PURPOSES: In this study, the effects of adding a superabsorbent polymer (SAP) to the concrete mixture on the strength of the concrete and abrasion resistance were analyzed, and whether the property of concrete can be improved by the internal curing effect of SAP was evaluated. METHODS: In this study, a total of eight different mixes were tested. The amounts of SAP added were 0%, 0.6%, 1.2% while that of silica fume were 0% and 6% based on the weight of the binder. The compressive test, rapid chloride penetration resistance test, and abrasion test were performed to verify the internal curing effects of SAP. RESULTS : The compressive test showed that SAP concrete had greater compressive strength than ordinary concrete. Comparison of the compressive strengths of dry and wet cured specimens of each mixture showed that SAP concrete had a smaller difference compared with ordinary concrete. The rapid chloride resistance test showed that SAP did not increase chloride penetration resistance. However, since this experiment only considered wet curing, further investigation of dry curing is necessary. The abrasion resistance test showed that for the case of concrete cured under dry conditions without spraying the curing compound, the abrasion resistance of the SAP concrete improved by approximately 49% at 14 days and 27% at 28 days of curing compared with ordinary concrete. CONCLUSIONS : The effect of SAP on the strength and abrasion resistance of concrete was analyzed. The results showed that the internal curing effect of SAP improved concrete strength and abrasion resistance. The internal curing effect maintains the overall internal humidity in concrete by supplying water held by the SAP to the dried cement paste.

PURPOSES: This paper develops a new stochastic approach to analyze the pavement-vehicle interaction model with a certain roughness and elasticity for the pavement foundation, thereby accommodating the deflection of the pavement, and to identify the road subsidence zone represented with a sudden changes in the elasticity of the foundation. METHODS: In the proposed model, a quarter-car model was combined with a filtered white noise model of road roughness and a two-layer foundation (Euler-Bernoulli beam for the top surface and Winkler foundation to represent the sub-structure soil). An augmented state-space model for the subsystems was formulated. Then, because the input is White noise and the system is represented as a single system, the Lyapunov equation governing the covariance of the system’s response was solved to obtain a structurally weak zone index (WZI). RESULTS: The results showed that the WZI from the pavement-vehicle interaction model is sensitive enough to identify road subsidence. In particular, the WZI rapidly changed with a small change in foundation elasticity, indicating that the model has the potential to detect road subsidence in the early stage. CONCLUSIONS: Beacause of the simplicity of the calculation, the proposed approach has potential applications in managing road conditions while a vehicle travels along the road and detecting road subsidence using a device with an on-board computational capability, such as a smart phone.

유기용매 나노여과(OSN, organic solvent nanofiltration) 분리막은 폴리이마이드(PI)나 폴리벤질이미디아졸(PBI)과 같은 특수 고분자의 개발, 상업화가 이루어지고 강한 유기용매에 견딜 수 있도록 가교를 통해 분리막의 내구성이 급격하게 향상되면서 저분자량의 합성, 정제 및 농축을 필요로하는 의약, 바이오, 식품산업에 획기적이고 효율적인 분리막 공정으로 주목 받고 있다. 하지만 여전히 고가의 고분자, 가교를 위한 복잡한 프로세스, 다량의 강한 용매 폐수 발생등 상업화를 이루는데 여러 가지 문제점들이 산재하고 있다. 본 연구는 기존 제막 방식에서 벗어나 무독성의 용제를 사용하여 단일공정으로 유기용매 나노여과 분리막을 제막하고 그 특성을 연구하였다.

유기용매 나노여과(OSN, organic solvent nanofiltration) 분리막은 폴리이마이드(PI)나 폴리벤질이미디아졸(PBI)과 같은 특수 고분자의 개발, 상업화가 이루어지고 강한 유기용매에 견딜 수 있도록 가교를 통해 분리막의 내구성이 급격하게 향상되면서 저분자량의 합성, 정제 및 농축을 필요로하는 의약, 바이오, 식품산업에 획기적이고 효율적인 분리막 공정으로 주목 받고 있다. 하지만 여전히 고가의 고분자, 가교를 위한 복잡한 프로세스, 다량의 강한 용매 폐수 발생등 상업화를 이루는데 여러 가지 문제점들이 산재하고 있다. 본 연구는 기존 제막방식에서 벗어나 무독성의 용제를 사용하여 단일공정으로 유기용매 나노여과 분리막을 제막하고 그 특성을 연구하였다.

