JNTINC Co.

Hwaseong, South Korea

JNTINC Co.

Hwaseong, South Korea
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Lee B.J.,JNTINC Co. | Kee S.-H.,Dong - A University | Oh T.,Incheon National University | Kim Y.-Y.,Chungnam National University
Advances in Materials Science and Engineering | Year: 2017

The objectives of this study are to investigate the relationship between static and dynamic elastic moduli determined using shear-wave velocity measurements and to demonstrate the practical potential of the shear-wave velocity method for in situ dynamic modulus evaluation. Three hundred 150 by 300 mm concrete cylinders were prepared from three different mixtures with target compressive strengths of 30, 35, and 40 MPa. Static and dynamic tests were performed at 4, 7, 14, and 28 days to evaluate the compressive strength and the static and dynamic moduli of the cylinders. The results obtained from the shear-wave velocity measurements were compared with dynamic moduli obtained from standard test methods (P-wave velocity measurements according to ASTM C597/C597M-16 and fundamental longitudinal and transverse resonance tests according to ASTM C215-14). The shear-wave velocity measured from cylinders showed excellent repeatability with a coefficient of variation (COV) less than 1%, which is as good as that of the standard test methods. The relationship between the dynamic elastic modulus based on shear-wave velocity and the chord elastic modulus according to ASTM C469/C469M was established. Furthermore, the best-fit line for the shear-wave velocity was also demonstrated to be effective for estimating compressive strength using an empirical relationship between compressive strength and static elastic modulus. © 2017 Byung Jae Lee et al.


Bang J.W.,Tongyang Construction Materials Co. | Lee B.J.,JNTINC Co. | Kim Y.Y.,Chungnam National University
Advances in Materials Science and Engineering | Year: 2017

Mechanical tests were carried out to evaluate the influence and effects of fluidity and compressive strength of cement grout on semirigid asphalt pavement. An open graded asphalt skeleton was designed in order to achieve target porosity in the range of 1822%. In addition, four types of cement grout mixtures were produced with varying mix proportions with ultrarapid hardening cement and chemical admixtures, that is, accelerating and retarding agents. For the semirigid pavement specimens, mechanical experiments to measure properties such as porosity, flexural strength, Marshall stability, and wheel tracking resistance were carried out. The test results demonstrated that the flow time (fluidity) of cement grout is the most significant factor that determines the mechanical properties of semirigid asphalt specimens under constant condition of the open graded asphalt skeleton. For the semirigid pavement mixing proportion in the current study, it is recommended that the porosity of the open graded asphalt skeleton and flow time of cement grout should be 20% and within 12 seconds, respectively. © 2017 Jin Wook Bang et al.


Lee B.J.,JNTINC Co. | Prabhu G.G.,KPR Institute of Engineering and Technology | Lee B.C.,Korea Conformity Laboratories | Kim Y.Y.,Chungnam National University
Waste Management and Research | Year: 2016

This article presents the test results of an investigation carried out on the reuse of coal bottom ash aggregate as a substitute material for coarse aggregate in porous concrete production for marine ranch applications. The experimental parameters were the rate of bottom ash aggregate substitution (30%, 50% and 100%) and the target void ratio (15%, 20% and 25%). The cement-coated granular fertiliser was substituted into a bottom ash aggregate concrete mixture to improve marine ranch applications. The results of leaching tests revealed that the bottom ash aggregate has only a negligible amount of the ten deleterious substances specified in the Ministry of Environment - Enforcement Regulation of the Waste Management Act of Republic Korea. The large amount of bubbles/air gaps in the bottom ash aggregate increased the voids of the concrete mixtures in all target void ratios, and decreased the compressive strength of the porous concrete mixture; however, the mixture substituted with 30% and 10% of bottom ash aggregate and granular fertiliser, respectively, showed an equal strength to the control mixture. The sea water resistibility of the bottom ash aggregate substituted mixture was relatively equal to that of the control mixture, and also showed a great deal of improvement in the degree of marine organism adhesion compared with the control mixture. No fatality of fish was observed in the fish toxicity test, which suggested that bottom ash aggregate was a harmless material and that the combination of bottom ash aggregate and granular fertiliser with substitution rates of 30% and 10%, respectively, can be effectively used in porous concrete production for marine ranch application. © The Author(s) 2015.


