• Journal of the Korean Geosynthetics Society
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• v.13 no.3
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• pp.21-30
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• 2014

In this study, the applicability of the lightweight dynamic cone penetrometer in the domestic slope site was investigated using the weathered granite soil sampled form the Namwon slope site. And then, the lightweight dynamic cone penetration tests according to the change in the degree of compaction and water content were performed and it was analyzed with the correlations between the degree of compaction, the void ratio, the degree of saturation and the value of cone resistance. From the laboratory test results, the cone penetration resistance was rapidly increased in the dry side of the optimum moisture content, and it was largely decreased in the wet side of the optimum moisture content. Moreover, when the degree of compaction and the degree of saturation are large, the cone resistance is increased linearly. And a high correlativity was shown between water content, void ratio, the degree of saturation and the cone resistance. From these results, it is judged that the lightweight dynamic cone penetrometer can be applied to the investigation on the site slope.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.545-552
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• 2021

In this study, strength and durability evaluations are performed on vibrated-rolled method mortar mixtures containing desulfurized gypsum and ferronickel slag powder. Desulfurized gypsum and ferronickel slag fine powders were substituted for 25% limestone fine powders u sed in the manu factu re of VR tu bes, and mortar specimens were prepared u sing vibrated-rolled method. Accordingly, flexural and compressive strengths were performed to evaluate the strength, and chlorine ion penetration resistance and sulfuric acid resistance tests were performed to evaluate durability. Flexural and compressive strength were improved in the range 20 to 60% of desu lfu rized gypsu m among admixtu res, and the amou nt of passing charge decreased in the choride ion penetration resistance test in the range of 20 to 80% of desulfurized gypsum. As for the resistance to su lfu ric acid, when the proportion of desu lfu rized in the admixtu re was 40%, the strength and weight change rate according to the immersion period was reduced. Appropriate use of desulfurized gypsum and ferronickel slag powder is expected to improve performance in terms of strength and durability.

• International Journal of Highway Engineering
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• v.7 no.4 s.26
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• pp.113-123
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• 2005

In this study, calcium chloride$(CaCl_2)$, sodium chloride (NaCl), organic acids-containing deicer(NS 40, NS 100), mixed deicier$(NaCl\;70%+CaCl_2\;30%,\;NS\;40\;70%+CaCl_2\;30%,\;NaCl\;70%+NS\;40\;30%,\;NS\;40\;70%+NaCl\;30%)$ is investigated based on the laboratory test for deicing performance, freez-thaw resistance of concrete, and corrosion rate of metal. Test items for deicing performance were ice melting and ice penetration, freezing point depressions and eutectic point, pH, thermal properties for selected deicing chemicals as well as their compatibility with concrete and metal were experimentally investigated. As a test results, in case of the use chloride-containing deicier in area that concrete structures has subjected to freez-thaw reaction in winter season, it showed that mixed deicing chemicals with optimum ratio has desirable method than use one deicing chemicals when is consider to deicing performance and effects, corrosion of steel materials, and freez-thaw resistance of concrete. When use various deicing chemicals mixed, NS40(70%)+calcium chloride(30%) showed the best effective method.

• International Journal of Highway Engineering
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• v.15 no.4
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• pp.107-116
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• 2013

PURPOSES: The liquid-type chemical warm-mix asphalt (WMA) additive has been developed. This study evaluates the basic properties of the additive and the mechanical properties of WMA asphalt and mixture manufactured by using the newly developed chemical additive. METHODS: First, the newly developed WMA additive was applied to the original asphalt by various composition of additive components and dosage ratio of additive. These WMA asphalt binders were evaluated in terms of penetration, softening point, rotational viscosity, and PG grade. Based on the binder test results, one best candidate was chosen to apply to the mixture and then the mechanical properties of WMA mixture were evaluated for moisture susceptibility, dynamic modulus, and rutting and fatigue resistance. RESULTS : According to the binder test, WMA asphalt binders showed the similar properties to the original asphalt binder except the penetraion index of WMA additive was a little higher than original binder. From the Superpave mix design, the optimum asphalt content and volumetric properties of WMA mixture were almost the same with those of hot mix asphalt (HMA) mixture even though the production and compaction temperatures were $30^{\circ}C$ lower for the WMA mixture. From the first set of performance evaluation, it was found that the WMA mixture would have some problem in moisture susceptibility. The additive was modified to improve the resistance to moisture and the second set of performance evaluation showed that the WMA mixture with modified chemical additive would have the similar performance to HMA mixture. CONCLUSIONS : Based on the various laboratory tests, it was concluded that the newly developed chemical WMA additve could be successfully used to produce the WMA mixture with the comparable performance to the HMA mixture. These laboratory evaluations should be confirmed by applying this additive to the field and monitoring the long-term performance of the pavement, which are scheduled in the near future.