PURPOSES : The purpose of this study is to develop bridge deck concrete materials based on ordinary Portland cement concrete, and to evaluate the applicability of the developed materials through material properties tests.METHODS : For field implementation, raw material (cement, fine aggregate, and coarse aggregate) properties, fresh concrete properties (slump and air content), strength (compressive, flexural and bond strength) gain, and durability (freeze-thaw resistance, scaling resistance, and rapid chloride penetrating resistance) performance were evaluated in the laboratory.RESULTS: For the selected binder content of 410 kg/m3, W/B = 0.42, and S/a = 0.48, the following material performance results were obtained. Considering the capacity of the deck finisher, a minimum slump of 150 mm was required. At least 6 % of air content was obtained to resist freezethaw damage. In terms of strength, 51.28 MPa of compressive strength, 7.41 MPa of flexural strength, and 2.56 MPa of bond strength at 28 days after construction were obtained. A total of 94.9 % of the relative dynamic modulus of elasticity after 300 cycles of freeze-thaw resistance testing and 0.0056 kg/m2 of weight loss in a scaling resistance test were measured. However, in a chloride ion penetration resistance test, the result of 3,356 Coulomb, which exceeds the threshold value of the standard specification (1000 Coulomb at 56 days) was observed.CONCLUSIONS: Instead of using high-performance modified bridge deck materials such as latex or silica fume, we developed an optimum mix design based on ordinary Portland cement concrete. A test construction was carried out at ramp bridge B (bridge length = 111 m) in Gim Jai City. Immediately after the concrete was poured, the curing compound was applied, and then wet mat curing was applied for 28 days. Considering the fact that cracks did not occur during the monitoring period, the applicability of the developed material is considered to be high.

PURPOSES : It is necessary to clarify the rheological properties of cement paste as a basic research in the development of mechanistic concrete mix design. The rheological properties of cement paste with different binder types, mix propositions, and with/without high range water reducers have been analyzed. METHODS: In this study, ordinary Portland cement, fly-ash, blast furnace slag, silica fume, and limestone powder were used as binders. The range of water-binder ratio was 0.3-0.5, and a total of 30 different mixes have been tested. The slump flow test, V-funnel test, and Dynamic Shear Rheometer (DSR) test were performed to analyze the rheological properties of cement paste. RESULTS : As a result of the slump flow test, it was found that the composition ratio of the binder contents greatly affected the paste flow when the high range water reducers were added. The results of V-funnel test showed that when the water-binder ratio was decreased without high range water reducers, the binder composition ratio had a large effect on the passing time of the V-funnel tester, but with high range water reducers the impact of the binder composition ratio was decreased. The slump flow and V-funnel have a certain relationship with the rheological factors (yield stress and plastic viscosity), but the correlation was not significant. Finally, we proposed the M-value considering the density and specific surface area of the binder. The correlation between rheological factors and M-value were better demonstrated than experimental values, but there is still a limit to predict the rheological factor in general mix design. CONCLUSIONS: In this study, the rheological properties of cement paste were analyzed. The binder type, composition ratio of binder, and with/without high range water reducers have combined to provide the complex effects on the rheological properties of cement paste. The correlation between the proposed M-value and rheological factor was found to be better than experimental results, but needs to be improved in the future.

