• Research Article

    A study of watertight asphalt mixture for the asphalt overlay on concrete pavement

    콘크리트 포장 덧씌우기를 위한 하부층용 수밀성 아스팔트 혼합물에 관한 연구

    Kyung-Ha Lee

    이경하

    In ths study, the characteristics of watertight asphalt concrete were analyzed to prolong the life of overlay over concrete pavement. It was ... + READ MORE
    In ths study, the characteristics of watertight asphalt concrete were analyzed to prolong the life of overlay over concrete pavement. It was shown that the air void content was grater than or equal to 1.0 percentage (%) in order to meet the minimum standard for dynamic stability. And the range to secure a stable dynamic stability level of 1,000 cycle/mm was found to be between 1.0 and 2.0%. Under the same dynamic stability level condition, it was possible to reduce air void content by 1.0% by using PG 76-22 binder compared with using to PG 64-22 binder. This will be a great advantage for the asphalt layer to provide more stable watertightness under the surface course. The APT test results showed that the average rut depth of watertight WC-1 (PG 64-22) was 3.1 mm and 1,5 times higher than watertight WC-1 (PG 76-22). When the dynamic stability was increased by 5.8 times, the rut depth of APT test tends to decrease by 1.5 times. The results of the follow-up investigation of the test construction showed that watertight WC-1 (PG 64-22) with was 4.5mm in rut depth, which is 1.2 times higher in depth than watertight WC-1 (PG 76-22). - COLLAPSE
    June 2019
  • Research Article

    Installation and implementation of proper tack coat application
    Mithil Mazumder, Moon-Sup Lee, Soon-Jae Lee
    Tack coat is a form of bituminous emulsion placed between two bituminous layers, so that the two layers can act as a ... + READ MORE
    Tack coat is a form of bituminous emulsion placed between two bituminous layers, so that the two layers can act as a single monolithic unit to sustain the traffic loads. Several studies have been conducted on evaluating the proper tack coat application to ensure superior shear strength. The objective of this paper is to synthesize existing literature, research projects and agency specifications regarding the practice of tack coat application. Proper tack coat application depends on several factors such as tack coat type, application rate and its coverage, temperature, storage condition, pavement surface texture and condition, cleanliness of the surface, asphalt distributor and its consistency, curing or setting time, quality of compaction, and so on. Overall, it contains a comprehensive review of all the known literatures and documents a synthesis study on all those factors impacting the performance of tack coat. - COLLAPSE
    June 2019
  • Research Article

    Relaxation modulus computation of asphalt mixture using simple power law model with IDT (In-Direct Tensile) testing equipment
    Ki-Hoon Moon, Oh Sun Kwon, Sung Jin Lee, Augusto Cannone Falchetto
    Low temperature cracking is one of the crucial distresses on asphalt pavement especially for Northern U.S., Canada and Korea. Normally, this ... + READ MORE
    Low temperature cracking is one of the crucial distresses on asphalt pavement especially for Northern U.S., Canada and Korea. Normally, this crack pattern presents transverse shape and makes water infiltration into pavement layer easily. Finally, serious distresses such as reveling, pop-out and pot-hole issues emerge which provides negative performances on existing asphalt pavement. It is well known that thermal stress can be computed numerically based on relaxation modulus of asphalt mixture by means of low temperature creep test. However, the inter-conversion approach between creep compliance and relaxation modulus is rather complicated therefore, only few research agencies can compute relaxation modulus and thermal stress of given asphalt materials. In this paper, a simple relaxation modulus computation approach using power law function is introduced. By using this computation approach, it is expected that more pavement research and managing agencies can easily generate relaxation modulus of given asphalt materials (binder and mixture) from creep testing. - COLLAPSE
    June 2019
  • Research Article

    Investigation of binder aging level in short-term-aged PMA mixture with different anti-stripping additives
    Sungun Kim, Yeongsam Kim, Wonbae Kim, Kwang Woo Kim4
    As an anti-stripping additive (ASA) of hot-mix asphalt (HMA) mixture, the hydrated lime (HL) has been widely used for many years. Conversely ... + READ MORE
    As an anti-stripping additive (ASA) of hot-mix asphalt (HMA) mixture, the hydrated lime (HL) has been widely used for many years. Conversely, many brands of liquid anti-stripping additive (LA), which properly provide the anti-stripping function, are also used. HL is known to provide anti-aging functions by retarding age-hardening of the binder in addition to ASA functions. However, the LA was not much evaluated or reported regarding anti-aging function. Since the retardation of binder age-hardening is the foundation of many other beneficial functions of asphalt pavements, it is important to investigate whether the anti-aging function is provided by the LA as well. Therefore, this study investigated the anti-aging effects of HL and two liquid additives in SBS-modified SMA mixes in terms of absolute viscosity estimated from large molecular size (LMS) measured by the gel-permeation chromatography (GPC). It was found that two LAs did not provide any retardation of age hardening effects in polymer-modified asphalt mixes, compared with the binder of the mixes with HL and without any ASA. The PMA in one of the LAs showed a significantly higher age-hardening than the one without any ASA. While HL reacted as a significant age-hardening retarder of PMA in SMA mixes. Therefore, it was concluded that there was significant difference in oxidation level due to the use of different ASAs used in this study. - COLLAPSE
    June 2019
  • Research Article

