포장용 롤러전압콘크리트의 다짐도와 압축강도의 상관관계 분석

정건우,송시훈,이승우 대한토목학회 2016 대한토목학회논문집 Vol.36 No.6

Roller-Compacted Concrete Pavement (RCCP) is a type of pavement that shares conventional concrete pavement material characteristics and asphalt pavement construction characteristics. Even though RCCP is compacted in the same way and have similar aggregate gradation to asphalt pavements, its materials and structural performance properties are similar to those of conventional concrete pavement. With cement hydration and aggregate interlock, Roller-Compacted Concrete or RCC can provide strength properties equal to those of conventional concrete with low cement content. Therefore, compaction ratio of RCC can highly influence on its strength. In general, 95% of compaction ratio is required for proper strength development. RCC strength can be highly influenced by compaction energy which depends on compaction equipment and compaction method. Therefore, it is necessary to analyze the relationship between compressive strength and compaction ratio of RCC. RCCP specimens were produced at different compaction ratio by using different compaction methods and energies. The compaction ratio was defined by the ratio of the specimen's dry density and its maximum dry density. The maximum dry density was obtained from Modified Proctor test. 28 days compressive strength corresponding to each compaction ratio case was tested. Finally, the relationship between compressive strength and compaction ratio can be analyzed. For application of roller-compacted concrete in domestic construction site, the relationship is important for field compaction management. 롤러전압콘크리트포장 공법은 기존 시멘트 콘크리트 공법의 재료 특성 및 아스팔트 포장의 시공특성을 공유하는 포장 방식이다. 일반 시멘트 콘크리트 포장의 우수한 구조적 성능을 유지하면서, 아스팔트 시공 장비를 사용하여 간소한 시공절차로 경제성을 확보할 수 있다. 롤러전압콘크리트포장 공법은 수화반응과 롤러다짐에 의한 골재 맞물림 효과로 일반 시멘트 콘크리트 포장보다 적은 시멘트량을 사용하여도 충분한 강도를 발현할 수 있다. 또한 일반 시멘트 콘크리트 포장과 동등한 강도 특성을 발휘 할 수 있으며, 본 연구에서는 RCCP의 다짐도와 압축강도의 관계를 정량적으로 도출하고자 한다. 롤러전압콘크리트의 다짐에너지를 변화시키면서 다양한 다짐도를 갖는 시편을 제작하였다. 다짐도는 시편의 건조단위중량과 최대건조단위중량의 비로 정의하였으며, 다양한 다짐도로 성형된 시편의 28일 압축강도를 평가하였고, 다짐도에 따른 강도비의 관계를 도출 하였다. 따라서 롤러전압콘크리트 공법의 국내 현장적용을 위한 다짐도에 따른 강도비의 중요성을 부각하여 현장 다짐도 관리에 적용할 수 있을 것으로 판단된다.

Evaluation of Effectiveness of Roller Compacted Concrete Pavement by Improving Roughness

Jun Young Park,Hye Min Jeong,Jin Cheol Kim,Sung Woo Ryu 한국도로학회 2018 한국도로학회 학술대회 발표논문 초록집 Vol.2018 No.05

Roller Compacted Concrete Pavement (RCCP) is a pavement placed and compacted using an asphalt paver and a compaction roller by applying a small amount of concrete mixture and shows excellent structural performance as a result of hydration reaction of cement and interlocking of aggregates by roller compaction. It also provides economic advantages over conventional concrete pavements by reducing unit cement content and construction period, simplifying construction process, and decreasing traffic closure time (Wayne, 2006). However, given that it tends to show lower IRI levels than common concrete pavements since its low unit water content and binder weight ratios make uniform quality control difficult and roller compaction after paving makes the surface irregular and rough, with rough profile at the bottom of the pavement being reflected on the surface, RCCP is used mainly in port and industrial roads for low speed (60km/h or less) traffic (Dale Harringtion, 2010; Gregory, 2009). In order to apply RCCP to high-speed roadways, diamond grinding (DG) or asphalt overlay that is highly effective in improving roughness is needed (Fares Abdo, 2014; Gregory, 2009). Applying DG over RCCP leads to excellent skid resistance and noise reduction effects as a great percentage of aggregates makes the pavement surface rough, enhancing durability of concrete and the life of DG functionality. In addition, RCCP can be used as a high performance base layer of composite pavements, as it can reduce reflecting cracking at joints and cracked sections thanks to early strength development and low drying shrinkage of concrete. In this study, we assessed longitudinal roughness improvement effects by roughness-affecting factor by applying DG methods and asphalt overlays to three RCCP sites with a variety of sub-structural conditions and analyzed the effects on roughness of existing RCC pavements depending on surfacing method (DG, APOverlay).