Lee B.-J.,JNTINC Co. | Lee J.,Korea Conformity Laboratories | Jang Y.-I.,Chungnam National University
Contemporary Engineering Sciences | Year: 2015

This study examined the physical and mechanical properties as well as the marine organism adhesion characteristics of the porous concrete that used recycled aggregate and specially treated granular fertilizer in order to present fundamental data for the effective use of recycled aggregates that were generated as byproducts of construction and for field application of the porous concrete used for the restoration of the marine ecosystem. The experimental results showed that the difference between the target void ratio and actually measured void ratio was approximately 2.0% and that the compressive strength tended to decrease rapidly when the target void ratio and recycled aggregate mixing ratio exceeded 20% and 50%, respectively. In addition, the adhesion ability of marine organisms to porous concrete was superior when the target void ratio was greater than 20% and the influence on the adhesion ability according to the mixing of recycled aggregates was insignificant. Moreover, it was observed that the adhesion ability of marine organisms improved when the specially treated granular fertilizer was mixed. Therefore, the appropriate target void ratio of 20% and the recycled aggregate mixing ratio of 50% are thought to be effective when considering the strength of the porous concrete for marine ecosystem restoration and the adhesion characteristics of marine organisms. © 2015 Buung-Jae Lee et al.


PubMed | KPR Institute of Engineering and Technology, Chungnam National University, Korea Conformity laboratories and JNTINC Co.
Type: Journal Article | Journal: Waste management & research : the journal of the International Solid Wastes and Public Cleansing Association, ISWA | Year: 2016

This article presents the test results of an investigation carried out on the reuse of coal bottom ash aggregate as a substitute material for coarse aggregate in porous concrete production for marine ranch applications. The experimental parameters were the rate of bottom ash aggregate substitution (30%, 50% and 100%) and the target void ratio (15%, 20% and 25%). The cement-coated granular fertiliser was substituted into a bottom ash aggregate concrete mixture to improve marine ranch applications. The results of leaching tests revealed that the bottom ash aggregate has only a negligible amount of the ten deleterious substances specified in the Ministry of Environment - Enforcement Regulation of the Waste Management Act of Republic Korea. The large amount of bubbles/air gaps in the bottom ash aggregate increased the voids of the concrete mixtures in all target void ratios, and decreased the compressive strength of the porous concrete mixture; however, the mixture substituted with 30% and 10% of bottom ash aggregate and granular fertiliser, respectively, showed an equal strength to the control mixture. The sea water resistibility of the bottom ash aggregate substituted mixture was relatively equal to that of the control mixture, and also showed a great deal of improvement in the degree of marine organism adhesion compared with the control mixture. No fatality of fish was observed in the fish toxicity test, which suggested that bottom ash aggregate was a harmless material and that the combination of bottom ash aggregate and granular fertiliser with substitution rates of 30% and 10%, respectively, can be effectively used in porous concrete production for marine ranch application.


Kim Y.-Y.,Chungnam National University | Lee B.-J.,JNTINC Co. | Kwon S.-J.,Hannam University
Advances in Materials Science and Engineering | Year: 2014

Diffusion coefficient from chloride migration test is currently used; however this cannot provide a conventional solution like total chloride contents since it depicts only ion migration velocity in electrical field. This paper proposes a simple analysis technique for chloride behavior using apparent diffusion coefficient from neural network algorithm with time-dependent diffusion phenomena. For this work, thirty mix proportions of high performance concrete are prepared and their diffusion coefficients are obtained after long term-NaCl submerged test. Considering time-dependent diffusion coefficient based on Fick's 2nd Law and NNA (neural network algorithm), analysis technique for chloride penetration is proposed. The applicability of the proposed technique is verified through the results from accelerated test, long term submerged test, and field investigation results. © 2014 Yun-Yong Kim et al.


