• International Journal of Highway Engineering
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• v.19 no.2
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• pp.67-74
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• 2017

PURPOSES : The objective of this study is to ascertain the curing period of cementless cold central plant recycled asphalt base-layer, using mechanical analyses and specimen quality tests on the field. METHODS : Cold central plant recycled asphalt base-layer mixture was produced in the plant from reclaimed asphalt, natural aggregate, filler for the cold mix, and the modified emulsion AP using asphalt mix design and plant mix design. In order to examine the applicability of the curing period during the field test, the international standards for the possibility of core extraction and the degree of compaction and LFWD deflection were analyzed. Moreover, Marshall stability test, porosity test, and indirect tensile strength test were performed on the specimens of asphalt mix and plant mix design. RESULTS : The plant production process and compaction method of cementless cold central plant recycled asphalt base-layer were established, and the applicability of the optical moisture content for producing the mixture was verified through the field test. In addition, it was determined that the core extraction method of the conventional international curing standard was insufficient to ensure performance, and the LFWD test demonstrated that the deflection converges after a two-day curing. However, the back-calculation analysis reveals that a three-day curing is satisfactory, resulting in a general level of performance of dense asphalt base-layer. Moreover, from the result of the specimen quality test of the asphalt mix design and plant mix design according to the curing period, it was determined that the qualities satisfied both domestic and international standards, after a two-day curing. However, it was determined that the strength and stiffness after three-day curing are higher than those after a two-day curing by approximately 3.5 % and 20 %, respectively. CONCLUSIONS:A three-day curing period is proposed for the cementless cold central plant recycled asphalt base-layer; this curing period can be demonstrated to retain the modulus of asphalt-base layer in the field and ensure stable quality characteristics.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.627-634
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• 1997

This is the Study on Application and Manufacture Technique of Cold-Mix, Cold-Laid type Asphalt Concrete using of Polymer modified asphalt the could be constructed easily and economically on damaged road repaireless for seasons. The modified materials for this study are SBS(Styrene-Butadiene-Styrene). SBR (Styrene-Butadiene-Rubber) and PUR(Polyurethane). The Marshall stability and the value of flow and resistance in water stability degree according to the alternation types and weight percent of modified materials were compared and evaluated on this study. The results of the study show that PUR modified asphalt have improvement of over 150% Marshall stability in AI MS-14 standard and they are evaluated to have the easiness of storage and better working efficiency compared with other types of modified asphalt compound.

• International Journal of Highway Engineering
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• v.16 no.4
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• pp.21-33
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• 2014

PURPOSES: The purpose of this study was to break away from the workforce method using cold-mix asphalt mixtures and has a constant quality and has develop repair materials of pre-production asphalt-precast types. METHODS: The selection of the repair material was determined as the results obtained through physical properties of materials and the field applicability. In case of repair materials, values obtained through Marshall stability test & the dynamic stability test & retained stability test as well as the site conditions was considered. In case of adhesive, test results were obtained through examination of the bond strength(tensile, shear) and the field applicability of the adhesive was examined through combined specimens to simulate field applications. RESULTS : According to the results of laboratory tests, in the case of repair materials, Marshall stability and dynamic stability, retained stability of cold-mix reaction type asphalt mixture is the highest. In the case of adhesive, two-component epoxy-urea has a very high bonding strength(tensile, shear) was most excellent. According to the results of field tests, when epoxy-urea was excellent workability. Also, the repair body through actual mock-up test did not occur large deformation and fracture after 12 months. CONCLUSIONS : A suitable repair material is cold-mix reaction type mixture of asphalt-precast, a suitable adhesive is a two-component epoxy-urea.

• International Journal of Highway Engineering
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• v.19 no.2
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• pp.75-85
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• 2017

PURPOSES : The purpose of this study was to determine the optimum mix design of the content of 100 % reclaimed asphalt pavement (RAP) for spray injection application with different binder types. METHODS : Literature review revealed that spray injection method is the one of the efficient and economical methods for repairing a small defective area on an asphalt pavement. The Rapid-Setting Polymer modified asphalt mixtures using two types of rapid setting polymers-asphalt emulsion and a quick setting polymer asphalt emulsion-were subjected to the following tests to determine optimum mix designs and for performance comparison: 1) Marshall stability test, 2) Retained stability test, 3) Wet track abrasion test, and 4) Dynamic stability test. RESULTS and CONCLUSIONS : Type A, B, and C emulsions were tested with different mix designs using RAP aggregates, to compare the performances and determine the optimum mix design. Performance of mixtures with Type A emulsion exceeded that of mixtures with Type B and C emulsion in all aspects. In particular, Type A binder demonstrated the highest performance for WTAT at low temperature. It demonstrated the practicality of using Type A mixture during the cold season. Furthers studies are to be performed to verify the optimum mix design for machine application. Differences in optimum mix designs for machine application and lab application will be corrected through field tests.