    Development of budget forecasting procedure for local road asphalt pavement maintenance using LrPCI

    지역도로 아스팔트포장 평가지수를 이용한 유지보수 소요예산 예측절차 개발

    Junseong Choi, Joowon Seo

    최준성, 서주원

    Due to the nature of the Municipal and local road asphalt pavement, the evaluation procedure and the maintenance budget estimation procedure in ... + READ MORE
    Due to the nature of the Municipal and local road asphalt pavement, the evaluation procedure and the maintenance budget estimation procedure in the excessive crack and the excessive rutting section are indispensable. In this study, we propose Maintenance selection procedure suitable for local roads using modified local pavement condition index (modified LrPCI) which can evaluate the present state of asphalt pavement according to road grade, traffic volume and importance of local roads. We have developed an algorithm that can predict the maintenance budget for repairing by the proposed procedures. According to the maintenance estimation procedure proposed in this study, it is possible to obtain the average LrPCI correlation with the repair cost of the local road asphalt pavement. From this correlation, it is possible to calculate the approximate scale of the maintenance cost required for the quantitative performance management through the road management system of the local roads. Therefore, the developed algorithm can be used as a basis for estimating the appropriateness of the local government budget and can be used by local governments to forecast maintenance costs to manage local road asphalt pavement on a goal management basis. - COLLAPSE
    June 2019
  • Research Article

    Properties of asphalt mixtures for base layer using waste glass fine aggregate

    폐유리 잔골재를 사용한 기층용 아스팔트 혼합물 특성

    Youngjin Jo, Sangchul Lee, Kwangwoo Kim, Sungun Kim

    조영진, 이상철, 김광우, 김성운

    Waste glass bottles are usually reused as glass bottles again after screening, cleaning and/or crushing and melting for recycling purpose. The ... + READ MORE
    Waste glass bottles are usually reused as glass bottles again after screening, cleaning and/or crushing and melting for recycling purpose. The glass aggregate (GFA) can be used in replace of natural fine aggregate (NFA) as construction material like as production of asphalt mixtures. In USA and Europe, the GFA, which was produced from crushed waste glass bottles, have been used for making asphalt mixtures under the name of the Glassphalt. Recently, Korea Circulation Resource Distribution Center and Construction & Transportation Business Division conducted a study to replace 50% of NFA with GFA to produce asphalt mixture. In this study, the performance test of the GFA asphalt mixture to apply for the base course was carried out. Deformation strength (SD) was performed to evaluate the rutting resistance. The moisture sensitivity was evaluated by the deformation strength ratio (SDR) test and tensile strength ratio (TSR), and the indirect tensile strength (ITS) was measured to evaluate the crack resistance. As are results, SD and ITS of GFA asphalt mixture for base layer showed similar to the normal hot-mix asphalt (HMA) mixture. SDR was also similar to HMA. The mixture containing the GFA showed similar properties for rutting resistance, crack resistance, and moisture susceptibility as compared to normal HMA, and was satisfied the criterion of base layer specifications. However, It is consider that the absorption rate of GFA is closed to zero, so that the asphalt cannot be absorbed to the GFA during the production of the asphalt mixture. This is the source of low bonding strength of the mixture, resulting in reduced stripping and rutting resistances. Therefore it was judged that additional measure should be taken to use the GFA asphalt mixture in surface layer. - COLLAPSE
    June 2019
  • Technical Notes

    Technical report on 100% hot-in-place asphalt recycling trial pavement
    Sangil Hong, Jongwoo Jang, Jaemin Seo, Sangmin Kim
    This technical report summarizes the results of the trial pavement of 100% Hot In Place Asphalt Recycling (HIPER) for the first time ... + READ MORE
    This technical report summarizes the results of the trial pavement of 100% Hot In Place Asphalt Recycling (HIPER) for the first time in Korea. Through the trial pavement, the analysis of existing pavement samples, development of mixing design method, performance of new equipment system and characteristics of recycled mixture were checked. As a result of the pavement, it was confirmed that there was little change in the aggregates gradation before and after the application, and it was confirmed that 100% RAP recycling is possible without the need of inputting the new asphalt mixture for gradation correction. Also, the bonding between the lower layer and the recovered layer was excellent and the longitudinal joint treatment was also excellent. However, due to the inexperience of the equipment operator, the pre-heating showed a large variation in temperature in certain sections and regions. It will be necessary to supplement this and to have skilled workers. - COLLAPSE
    June 2019