The objective of this study is to improve the freezing and thawing resistance of NonAE concrete. It is believed that freezing of macroscopic water in meso capillary pore of hydrated cement causes the frost damage due to freezing and thawing. In this study, it was confirmed that applying a hydrophobic compound into the concrete to block the continuity of meso capillary pore decreases the freezing water by suppressing ice crystal penetration. Further, the effective particle size of the hydrophobic compound was 10-110 μm. Thus, freezing of water in capillary pores in the range of 10 to 110 μm is the main cause for the deterioration due to freezing and thawing. It is anticipated that this technology, without entrained air, can be applied to produce concrete for better performance in freezing and thawing environment.

In this study, two rheology tests were conducted to obtain the rheological constants of mortar. The first was sphere pull-up test, the second was the measurement by using rotational vane viscometer. The rheological constants were obtained by approximating flow curve of each test by Bingham model. Using them, the mini slump test was analytically reproduced by Moving Particle Semi-implicit (MPS) method.The analysis results using the rheological constants of sphere pull-up test agreed with the flow spread and slump shape. Therefore, the rheological constants obtained by the experiment are effective for the MPS analysis.

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In this study, the authors investigate various properties of coal gasification slag fine aggregate (CGS) when applied to high-strength concrete. The amount of admixture using CGS concrete is lower than that of ordinary aggregate concrete. The initial compressive strength and the onset of strength up to 91-day of age were smaller than those using ordinary aggregate. Young's modulus of CGS concrete is approximately 1.1 times of ordinary aggregate concrete. CGS concrete reduced autogenous shrinkage only in the case of ordinary portland cement. In the case of moderate heat portland cement, the autogenous shrinkage of CGS concrete is the same as land sand concrete.