• Journal of Soil and Groundwater Environment
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• v.9 no.4
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• pp.24-31
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• 2004

A cold mix asphalt (CMA) treatment process was proposed as a tool to recycle soils contaminated with petroleum hydrocarbons. Experimental studies were conducted to characterize performances of the CMA process in treating soils contaminated with diesel or diesel compounds. From the screening experiments, it was found that performances of five types of asphalt emulsions that contained a cationic or an anionic or a nonionic surfactant were not substantially different. In consideration of higher affinity for soils and higher sorption coefficients obtained, an emulsion containing Lauryl Dimethyl Benzyl Ammonium Chloride (LDBAC) was selected as a promising asphalt emulsion for treating diesel-contaminated soils. When the asphalt emulsion LDBAC was applied to treat three compounds that originated from diesel, the removal efficiencies obtained in the order of decreasing efficiencies were as follows: docosane > pentadecane > undecane. Leaching experiments on the specimen formulated by the emulsion LDBAC found that the selected treatment method could treat soils with diesel concentrations as high as 10,000 mg/kg. Leaching of the diesel from the specimen was controlled by diffusion for the first four days and then leaching rate diminished substantially. The latter behavior was characterized as depletion, which represents that the contaminant released amounts to more than $50\%$ of the total amount of the contaminant that can be leached. The amounts of three diesel compounds leached from the specimen in the order of decreasing amount were undecane, pentadecane, and docosane. The curing of the soil contaminated with pentadecane was relatively slow.

• Magazine of RCR
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• v.17 no.3
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• pp.18-24
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• 2022

• International Journal of Highway Engineering
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• v.20 no.1
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• pp.47-58
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• 2018

PURPOSES : The purpose of this study is to evaluate the mechanical properties of a cold-recycling asphalt mixture used as a base layer and to determine the optimum emulsified-asphalt content for ensuring the mixture's performance. METHODS : The physical properties (storage stability, mixability, and workability) of three types of asphalt emulsion (CMS-1h, CSS-1h, and CSS-1hp) were evaluated using the rotational viscosity test. Asphalt emulsion residues, prepared according to the ASTM D 7497-09 standard, were evaluated for their rheological properties, including the $G*/sin{\delta}$and the dynamic shear modulus (${\mid}G*{\mid}$). In addition, the Marshall stability, indirect tensile strength, and tensile-strength ratio (TSR) were evaluated for the cold-recycling asphalt mixtures fabricated according to the type and contents of the emulsified asphalt. RESULTS : The CSS-1hp was found to be superior to the other two types in terms of storage stability, mixability, and workability, and its $G*/sin{\delta}$ value at high temperatures was higher than that of the other two types. From the dynamic shear modulus test, the CSS-1hp was also found to be superior to the other two types, with respect to low-temperature cracking and rutting resistance. The mixture test indicated that the indirect tensile strength and TSR increased with the increasing emulsified-asphalt content. However, the mixtures with one-percent emulsified-asphalt content did not meet the national specification in terms of the aggregate coverage (over 50%) and the indirect tensile strength (more than 0.4 MPa). CONCLUSIONS : The emulsified-asphalt performance varied greatly, depending on the type of base material and modifying additives; therefore, it is considered that this will have a great effect on the performance of the cold-recycling asphalt pavement. As the emulsified-asphalt content increased, the strength change was significant. Therefore, it is desirable to apply the strength properties as a factor for determining the optimum emulsified-asphalt content in the mix design. The 1% emulsified-asphalt content did not satisfy the strength and aggregate coverage criteria suggested by national standards. Therefore, the minimum emulsified-asphalt content should be specified to secure the performance.

• 한국도로학회:학술대회논문집
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• 2008.10a
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• pp.251-257
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• 2008

• International Journal of Highway Engineering
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• v.18 no.2
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• pp.61-71
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• 2016

PURPOSES: The objective of this study was to determine the optimum ratio of mix design, for a reclaimed asphalt pavement (RAP) content of 100%, for spray injection application. METHODS: A literature review revealed that spray injection is an efficient and cost-effective application for fixing small defective regions of an asphalt pavement. Rapid-setting polymer-modified asphalt mixtures prepared from two types of rapid-setting polymer asphalt emulsion were subjected to Marshall stability and wet track abrasion tests, in order to identify the optimum mix designs. RESULTS and CONCLUSIONS : Different mix designs of type A and type B emulsions were prepared using RAP and virgin aggregates, in order to compare the performance and determine the optimum mix design. The performance of mixtures prepared with RAP was superior to that of mixtures containing virgin aggregates. Moreover, for optimum ratio of the design, the binder content prepared from RAP was set to 1~2% lower than that consisting of virgin aggregates. Compared to their Type A counterparts, type B mixtures consisting of a reactive emulsion performed better in the Marshall stability and wet track abrasion tests. The initial results confirmed the advantages associated with using RAP for spray injection applications. Further studies will be performed to verify the difference in the optimum mix design and performance obtained in the lab-scale test and tests conducted at the job site by using the spray injection machine.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.313-316
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• 2008

Temperature reduction in the manufacturing of asphalt mixtures is highly desirable from a number of aspects. Reduced fumes and emissions, and reduced energy consumption, are important environmental reasons to continue pursuing the goal of temperature reduction. There are important construction and performance advantages as well. For instance, improved workability results in better compaction; lower production and placement temperatures may improve prospects for cold weather paving; and lower temperatures will result in less binder aging and possibly better cracking resistance. The performance of WMA is not to be satisfied though there are various advantages. Therefore, more research is needed on a number of issues