한국건설기술연구원은 국도 3호선 회천-상패 구간에 콘크리트포장의 장기공용성을 관측하기 위해 시험시공을 실시하였다. 포장단면은 JCP(줄눈콘크리트포장)와 CRCP(연속철근콘크리트포장)로 구성하였으며, JCP는 슬래브 두께를 20cm～30cm로 변화를 두어 3개 단면으로 구성하였고, CRCP는 슬래브 두께를 20cm, 25cm로 하여 2개 단면으로 구성하였다. 본 논문에서는 이 구간에 FWD(falling weight deflectometer)시험을 통해 단면별 처짐량 및 LTE(load transfer efficiency)를 분석하였다. 재하하중은 4.5ton으로 하였으며, 재하위치는 슬래브 중앙부와 줄눈부(또는 균열부)로 하였다. 또한 측정시간을 7시, 11시, 14시, 17시로 나누어 실험을 수행하였다. FWD 실험결과, CRCP 4단면(슬래브 두께 25cm)은 전체 5개 단면 중 시점에 따른 처짐량 변동폭이 가장 작았으며, 또한 균열사이 중앙부와 균열부의 처짐량 차이도 가장 작게 나타났다. 해당 단면의 경우 전체적으로 슬래브 중앙부 D0 처짐량이 약 70～80 ㎛를 나타내었다. JCP 1단면(슬래브 두께 30cm)의 슬래브 중앙부 처짐량은 약 60～90㎛을, JCP 2단면(슬래브 두께 25cm)는 약 80～100㎛을, JCP 3단면(슬래브 두께 20cm)은 120～220㎛ 정도를 나타내고 있어, 슬래브 두께가 얇아질수록 슬래브 중앙부 처짐량은 증가하는 것으로 나타났다. CRCP 단면의 균열 사이 중앙부 처짐량 변동이 재하시점에 따라 최대 약 10㎛ 정도로 나타났는데, 상대적으로 JCP의 슬래브 중앙부 처짐량 변동은 CRCP 보다 더 큰 것으로 나타났다. 특히 JCP 슬래브 두께가 얇을수록 변동폭이 더 증가하는 것으로 나타났다. CRCP 균열부의 LTE가 모든 시점에서 90% 이상을 나타내어 상당히 우수한 것으로 평가되었으며, JCP 줄눈부의 경우 대체적으로 약 80% 이하를 나타내었다. 또한 JCP의 경우 줄눈부에 따라 LTE가 크게 변동하는 것으로 나타나 줄눈부 시공품질의 변동성이 큰 것으로 분석되었다. 또한 재하 시점에 따른 LTE 변동은 크지 않은 것으로 분석되었다. 이와 같은 결과를 볼 때, JCP의 경우 슬래브 상하단 온도 차이에 따른 상향컬링과 하향컬링이 슬래브 처짐량에 영향을 크게 미치지만, 이것이 LTE에 영향을 미치지 않는 것으로 나타났다.

PURPOSES : The purpose of this study is to verify the property of self-healing, and to propose an appropriate duration for wet curing of bridge deck concrete overlays. METHODS: In this study, reinforced bars were inserted into concrete molds in order to prevent brittle fracture and induced cracks in the concrete resulting from indirect tension mode. The induced time of concrete cracking was 3 to 7 days, following which the concrete specimens were cured in water. The resulting concrete crack width was measured using image analysis equipment. Additionally, the self-healing tests were performed using the following three mixtures: OPC, SFC, and LMC. RESULTS: Concrete mixtures with crack widths of 150㎛ or lower were completely healed by Day 28. Hydrates of crack fills were found to be the calcium carbonate. CONCLUSIONS: The cement-based mixtures exhibit properties of self-healing. Considering these properties, it is necessary to increase the curing duration of concrete overlays for bridge decks.

