In previous research team had reported that the durability of carbonation is improved by filling voids due to the saponification reaction of oil and concrete. The purpose of this study was to have experimental investigation the effect of mock-up experiment on the carbonation resistance of the waste concrete admixture.

From the previous research, as a solution of carbonation of high-volume SCM concrete, outstanding performance of emulsified refined cooking oil with applying on the surface of the concrete was suggested. As a comparative study, the aim of this research is evaluating carbonation resistance and pore structure of high-volume SCM concrete depending on the painting substances of emulsified refined cooking oil and modified silicate base permeating paint, which is commercial product by mock-up test.

As the usage of supplementary additives such as blast furnace slag and fly ash for concrete was increased, the carbonation of concrete has been a problem. Hence, in this research, as a solution of carbonation of the high-volume supplementary additive concrete, the effect of waste oil based liniment on carbonation and chloride resistivity was analyzed when it applied on the surface of the concrete.

This research provides the analyzing case of abnormal expanding of concrete including steel slag aggregate as a recycled aggregate. To determine the reason of abnormal expansion, the components of concrete were searched and the aggregate was found out as a reason of this expansion. The aggregate used was a type of steel slag aggregate without any specific treatment for volumetric stability such as fast-cooling or aging. SEM observation of the aggregate and XRD analysis of the cement paste were conducted and it was found out that the surface of the aggregate is very rough and the cement paste contained a lot of calcium and magnesium. From this research, it is considered to contribute on providing the actual case of failure using steel slag aggregate for concrete.

The objective of this paper is to investigate the effect of spreading time of waste cooking oil (WCO) on durability of high volume blast furnace slag concrete. Carbonation and resistance to chloride attack were measured according to spreading time of WCO. WCO was spreaded on the surface of the concrete with different curing condition after demolding. Blast furnace slag with 60% was incorporated into concrete with 45% of W/B. Test results indicated that carbonation and penetration resistance of chloride attack had favorable results with the condition of 28days water curing and spreading WCO.

In this study, natural fine aggregates(NFA) and recycled fine aggregates(RFA) was applying in the lightweight foamed concrete. To replacement of OPC, high volume blast furnace slag was used and incineration ash and recycled aggregates powder were used as alrali activator, Fundamental performances of lightweight famed concrete has been tested. Results showed that as the increase of foam conduction ratio, the strength and the density has been decreased

Comparing with using ordinary Portland cement, using blast furnace slag as binder in concrete shows low resistance for carbonation phenomenon. In this research, we focus on carbonation of high volume blast furnace-blended concrete, analysis the reason and find a more efficient method which comparing with using ordinary Portland cement, using FC shows better effort on concrete carbonate resistant.

While carrying out a series of study for improving the durability of High Volume Admixture Concrete using the ERCO, we found that the resistance of freezing and thawing declined due to the decrease of air amount in concrete when using the ERCO. In order to solve the problem, we carried out an experiment using the DEM. As a result of that, it did not affect the basic characteristic of concrete, and the problem of decreasing air amount caused by using the ERCO is also considered to be solved by securing the target air amount.

This paper is to investigate experimentally the effect of waste cooking oil on compressive strength and chloride penetration resistance of high volume fly ash and blast furnace slag concrete. According to results, the incorporation of waste cooking oil resulted in an improvement of penetration resistance of chloride.

This study investigates the effect of emulsified refined cooking oil (ERCO) on the fundamental properties of cement paste, and their results are compared with that of shrinkage reducing admixture (SR). Results showed that ERCO decreased early strength, but retained the strength at the later age of 28 days, slightly higher than pure OPC

This study investigates the effect of surface coating materials on the level of resistance of concrete carbonation. For the surface coating materials, paint (Pa), waste cooking oil (WCO) and waste cooking oil + paint (WCO + Pa) were prepared and applied on the surface of concrete specimens after exposure to accelerated carbonation environment for four weeks.

In previous research, it was found that waste oil was effective on resisting carbonation of concrete. This study is to find the effect of waste oil on the fundamental properties of concrete when blast furnace slag with high volume is used as a partial replacement of cement. Test results showed that the addition of waste oil in the concretes decreased slump and air content, but further reduction was not observed as the amount of the waste oil further increased. In addition, the waste oil had a little impact on deteriorating the compressive strength of the concretes.

