PURPOSES : This paper presents the experimental results of tests conducted on concrete produced with air-cooled (AS) and water-cooled (WS) ground blast-furnace slag exposed to multi-deterioration environments of carbonation and scaling. METHODS : Carbonated and uncarbonated concrete specimens were regularly monitored according to the ASTM C 672 standard to evaluate the durability of concrete exposed to both scaling and combined carbonation and scaling conditions. Additionally, mechanical properties, such as compressive strength, flexural strength, and surface electric resistivity, were analyzed. RESULTS : It was found that concrete specimens produced with AS and WS had a beneficial effect on the mechanical properties because of the latent hydraulic properties of the AS and WS mineral admixtures. Moreover, carbonated concrete showed good scaling resistance in comparison to uncarbonated concrete, particularly for concrete produced with AS and WS. CONCLUSIONS : The improved scaling resistance of carbonated concrete showed that AS is a suitable option for binders used in cement concrete pavements subjected to combined carbonation and scaling.

The blast load is classified into free-air blast and surface blast following the location of explosion and surface. In this paper, several equations for blast load calculation are explained briefly and a modified equation for free-air blast load is suggested. The modified equation is based on Kingery-Bulmash equation which is used in UFC 3-340-02 and Conwep model. In this modified equation, the process of calculation is simplified against the original equation, and the number of coefficients is reduced under 5. As a result, each parameter of estimated data by modified equation has less than 1% of error range comparing with Kingery-Bulmash equation.

본 연구는 최적의 냉해동 조건을 확립하고 설정된 조건에 따라 냉해동이 당근에 미치는 이화학적 분석 및 영양성분의 분석을 진행하였다. 본 실험에서는 강제송풍방식을이용하였으며, 자연대류식(0.2oC/min), 저속(0.4oC/min) 및고속(1.6oC/min)으로 냉동속도를 조절하여 -12oC까지 냉동하였다. 해동조건은 전자레인지를 이용하여 0, 200, 400,800W의 세기로 출력을 조절하여 시료의 중심부 온도가4oC가 될 때까지 해동하여 분석에 사용하였다. 당근의 강도는 냉해동 후 유의적으로 감소하는 경향을 보였으며, 특히 200, 400W 해동 시 냉동 속도가 빠를수록 감소하였다.해동감량의 경우 해동방법에 따른 유의적인 차이는 없었지만 냉동속도가 높을수록 감소하는 경향을 보였다. pH 및색도의 데치기 후 당근과 처리구간의 유의적인 차이는 보이지 않았다. 그러나 전자 현미경 관찰 결과, 냉동속도가빨라질수록 기공의 크기가 작아지는 것을 확인할 수 있었으며 이는 빠른 냉동속도가 식품 조직의 손상을 막는데 영향을 미친다는 것으로 보인다. 비타민 C 및 유기산(oxalicacid, malic acid 및 fumaric acid) 함량의 경우 유의적인차이는 나타나지 않았다. 유리당 함량의 경우에는 sucrose함량은 자연대류 냉동 시 가장 높았고, fructose 및 glucose의 함량은 유의적인 차이가 없었다. 본 연구 결과 냉해동방법에 따른 영양학적 변화는 대부분 데치기 후 당근과 유사하였으나, 당근을 고속으로 냉동할 시 물리적 변화 및조직 손상을 최소화 하였으므로 당근의 품질을 유지하는데효과적인 것으로 판단된다.

Method for Protect of the river levee was method for installing concrete revetment block and concrete mat method in Korea. But this method is non-environmental approach because the vegetation can not take at all. To solve these problem, the method has been applied using porous vegetation concretes. Porous vegetation concrete has filler technique to provide water retention and nutrient a into the porous interior in order to facilitate plant growth. But filler used increasing the cost and the construction period. Therefore in order to not use a filler, a high absorption rate and good absorption capacity needed aggregate. Current, Blast furnace slag aggregate has been used in architectural and civil engineering field as an alternative aggregate resources. Blast furnace slag aggregate is high absorption rate and lighter in weight per unit. This study evaluated the absorption capacity of the blast furnace slag aggregate. Phosphorus Sorption experiment was carried out to produce a cylindrical acrylic(diameter 11cm, height 90cm). There filling the aggregate, for supplying the test solution was using as a pump from bottom to top. And The water of having passed through the solution was analyzed. Results, blast furnace slag aggregate showed absorption capacity of 64~77% of PO43-P and T-P. Crushed aggregate show absorption capacity of 6~24% of PO43-P and T-P. Blast furnace slag aggregate showed excellent result of good absorption capacity compared to the crushed aggregate showed excellent result.

In this study, from the material properties of the aggregates into the actual applications were evaluated for utilizingthe air-cooled blast furnace slag as the coarse aggregates (SG) in PHC piles. The physical and chemical characters ofthe SG were satisfied the standards presented in KS F 2544 for concrete blast furnace slag aggregates. And it was satisfiedthe environmental-factor-evaluation, including the soluble, heavy metal elution and total mercury content, and etc. In casethe non-washed type SG is used, the S/A ratio adjustment according to micro-powder of the aggregate surface and chemicaladmixture adjustment are needed in order to satisfy the aimed material properties. As the replacement ratio of SGincreased, the manifestation rate of compressive strength of the PHC piles was decreased. Particularly, in case non-washingtype SG, the manifestation rate more decreased. Therefore, the elimination of the pop-out materials and cleaning processare necessary for the production process for using the SG as coarse aggregates of PHC Piles