PURPOSES : The objective of this study is to develop an optimized method of mix design for rapid-set lightweight-formed mortar mix. To achieve this objective, the workability, setting time, and compressive strength of mixes under various conditions of mix design were evaluated. METHODS: The water-bonder ratio, fly-ash substitution ratio, and forming agent injection amount were selected as design variables in the study. The fluidity, setting time, density, and strength of the mortar mix were considered as major evaluation criteria of the mixture, and were subsequently utilized to evaluate the characteristics of the mortar mix under various conditions. RESULTS : The observations made from the mix design process are as follows: 1) the air content and fluidity increase as the forming agent ratio and forming agent ratio increase, respectively; 2) the maximum air content is approximately 20%; 3) the accelerating agent decreases the fluidity of the mortar mix by 15% on average; 4) the forming agent injection ratio and fly-ash substitution ratio yield significant effects on the initial and final set times of the mortar mix; 5) as the forming agent injection ratio and fly-ash substitution ratio increase, the compressive strength of the mortar mix decreases; and 6) the 28-day compressive strengths of the forming agent injection ratio and fly-ash substitution ratio yield the most significant effects. CONCLUSIONS: It is concluded that the governing design variables for the rapid-set lightweight-formed mortar mix are the forming agent injection ratio and fly-ash substitution ratio.

도심지내 굴착복구 공사는 시간과의 싸움이다. 서울시의 경우 당일굴착, 당일복구를 원칙으로 하고 있 다. 이로 인해 작업자는 제안된 시간내에 굴착복구 공사를 마무리 하여야 한다. 굴착공정 상 굴착시간과 관로 시공에는 작업시간을 많이 할당 하지만, 되메우는 공정(모래부설 및 다짐, 골재부설 및 다짐)에는 상 대적으로 시간 할당이 적은 편이다. 그러다 보니 되메우는 과정에서 충분한 다짐을 할 시간적 여유가 없 으며, 결국 임시포장으로 마무리 한 다음 추후에 다시 포장공사를 하는 실정이다. 이에 본 연구에서는 관 로 주변의 충분한 지지력 확보 및 작업성을 위하여 경량기포 모르타르를 적용하였으며, 최적 작업시간 산 정을 위한 최적배합을 도출하고자 하였다. 최적배합을 설정하기 위한 변수로 물-결합재 비(W/B), 플라이애시 치환율 및 기포 투입 시간을 설정하 였다. 물-결합재비는 60, 65, 70%로 플라이애시 치환율은 결합재 질량 대비 60, 70, 80%, 기포투입시간 은 0, 1, 2초로 설정하였다. 초결시간을 결정하기 위한 모르타르의 응결시험은 KS F 2436“관입 저항침에 의한 콘크리트의 응결 시간 시험방법”에 따라 실험을 수행하였으며, 초결의 응결시간 계산을 위하여 회귀분석에 의한 방법을 사용하였다. 개별 함수별 상관관계를 분석한 결과, 플라이애시 치환율과 기포 투입시간이 초결에 영향을 미치는 것 으로 나타났으며 오히려 W/B비는 미치는 영향이 적은 것으로 나타났다. 이러한 결과의 원인으로는 W/B 비의 경우 최적 플로우를 만족시키기 위하여 고성능 감수제를 배합별로 차별화하여 적용하였다. 게다가 기포 투입량에 따라 유동성이 변하고 이로 인해 초결에 영향을 미칠 수 있다고 판단되었다. 또한 플라이 애시의 경우 강도 발현에 영향을 주는데 치환량이 증가할수록 강도 발현이 늦어지기 때문이다. 이러한 결 과는 변수별 컨투어 곡선을 분석해 봐도 알 수가 있다. 그림 2, 3의 경우 W/B비 에 따른 초결 시간 변화가 적은 것을 알 수 있다. 하지만 그림 1을 보면 플라 이애시 치환율와 기포투입시간에 따른 초결 시간 변화가 있는 것으로 나타났다. 특히 초결 시간을 최대한 짧게 만들 수 있는 최적 변수 범위는 플라이애시 치환율의 경우 70% 수준이고, 이에 따른 기포투입시간 은 2초 이하에서는 모두 적정한 것으로 나타났다.