• Journal of the Korean Geotechnical Society
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• v.24 no.11
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• pp.71-77
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• 2008

In this study, CPT-based methodology for estimating the ultimate lateral resistance, $p_u$, is proposed and verified for lateral loaded piles in sandy soil. Preexistent methods estimating the ultimate lateral resistance, $p_u$, and the ultimate lateral capacity, $H_u$, of pile have been based on the vertical effective stress, relative density, and the coefficient of lateral earth pressure. Similarly, cone resistance $q_c$ in pure sandy soil is expressed by those essential factors. As correlation between $p_u$ and $q_c$ are normalized with average effective stress ${\sigma}_m$, estimation methodology for the lateral loaded pile of $p_u$ in sandy soil is proposed. The method is verified by calibration chamber test results in pure sand. The standard derivation of estimated $p_u$ is 0.279, and COV (Coefficient Of Variation) of estimated $p_u$ is 0.272. These results showed that the estimated pus by the method are analogous with the measured $p_us$ in calibration chamber test.

• Journal of the Korean Society of Safety
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• v.31 no.4
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• pp.82-89
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• 2016

In this paper, various of experiments were performed for checking the usefulness of Pozzolan Inorganic Polymer(PIP) Waterproof Admixture. The results of the experiment enabled to set the optimum mixture ratio of PIP waterproof admixture as 3.5%. Then, the test specimen mixed with PIP waterproof admixture was produced and consider whether meeting the quality standard of waterproofing admixture for concrete (KS F 4926) From the results, all the items such as mechanical properties and durability were meet the quality standard of KS. The PIP waterproof admixture concrete shows the high resistance of absorption, permeability and chloride ion penetration thanks to its internal components such as siliceous powder, zinc stearate and dispersive polymer.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.443-448
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• 1999

Tests have been carried out on four concrete containing different levels of silica fume to measure their permeability coefficient using water and oxygen, chloride ion. The total cementitious content was 351kg/㎥, and the water/cementitious materials ratio was 0.55. The results show that a dramatic reduction in permeability of concrete containing silica fume occurs due to formation of a discontinuous macro-pore system which inhibits flow. Porosity estimates from mercury-intrusion porosimetry are used to develop an explanations for the water and air permeability reduction. And, results of the rapid permeability test showed that the resistance of concrete to the penetration of chloride ions increases significantly as a contents of silica-fume is increased. The current intensity passing through the concrete containing silica fume is presented from 664C to 2166C.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.269-272
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• 2006

Chloride ion diffusion is the most important thing of occuring deterioration in RC structure. So it is important to decide the precise chloride ion diffusion coefficient in order to predict the durability life in RC structure. The purpose of this study is to analyze the established data, which are restricted by chloride diffusion coefficient, and to calculate chloride ion diffusion coefficient using RCPT test. To examine the prediction of the concrete structure durability by an FEM analysis and the chloride diffusion coefficient as a variable. Each surface finishing materials were effective on the increment of chloride penetration resistance, but showed a little different effect depending on the type of surface finishing material.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.78-81
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• 2003

Recently, physical properties of concrete containing ternary blended cement were actively researching to develop durability, mobility, and atc. as well as strength increase of concrete. In this study, durability of concrete such as the resistance against chloride ion penetration, rebar corrosion, freeze and thaw, and sulfate were researched for concrete containing ordinary portland cement(OPC) and ternary blended cement(TBC), respectively. For this purpose, concrete specimens containing OPC and TBC, respectively, were made for 37.5% of W/C, and then various durability experiments described above were carried out. As a result, it was observed from the test that concrete containing TBC showed excellent durability than concrete containing OPC.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.3-4
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• 2014

There is high probability of steel corrosion on the reinforced concrete exposed to marine environment by penetration of chloride ion. When making concrete structure with slag as admixture in marine environment, salt damage can be prevented. Therefore, this paper presents experimental results of steel corrosion resistance of slag concrete considering marine environment through half-cell potential method which is one of the nondestructive test. As a result of half-cell potential experiment, it was assumed that every specimen exposed to marine environment was not corroded, and as a result of destroying specimens, it was confirmed that there was no corrosion in specimens.