친환경 자전거도로를 위한 롤러 다짐 콘크리트 포장의 기초물성에 관한 연구

이창호,강재규,박철우,이승우 한국도로학회 2010 한국도로학회논문집 Vol.12 No.3

Recently, usage bicycle has been encouraged to reduce energy consumption and CO2. For this purpose, lots of bike road construction are planned. Typical type of pavement used in bikeroad such as asphalt concrete pavement, portland cement concrete pavement, colored pavement, soil pavement. However, these pavement types may need high construction cost comparing the required capacity of bike road. In this study, roller compacted concrete pavement which are economical and durable, are investigated to use as bike road pavement. The optimum compaction level and mix design of roller compacted concrete pavement are suggested by exploring strength test with various mixture ratio and compaction level, Also durability was examined based on freeze-thaw and scaling test. In addition, the cost and amount of carbon emission during in the construction of roller compacted concrete were evaluated and compare with the cost and carbon emission of typical portland cement concrete. 에너지 절약과 CO2발생량의 절감을 위해 자전거의 이용을 적극 장려하고 있다. 이를 위해 다량의 신설 자전거 도로 건설 계획을 추진 중에 있다. 현재 국내에서 신설 자전거도로 건설을 위해 아스팔트포장 및 콘크리트 포장을 비롯하여, 반강성포장, 유색포장, 흙포장 등이 적용되고 있다. 하지만 이들 포장형식은 자전거도로의 요구 성능에 비하여 시공비용이 높다. 본 연구에서는 경제적이고 친환경적이며 내구성을 확보한 자전거도로포장으로써 롤러 다짐 콘크리트의 최적 다짐율과 배합비를 기초물성시험을 통해 검토하였다. 도출된 배합비에 대한 동결융해와 제설제 저항성 시험을 통해 환경저항성을 검토하였다. 추가적으로 경제성 및 CO2발생량을 일반콘크리트포장과 비교를 통해 평가했다.

A study on investigating the properties of alkali-activated roller compacted concretes

Kilic, Ismail,Gok, Saadet Gokce Techno-Press 2021 Advances in concrete construction Vol.12 No.2

In this study, it was aimed to contribute to a more environmentally friendly concrete production by using alternative binders, which are waste or by-products that can be used instead of cement. For this purpose, alkali-activated materials were used, a cleaner production process was supported by reducing the amount of activator, a different production method was preferred to prevent the workability problem caused by dry consistency, and roller compacted concrete was produced. Ground granulated blast furnace slag (GGBFS) and fly ash were used as precursors, and an activator solution prepared by mixing 10 M sodium hydroxide (NaOH) and sodium silicate (Na₂SiO₃), which has a Na₂SiO₃/NaOH ratio of 2.5, was used in production of alkali-activated roller compacted concretes. Also, Portland cement roller compacted concrete was produced with the same dosage for comparison purposes. Unit weight, total water absorption, ultrasonic pulse velocity (UPV), modulus of elasticity, abrasion resistance, 7 and 28-d compressive strength values of the alkali-activated RCCs were determined. While the roller compacted concretes produced with fly ash were weaker than Portland cement RCCs in terms of compressive strength, the specimens produced using blast furnace slag have been found to be superior.