콘크리트 교면포장에서 가장 주요한 파손의 형태가 균열이며, 그 원인은 대부분 수축에 있다. 만약 교면 포장에서 균열이 발생하면 불투수성기능을 확보하지 못하게 되며, 이로 인해 균열부로 수분 또는 염화물이 침투하고 장기적으로 교량 바닥판의 열화를 가져오게 된다. 이에 반해 교면포장용 콘크리트에 자기치유 (self-healing) 성능이 확보된다면 균열부위를 수화물로 되메움하여 교면포장의 기능을 회복시킬 수 있다. 최근 국내외 문헌에서 팽창재(expansion agent)를 첨가할 경우 콘크리트의 자기치유성능이 향상되는 것 으로 일부 보고가 되고 있다. 이에 본 연구에서는 팽창재를 첨가한 교면포장용 콘크리트의 자기치유 특성 을 분석하였으며, 이를 통해 교면포장의 공용성능을 향상시킬 수 있는지에 대한 검토를 수행하였다. 본 연 구에서는 6,000브레인 이상의 고분말도 플라이애시와 슬래그를 치환한 삼성분계 결합재에 팽창재를 0%, 4%, 8%, 12%를 첨가하여 콘크리트 배합을 실시하였으며, 자기치유실험은 간접인장모드로 재령 3일과 재 령 7일에 균열을 유도한 후 수침양생을 시키고 균열발생 시점부터 시간경과에 따른 자기치유특성을 분석 하였다. 균열폭을 측정을 위해 사용된 화상촬영기는 QICAM 디지털카메라(1.4 million, 1392×1040)에 현 미경렌즈(optical 0.5-5x)를 부착한 것이며, 시편이 자동으로 움직이면서 측정할 수 있는 stage를 장착하 였다. 촬영된 이미지는 ʻimage-pro 6.0ʼ분석프로그램을 사용하여, 균열폭을 정밀하게 측정하였다. 본 연구의 자기치유실험결과, 균열이 발생한 시료를 습윤한 상태로 유지한 경우 모든 배합에서 자기치 유현상이 나타났으며, 특히 균열폭이 150㎛ 이하인 콘크리트는 대부분 14일 또는 28일에 대부분 완전히 치유가 되는 것으로 나타났다. 또한 균열이 초기에 발생하고 습윤한 상태를 유지할 경우 팽창재를 첨가한 콘크리트가 균열부의 자기치유 시기를 앞당길 수 있는 것으로 나타났다. 특히 재령 3일에 균열을 유도한 경우 팽창재를 8% 이상 첨가한 콘크리트에서 폭이 약 150㎛ 이하의 균열들 중 상당수가 균열발생 이후 7일에 완전 치유되었다. 팽창재를 첨가하면 초기에 다량의 에트린자이트가 형성되는데 이것이 콘크리트 를 팽창시키는 효과로 작용하며, 이 효과가 자기치유성능을 증가시켰기 때문이다. 그러나 재령 7일 이후 에 발생된 균열의 경우 팽창재의 자기치유효과가 크지 않은 것으로 분석되었다.

PURPOSES : This study set out to investigate the fundamental properties of alkali-activated concrete (AAC) using modified slag as the pavement maintenance material. METHODS: The material properties of modified slag based alkali-activated concrete (MSAAC) were analyzed and evaluated against those of alkali-activated slag concrete (AASC). Several mix formulations were considered, including one MSACC and four AASCs. The main variables considered in the study were slump, air content, compressive strength, rapid chloride permeability test, scaling resistance, freeze-thaw test, XRD, SEM, and EDS. RESULTS: MSAAC exhibits a compressive strength in excess of 21 MPa six hours after curing. Also, the charge passed of the MSACC was found to be less than 2000 coulombs after seven days and about 1000 coulombs after 28 days. The weight loss determined from a scaling test did not exceed 1 kg/cm2 in the case of the MSACC, but that of the AASCs had already exceeded 1kg/cm2 at the 10th cycle. Based on the results of the freeze-thaw test, the relative dynamic modulus of every mix was found to be in excess of 90%. An energy dispersive spectroscopy(EDS) analysis found that the weight rate percentage of the calcium and aluminum in the MSAAC mix is twice that of the AASC mixes. CONCLUSIONS : It was found that the MSAAC mix exhibits significantly better performance than AASC mixes, based on various fundamental properties.

