GGBF slag concrete by early strength(1 day-strength, 7 day-strength) for the sake of managing with ease the quality of remicon. In experimental results, the prediction equation for 28 day-strength of GGBF slag concrete could be produced through the linear regression analysis of early strength and 28 day-strength. In order to acquire the reliability, all mixture were repeated as 3 times and each mixture order was carried out by random sampling. The prediction equation for 28 day-strength of GGBF slag concrete by 1-day strength(hot-water method) won the good reliability.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.4
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• pp.61-71
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• 1987

Accelerated strength testing is a available method for quality control of concrete. This paper presents the improved hot water ($70^{\circ}C$) methods and discusses how these methods can be adapted for predicting 28 day strength. The strength results have been analyzed by statistical techniques and correlation between early and 28 day strength are showed by prediction line. The test results show that the methods proposed in this paper are usable to predict the potential quality of concrete with low variation and good relationship between two strengths.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.91-98
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• 2009

Recently, production cost of ready mixed concrete has been increased due to the rising cost of raw materials such as cement and aggregate etc. cause by the upturn of oil price and increase of shipping charge. The delivery cost of ready mixed concrete companies, however, has been decreased owing to their excessive competition in sale. Consequently, ready mixed concrete companies began to manufacture the concrete by mixing ground granulated blast furnace slag(GGBF) and fly-ash in order to lower the production cost. Therefore, the objective of this study was to predict 28 days strength of GGBF slag concrete by early strength(warm and hot water curing method) for the sake of managing with ease the quality of ready mixed concrete. In experimental results, the prediction equation for 28 days compressive strength of GGBF slag concrete could be produced through the linear regression analysis of early strength and 28 days strength. In order to acquire the reliability, all mixture were repeated as 3 times and each mixture order was carried out by random sampling. The prediction equation for 28 days strength of GGBF slag concrete by 1 day compressive strength(accelerated testing) according to warm and hot water curing method won the good reliability.