롤러 전압 콘크리트 포장의 공기량 및 기포간격계수와 장기 내구성의 상관관계 분석을 위한 실험적 연구

이준희,이승우 한국도로학회 2016 한국도로학회논문집 Vol.18 No.1

PURPOSES : The use of roller-compacted concrete pavement (RCCP) is an environmentally friendly method of construction that utilizes the aggregate interlock effect by means of a hydration reaction and roller compacting, demonstrating a superb structural performance with a relatively small unit water content and unit cement content. However, even if an excellent structural performance was secured through a previous study, the verification research on the environmental load and long-term durability was conducted under unsatisfactory conditions. In order to secure longterm durability, the construction of an appropriate internal air-void structure is required. In this study, a method of improving the long-term durability of RCCP will be suggested by analyzing the internal air-void structure and relevant durability of roller-compacted concrete. METHODS: The method of improving the long-term durability involves measurements of the air content, air voids, and air-spacing factor in RCCP that experiences a change in terms of the kind of air-entraining agent and chemical admixture proportions. This test should be conducted on the basis of test criteria such as ASTM C 457, 672, and KS F 2456. RESULTS : Freezing, thawing, and scaling resistance tests of roller compacted concrete without a chemical admixture showed that it was weak. However, as a result of conducting air entraining (AE) with an AE agent, a large amount of air was distributed with a range of 2~3%, and an air void spacing factor ranging from 200 to 300 ㎛ (close to 250 ㎛) coming from PCA was secured. Accordingly, the freezing and thawing resistance was improved, with a relative dynamic elastic modulus of more than 80%, and the scaling resistance was improved under the appropriate AE agent content rate. CONCLUSIONS: The long-term durability of RCCP has a direct relationship with the air-void spacing factor, and it can be secured only by ensuring the air void spacing factor through air entraining with the inclusion of an AE agent.

롤러전압콘크리트 기층의 누적피로손상을 고려한 중하중 도로의 복합포장 두께 설계

김경수,김영규,차이리후워,이승우 대한토목학회 2022 대한토목학회논문집 Vol.42 No.4

It is important to design the pavement thickness considering heavy-duty traffic loads, which can cause excessive stress and strain in the pavement. Port-rear roads and industrial roads have many problems due to early stress in pavement because these have a higher ratio of heavy loads than general roads such as national roads and expressways. Internationally, composite pavement has been widely applied in pavement designs in heavy-duty areas. Composite pavement is established as an economic pavement type that can increase the design life by nearly double compared to that of existing pavement while also decreasing maintenance and user costs. This study suggests a thickness design method for composite pavement using roller-compacted concrete as a base material to ensure long-term serviceability in heavy-duty areas such as port-rear roads and industrial roads. A three-dimensional finite element analysis was conducted to investigate the mechanical behavior and the long-term pavement performance ultimately to suggest a thickness design method that considers changes in the material properties of the roller-compacted concrete (RCC) base layer. In addition, this study presents a user-friendly catalog design method for RCC-base composite pavement considering the concept of linear damage accumulation for each container trailer depending on the season. 중하중의 교통하중은 포장체에 과도한 응력과 변형을 발생시키므로 이에 대응할 수 있는 포장 단면 설계가 중요하다. 항만 배후도로와 산업도로는 일반도로에 비해 중하중 교통의 비율이 높아 포장의 조기 파손으로 인한 문제가 다수 발생되고 있다. 국외의 경우 중차량의 통행이 많은 도로의 포장설계는 복합포장을 많이 적용하고 있다. 복합포장은 기존 포장의 설계수명을 2배 이상 증대시켜 보수비용 및 사용자 비용을 절감할 수 있는 경제적 포장 형식으로 인식되고 있다. 본 연구에서는 중하중 교통의 비율이 높은 산업도로와 항만 배후도로의 포장 장기 공용성을 확보할 수 있도록 롤러전압콘크리트 기층을 활용한 복합포장의 두께 설계 방안을 제안하고자 한다. 3차원 유한요소해석을 이용하여 포장의 재료물성 변화에 따른 역학적 거동과 장기 공용성을 검토하였으며, 계절별 컨테이너 트레일러에 의해 발생되는 롤러전압콘크리트 기층의 누적피로손상도을 고려하여 사용자가 쉽게 사용할 수 있는 카탈로그 설계를 제안하였다.