PURPOSES : The purpose of this study is to analyse the longitudinal steel strain and stress of continuously reinforced concrete pavement(CRCP) with longitudinal and transverse direction at early age using stress dependent strain analysis method. METHODS : To measure the longitudinal steel strain, 9-electrical resistance and self-temperature compensation gauges were installed to CRCP test section (thickness = 250mm, steel ratio = 0.7%) and continuously measured 10min. intervals during 30days. In order to properly analyze the steel stress first, temperature compensation process has been conducted. Secondly, measured steel strains were divided into stress dependent strain (elastic strain) and stress independent strain (thermal strain) and then stress dependent strain was applied to stress calculation of longitudinal steels. RESULTS: Steel strains were successfully measured during 30days. To verify the accuracy of temperature compensation process, measured coefficient of thermal expansion(COTE,11.46×10-6m/m/℃) of longitudinal steel before paving was compared with that of unrestrained steel. Max. steel stress in the transverse direction shows about 266MPa at 23days after placement. CONCLUSIONS: Steel stresses in the longitudinal and transverse direction have been evaluated. In longitudinal direction, steel stress from the crack was rapidly reduced from 183MPa at crack to 18MPa from 600mm apart the crack. From this observation, stress effective length can be identified as within 600mm apart from the crack. In transverse direction, max. stress point was located near the center of pavement width and stress level(266MPa) is about 66% of yield stress of steel

PURPOSES: The purpose of this study is to verify the causes of surface scaling at L-shoulder concrete structure. METHODS : From the literature reviews, mechanisms of frost damage were studied and material properties including strength, air void, spacing factor and scaling resistance of L-shoulder concrete structure were analyzed using core specimens taken by real fields. RESULTS : The spacing factor of air void has relatively high correlation of surface conditions : lower spacing factor at good surfacing condition and vice versa. If the compressive strength is high, even thought spacing factor does not reach the threshold value of reasonable durability, the surface scaling resistance shows higher value. Based on these test results, the compressive strength also provide positive effect on the surface scaling resistance. CONCLUSIONS: The main causes of surface scaling of L-shoulder could be summarized as unsuitable aid void amount and poor quality of air void structure. Secondly, although the compressive strength is not the governing factor of durability, but it shows the positive effect on the surface scaling resistance.

알칼리 활성 시멘트 콘크리트는 비소성 무기결합재와 알칼리 활성제를 사용하여 제조된 콘크리트를 의 미하며, 알칼리 활성 슬래그 기반 콘크리트 ․ 플라이애시 기반 지오폴리머(Geopolymer) 등을 포함하는 넓 은 범주의 의미로 사용된다. 비소성 무기결합재에는 플라이애시, 고로슬래그, 메타카올린, 점토 등이 많 이 사용되며, 최근에 성능향상을 위해 실리카흄을 일부 사용하기도 한다. 알칼리 활성 콘크리트는 결합재의 타입에 따라 요구되는 알칼리 활성제의 양도 달라지며, 또한 그 방응 생성물도 큰 차이를 보인다. 또한 알칼리 활성제 에 따라 강도발현특성을 조절할 수 있는 장점이 있어, 이 러한 특성을 이용한다면 콘크리트 유지보수재료로 활용이 가능하다. 그러나 그동안 많은 연구자들에 의해 건조수축이 크고, 조기탄산화에 따른 균열이 발생할 수 있으며, 결합재의 품질변동성이 크다는 단점이 지 적되어 왔다. 이와 함께 도로포장에서 중요하게 평가되는 내구성능과 관련하여서는 기존 연구가 많이 이 루어지지는 않았다. 본 연구에서는 알칼리 활성 콘크리트의 강도발현과 내구특성 비교를 통해, 도로포장 유지보수재료로 활 용이 가능한지에 대한 적용가능성 여부를 평가하였다. 본 연구에서는 결합재 타입 및 구성에 따른 알칼리 활성 콘크리트의 물성특성을 분석하였으며, 그 결과를 그림 1과 2에 나타내었다. 그림에서 나타내 것과 같 이 일반 슬래그 기반 알칼리 활성 콘크리트의 경우에는 24시간에 압축강도 21MPa 이상을 나타내었으나, 개질슬래그 기반 콘크리트의 경우 6시간 안에 21MPa이상을 나타내어 조기강도발현 특성이 우수한 것으로 평가되었다. 장기강도 측면에서는 일반 슬래그 기반 콘크리트가 더 우수한 것으로 나타났다. 또한 염소이 온침투저항성 실험결과에서는 개질슬래그 기반 콘크리트가 일반슬래그 기반 콘크리트에 비해 투수저항성 이 상당히 우수한 것으로 나타났다. 특히 개질슬래그 기반 콘크리트의 경우 재령 7일에 2,000쿨롱이하, 28일에 약 1,000쿨롱 정도로 측정되어 콘크리트 유지보수재료 품질기준을 만족하는 것으로 나타났다. 이 외에 표면박리저항성 실험결과에서도 개질슬래그 기반 알칼리 활성 콘크리트가 가장 박리량이 적었으며, 특히 실험종료 후 박리량이 1kg/㎡ 이하를 나타내어 박리저항성이 상당히 우수한 것으로 평가되었다.