This paper is to investigate the effect of heat curing method on strength development of concrete subjected to -10℃ by preparing mock up specimen, which had slab, wall and column. As expected, the application of heat curing methods had larger strength than non heat curing specimen because of higher maturity. And within 7 days of heat curing, minimum strength to protect from early frost damage was achieved.

In this paper, microscopic observation of the high strength concrete subjected to elevated temperature ranged from 300~900℃ was conducted by applying SEM and MIP. According to results, an increase of temperature above 300℃ resulted in an increase of microcrack, which makes the accumulative pore amount increased.

The objective of the paper is to experimentally investigate the compressive strength of the concrete incorporating fly ash. Ordinary Portland cement(OPC). Water to binder ratio(W/B) ranging from 30% to 60% and curing temperature ranging from -10℃∼65℃ were also adopted for experimental parameters. Fly ash was replaced by 30% of cement contents. According to the results, strength development of concrete contained with fly ash is lower than that of plain concrete in low temperature at early age and maturity. In high curing temperature, the concrete with fly ash has higher strength development than that of low temperature regardless of the elapse of age and maturity. Fly ash can have much effect on the strength development of concrete at the condition of mass concrete, hot weather concreting and the concrete products for the steam curing.

본 연구는 화재시 고강도 콘크리트의 폭렬발생에 대한 영향요인을 검토한 것으로써, 폭렬에 직접적인 상관관계에 있는 물-결합재비, 공기량 및 함수율 등을 PP섬유의 혼입률과 함께 변화시켜 실험을 실시하였다. 실험결과 유동특성은 섬유의 혼입률이 0.05 vol.% 증가함에 따라 약 11%정도 감소하는 것으로 나타났고, 공기량이 10%인 경우는 다량의 AE제 사용에 기인하여 섬유의 혼입률과 상관없이 거의 유사한 유동성을 나타냈다. 강도특성으로는 W/B 15, 25 및 35%일 경우 100, 80 및 60 MPa이상으로써 고강도 범위로 나타났으며, 공기량 변수의 경우는 H-air가 L-air에 비해 약 1/2배 정도로 낮게 나타났다. 폭렬특성으로는 KS F 2257-1에 규정되어 있는 표준가열곡선에 의해 1시간 내화시험을 실시한 결과, W/B는 고강도로 W/B가 낮을수록 심하게 발생하는데, 15%를 제외한 모든 경우에서 전반적으로 PP섬유의 혼입률 0.10 vol.%에서 폭렬이 방지되는 것으로 나타났고, 공기량을 10%로 많이 함유하는 시험체와 완전건조 시킨 시험체는 0.05 vol.% 혼입시에도 폭렬현상이 발생하지 않는 것으로 나타났다.

In this paper, estimation of the compressive strength of the concrete incorporating blast furnace slag subjected to high temperature was discussed. Ordinary Portland cement and blast furnace slag cement (BSC;30% of blast furnace slag) were used, respectively. Water to binder ratio ranging from 30% to 60% and curing temperature ranging from 20℃～65℃ were also chosen for the experimental parameters, respectively. At the high temperature, BSC had higher strength development at early age than OPC concrete and it kept its high strength development at later age due to accelerated latent hydration reaction subjected to high temperature. For the strength estimation, the Logistic model based on maturity equation and the Carino model based on equivalent age were applied to verify the availability of estimation model. It was found that fair agreements between calculated values and measured values were obtained evaluating compressive strength with logistic curve. The application of logistic model at high temperature had remarkable deviations in the same maturity. Whereas, the application of Carino model showed good agreements between calculated values and measured ones regardless of type of cement and W/B. However, some correction factors should be considered to enhance the accuracy of strength estimation of concrete.

In this paper, removal time of side form from concrete using OPC(ordinary Portland cement) and FAC(fly ash cement) are proposed by appling logistic model, which evaluates the strength development of concrete with maturity. W/B, types of cement and curing temperatures are adapted as test parameters. The estimation of strength development by logistic model has a good agreement between calculated values and measured ones. As for the removal times of form works suggested in this paper, as W/B increases, curing temperature decreases and fly ash is used, removal time of side form is prolonged. Removal time of form from concrete using OPC suggested in this paper is shorter 2.5～3.5 days than those of KASS-5 (Korean Architectural Standard Specifications-5) in the range of over 20℃. And in the range of 10～20℃removal time of form is shorter than that of KASS-5 by as much as 4~4.5 days. The use of FAC results in an increase in removal time of form compared to that of OPC by about 1 day.