PURPOSES : The purpose of this study was to improve the performance of concrete pavements by measuring the unit-water content with an Internet-of-Things (IoT)-based unit-water content measurement device at an increased precision compared with that of existing measuring equipment. METHODS : We calculated the properties of concrete that varied according to variations in the unit-water content. To confirm the change in the performance of concrete pavements, we compared and analyzed the fatigue cracking rate and international roughness index of concrete pavements at the 20-year point of public use according to the changes in properties using the Korea Pavement Research Program(KPRP). RESULTS : We confirmed that IoT-based measurement equipment can improve the performance of pavements without changing their mixing designs or specifications. We confirmed that the performance of the concrete pavements changed significantly, even with unit-water content variations within the range of quality standards. According to IoT-based unit-water content management, we confirmed that the performance of the concrete pavement (fatigue cracking rate and international roughness index) improved without changing the mixing design. CONCLUSIONS : We confirmed that by using IoT-based unit-water content management, pavement performance can be improved. It is necessary to consider whether the application of this concept to other concrete property management items, such as the chloride content, is possible. Considering the changes in concrete properties according to the unit-water content based on laboratory tests and considerations of various load conditions will be necessary for future research.

Objective of this study was to evaluate the carbon budget on 40 years old pear orchard at Naju. For carbon budget assessment, we measured the soil respiration, net ecosystem productivity of herbs, pear biomass and net ecosystem exchange. In 2015, pear orchard released about 25.6 ton CO2 ha-1 by soil respiration. And 27.9 ton CO2 ha-1 was sequestrated by biomass growth. Also about 12.6 ton CO2 ha-1 was stored at pruning branches and about 5.2 ton CO2 ha-1 for photosynthesis of herbs. As a result, 25.6 ton of CO2 per ha is annually released to atmosphere. At the same time about 45.7 ton of CO2 was sequestrated from atmosphere. When it sum up the amount of CO2 release and sequestration, approximately 20.1 ton CO2 ha-1 was sequestrated by pear orchard in 2015, and it showed no significant differences with net ecosystem exchanges (17.8 ton CO2 ha-1 yr-1) by eddy covariance method with the same period. Continuous research using various techniques will help the understanding of CO2 dynamics in agroecosystem and it can be able to present a new methodology for assessment of carbon budget in woody crop field. Futhermore, it is expected that the this study can be used as the basic data to be recognized as a carbon sink.

We have developed a DH-PROTO equipment to measure the Unit-Water Content of concrete. In this paper, using an accredited certification HI-330 and developed DH-PROTO to measure the Unit-Water Content, it was evaluated by comparing the measurement stability. In experimental results by using a capacitive equipment DH-PROTO and HI-330, Estimation error of DH-PROTO and HI-330 according to the type of binder is -4.4 to 2.0%, -7.4 to 4.0%, measuring equipment for Unit-Water Content in concrete showed excellent performance in reliability assessment measures. Also, the estimation error according to the type of fine aggregate was appeared to 3.4~10.4 % and 2.8~9.1%, was determined that excellent performance and accuracy levels with it. Thus, it expected to be released as a commercial product through further studies.

This study was conducted examine the workability of LEFC in relation to unit quantity of water and fiber addition. The LEFC should secure low weight and good flow by mixing light weight aggregate because the fresh concrete should cured so that gaps do not form between the acrlyic wedges and the concrete with the fresh. The slump tests revealed that fresh concrete with 180 units of water and 0.1% fiber content and fresh concrete with 190 units of water and 0.1%, 0.2% fiber content respectively had excellent workability.

This study was conducted examine the workability of LEFC in relation to unit quantity of water and fiber addition. The LEFC should secure low weight and good flow by mixing light weight aggregate because the fresh concrete should cured so that gaps do not form between the acrlyic wedges and the concrete with the fresh. The slump tests revealed that fresh concrete with 180 units of water and 0.1% fiber content and fresh concrete with 190 units of water and 0.1%, 0.2% fiber content respectively had excellent workability.

This study was examined the variation of unit water content and fine aggregate ratio in concrete for nuclear power structure using a large amoung of crushed sand.

Dry shrinkage of concrete is occurred due to the cement hydration and water evaporation from early ages, and it induces crack of concrete. In this study, shrinkage according to sand-aggregate and water-binder ratio were compared with the existing prediction models. From the results, when sand-aggregate ratio and unit water content increase, dry shrinkage of concrete increase. But, it showed that existing prediction models do not reflect shrinkage of concrete, well.

콘크리트내의 공극률은 콘크리트 구조물의 내구적인 특성과 밀접한 관련성이 있다. 특히, 콘크리트 시공시 가수된 물은 콘크리트의 비빔과 작업성에 일시적으로 도움이 되지만, 이러한 가수는 콘크리트의 공극을 증가하게 하며, 이는 콘크리트 구조물의 내구적인 성능저하를 야기하게 된다. 본 연구에서는 물시멘트비 0.45의 시멘트 모르타르에 대하여, 단위수량을 증가시켜 물멘트비를 0.45에서 0.60으로 증가시키면서 내구성능을 평가하였다. 즉, 각 물시멘트별로 소정의 재령까지 양생한 시험체에 대하여 강도, 염화물 확산, 투기성, 포화도 및 수분 확산계수 등의 다양한 내구성 실험을 수행하였으며, 이러한 실험결과들은 변화하는 공극률과 함께 분석되었다. 또한 내구성능의 변화 비율 및 그 패턴은 공극분포, 공극률, 그리고 단위수량을 고려하여 정량적으로 평가되었다.

lndoor landscape plays important roles in the environmental improvements of inner building and play leading roles in offering green space to urban communities. as proffessionally part of technically construction, constucting indoor landscape, we have to frame the standard of materials and the standard of materials and the construction expanses because the demand of indoor landscape have risen increasingly. Especially, indoor landscape have kept in being paltry and unproffesionalty under the present condition of no standards about the estimation of proper construction expenses, Also, when Unit Cost chart is made, there are no indicators or specific standards that evaluate unit price. So this study carried out to suggest the evaluating standards of plantings pen some areas. It can be the basis work of the making out the proper constructional expenes The progresses and details of this study were the followings -first, the list of indoor plants and the standard of planter were suggested, through case study of indoor landscape and blue-drawings. -second, the quantity of planting materials according to each standardized planter was suggested through the theoretical and numeric methods, the existed unit cost charts and survey of several indoor landscapes -third, the quantity of typical planting materials according to each standized planter was also suggested. The result of this study were the followings. -the quantities per unit area of indoor ground cover flowing plants were 176/ m' in case of 3 chi planter of the type of upper growing, 127 I m' in case of 3 chi planter of the type of side growing. They were 94/ m2, 51/ m2, 38/ m2, 28/ m2 in order 4 chi, 5 chi, 7 chi, 7 chi planter of type of upper growing. Also they were found out 67/m2, 32/ m2, 24/ m2, 18/ m2 in order 4, 5, 6, and ?chi planter of the type of side growing. This study have several limits suggesting only the quantity of plants per unit area, to make out unit cost. llereafter this study will be developed to suggest the unit standard and unit cost of the other materials besides planting materials in indoor landscape. And the labor cost per unit materials will be developed through the next studies on the basis of the result of this study.