Lee B.J.,JNTINC Co. | Bang J.W.,Chungnam National University | Shin K.J.,Chungnam National University | Kim Y.Y.,Chungnam National University
Materials | Year: 2014

In this study, adiabatic temperature rise tests depending on binder type and adiabatic specimen volume were performed, and the maximum adiabatic temperature rises and the reaction factors for each mix proportion were analyzed and suggested. The results indicated that the early strength low heat blended cement mixture had the lowest maximum adiabatic temperature rise (Q∞) and the ternary blended cement mixture had the lowest reaction factor (r). Also, Q and r varied depending on the adiabatic specimen volume even when the tests were conducted with a calorimeter, which satisfies the recommendations for adiabatic conditions. Test results show a correlation: the measurements from the 50L specimens were consistently higher than those from the 6L specimens. However, the Q∞ and r values of the 30L specimen were similar to those of the 50L specimen. Based on the above correlation, the adiabatic temperature rise of the 50L specimen could be predicted using the results of the 6L and 30L specimens. Therefore, it is thought that this correlation can be used for on-site concrete quality control and basic research. © 2014 by the authors.


Lee J.-W.,Chungnam National University | Jang Y.-I.,Chungnam National University | Lee B.-J.,JNTINC Co. | Park W.-S.,Chungnam National University
Key Engineering Materials | Year: 2016

This study evaluated the durability of concrete produced with a cementless binding material and potassium hydroxide (KOH) based on ground granulated blast furnace slag and fly ash. These industrial byproducts are used to replace cement in order to reduce carbon dioxide emissions. The test conducted for the freezing and thawing resistance of concrete using cementless binding material revealed that the relative dynamic modulus was 83.4%. From the results of a chemical resistance test, the mass reduction rate stood at 12.3% for the 5% HCl solution and 12.7% for the 5% H2SO4 solution, showing better chemical resistance than concrete using cement. The depth of neutralization was observed to be 4.48mm, a similar level to that of cement-containing concrete. © (2016) Trans Tech Publications, Switzerland.


Lee B.J.,JNTINC Co. | Kim J.S.,Korea Institute of Construction Technology | Jang Y.I.,Chungnam National University
Key Engineering Materials | Year: 2016

In this study, the optimal mixing conditions for recycled cold asphalt, which recycled waste asphalt and used cementless binders, was assessed through verification of the performance. The cementless binder mixing ratio of 6% desulfurization gypsum substitution rate for blast furnace slag was found to have the most outstanding properties. For the Marshall stability, 4% filler mixing brought about a 1.92 times strength increase effect compared to OPC. The flow value testing showed that an increase in the use of asphalt emulsion resulted in an increased flow value while it decreased with the increase in filler substitution rate. The optimal mixing condition that satisfied mechanical performance and durability among the test conditions assessed in this study was found to be 4% filler mixed. © (2016) Trans Tech Publications, Switzerland.


Jang Y.I.,Chungnam National University | Park W.-S.,Chungnam National University | Kim S.-w.,Chungnam National University | Lee B.-J.,JNTINC Co.
Contemporary Engineering Sciences | Year: 2015

For increased recycling of waste asphalt concrete and reduced generation of CO2, this study evaluated the stability and durability performance of cold-recycled asphalt that used cementless binders and polymers. For cementless binders, the present study used powder added with 80% ground granulated blast furnace slag (BFS) and fly ash, with the optimal mixture ratio derived from prior experiments. According to the test results, as the addition of polymers increased, Marshall stability increased but the flow values decreased. Abrasion resistance and dynamic stability (DS) were superior for specimens that used cementless binders and polymers than for those that used OPC. In particular, at room temperature of20°C, deflection in the center of the test specimens decreased, and the deformation rate and DS were measured to be 0.0007 mm/min and 63,000 times/min, respectively. © 2015 Young-Il Jang et al.

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