PURPOSES: This study is to compare load transfer efficiency of key joint and dowel joint for airport concrete pavement. METHODS: As AC150/5320-6D of FAA’s [Advisory Circular] was changed into AC150/5320-6E, Key joint type of rigid pavement were excluded from Construction Joints.. LTE(Load Transfer Efficiency) of dowel joint and key joint were compared by times and seasons through pavement temperature measurement, ocular investigation and HWD measurement. RESULTS: For the joint performance grade of No. 2(The second) runway of airport, 12% of poor rate was observed in key joint and 2% of poor rate in dowel joint. Poor rate of key joint was increased to 17%, if only No. 3~No. 6 slabs, which are mostly loaded from the airplanes, were applied for the study. In apron area, LTE poor rate of key joint was high in winter, and LTE poor rate of dowel joint was at least above ‘Fair’ grade. In summer, ‘Fair’ for key joint, ‘Acceptable’ for dowel joint appeared. CONCLUSIONS : As results, dowel joint was superior than key joint for LTE. Deviations of seasons and times were smaller in dowel joint’s result. And LTE in winter was lower than LTE in summer.

PURPOSES : The purpose of this study is to evaluate the durability of ternary blended concrete mixtures adding ultra fine admixture. METHODS : From the literature review, crack was considered as the main distress failure criterion on concrete bridge deck pavement. To reduce the initial crack development due to drying shrinkage, CSA expansion agent and shrink reduction agent were used to ternary blended concrete mixtures as a admixture. Laboratory tests including chloride ion penetration test, surface scaling test, rapid freeze & thaw resistance test, non restrained drying shrinkage and restrained drying shrinkage test were conducted to verify the durability of ternary blended concrete mixtures. RESULTS : Based on the test results, proposed mixtures were verified as high qualified durable materials. Expecially initial drying shrinkage crack was not occurred in ternary blended concrete mixtures with CSA expansion agent. CONCLUSIONS : It is concluded that the durability of proposed ternary blend concrete mixture was acceptable to apply for the concrete bridge deck pavement.

PURPOSES : This study is to evaluate ASR(alkali silica reactivity) resistance of ternary blended binder adding ultra fine mineral admixture. METHODS : This study analyzes ASR expansion using ASTM C 1260 and 1567. RESULTS : This study showed that the fineness of mineral admixture had no effect on ASR expansion. The expansion of ternary blended binder(UFFA 20%+FGGBS 10%) were below 0.1%, and this binder met the ASR standard. Also when adding the CSA expansion agent, ASR expansion slightly decreased. The expansion of latex modified mixture increased by 80% comparing plain mixture. CONCLUSIONS : Ternary blended binder met the ASR standard, and this binder is available in concrete bridge deck overlay.