Workability Improvement of Roller-Compacted Concrete Pavement

Chhorn Chamroeun,Han Seung Hwan,Chon Beom Jun,Lee Seung Woo 한국도로학회 2016 한국도로학회 학술발표회 논문집 Vol.2016 No.06

Roller-compacted concrete or RCC is a dry concrete that requires compaction in order to reach its final form. Its consistency is usually overlooked due to its inconsistency and lack of subjective nature. To work with this concrete, however, appropriate consistency is required for supporting the compacting machine and minimizing compaction energy. Due to transportation and compaction time, maintaining proper consistency within a period of time is also necessary. Vebe time, a represent parameter of dry concrete consistency, ranged from 30 to 75 seconds is considered appropriate for RCC in pavement application. The purpose of this study is to improve workability of this concrete which consisted of improving its consistency and maintaining it within the working time. It was confirmed that the workable time of a normal RCC is less than one hour. Moreover, it was found that Vebe time drops when water content increases and goes up when sand by aggregate ratio increases. Various admixtures were also employed in this study in order to improve the workability of this concrete. Poly Naphtalene Sulfonate superplasticizer, particularly, was found to be the most effective in term of lowering down Vebe time and maintaining it. With just 0.3% of this admixture, the working time of RCC can be extended up to four hours without affecting its compressive strength.

Relationship between flexural or splitting tensile strength and compressive strength of roller-compacted concrete

Chhorn Chamroeun,Han Seung Hwan,Chon Beom Jun,Lee Seung Woo 한국도로학회 2015 한국도로학회 학술발표회 논문집 Vol.2015 No.10

More Roller-compacted concrete (RCC) is a dry concrete consisted of same materials as conventional concrete with different proportioning which requires compaction effort in order to reach its final form. Thus, both hydration and aggregate interlock play important roles in its strength augmentation. Flexural strength, an important factor in pavement design and fatigue cracking resistance, can be difficult to be obtained at in-situ and may be subjected to high variability. Even though its compressive strength is relatively high compared to conventional concrete with similar binder content, the relationship between compressive strength and flexural or tensile strength were not well defined. The goal of this research is to compare the relationship between compressive strength and flexural strength as well as the relationship between compressive strength and splitting tensile strength of RCC with those of conventional concrete using various equations suggested in other researches and also to determine new regression equations for estimating RCC’s flexural and splitting tensile strength. The positive result of RCC’s flexural strength was found; it was higher than majority of predicted values from conventional concrete for the same compressive strength. In contrast, RCC’s splitting tensile strength was relatively low compared to that of conventional concrete for the same compressive strength. Power equations were learned to be suitable for relationship between compressive and flexural strengths as well as relationship between compressive and splitting tensile strengths.

A study on performance of roller-compacted concrete for pavement

Chhorn, Chamroeun,Hong, Seong Jae,Lee, Seung-Woo Elsevier 2017 Construction and Building Materials Vol.153 No.-

<P><B>Abstract</B></P> <P>In this study, field test investigation is conducted on roller-compacted concrete pavement (RCCP). A total of five sections of RCCP were constructed in Seokcho of South Korea for this test. Vebe time, a represented parameter of consistency, is employed as quality control parameter for RCC mixture. Performance related properties and surface properties of each section were investigated and correlated to the quality control parameter. Based on the findings from previous researches and results from this field performance investigation, some recommendations for improving mixture design of RCC are suggested.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The performance of roller-compacted concrete pavement (RCCP) is investigated. </LI> <LI> The evaluation of mixture design of RCCP is conducted. </LI> <LI> Recommended range of consistency is suggested for RCCP. </LI> </UL> </P>

롤러다짐 댐 콘크리트의 효율적인 배합비 도출에 관한 연구

원종필,윤종환,김완영,Won, Jong-Pil,Yoon, Jong-Hwan,Kim, Wan-Young 한국농공학회 2004 한국농공학회논문집 Vol.46 No.1

Roller-compacted concrete(RCC) dam have gained acceptance worldwide in a relatively short time due to their low cost, which is derived in part from their rapid method of construction. And RCC has recently emerged as an economically attractive material for dam construction, replacing the use of conventional concrete and even challenging the economics of earthfill and rockfill embankment dams. There are existing two major mix design methods. one used in USA and the other used in Japan. In this study, proper mix proportions of concrete for RCC dam is obtained using method of compound their merit.