Characterization of Cold-Recycled Asphalt Mixtures : Interim Report (original) (raw)
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IOP conference series, 2018
Older asphalt materials can be recycled using cold, warm, or hot output methods, and the addition of emulsion ingredients, water, and new aggregates to the old asphalt pavement can be completed either in plant or on site. Cold recycling is desirable, but there is little equipment available to processes in-place recycling of this type to enable structural and material problems to be corrected quickly without much disruption to trafficV8For the purposes of assessing the performance of asphalt emulsion recycling mixtures, a cold recycling mix was designed with steps including original material selection, gradation design, adding cement as a filler material, and performance evaluation. Few investigations have been done to assess the tensile and compressive strengths, moisture sensitivity, and rutting of recycled cold mixtures with local materials containing a high percentage of reclaimed asphalt pavement (RAP) of up to 90%. There is thus a need to assess the performance of recycled cold mixtures, especially where they contain high proportions of reclaimed pavement materials that will already have been exposed to local conditions. Recycled cold mixture behaviour has been characterised by its compressive strength, indirect tensile strength, moisture sensitivity, and rut depth. Testing program results showed that cold mixtures containing high percentages of RAP at the end of the various curing periods (1, 7, 14, and 28 days) provided better resistance to permanent deformation, moisture damage, and tensile stresses than a control cold mix with no reclaimed pavement materials. This improved behaviour may be explained by the increase in recycled cold mix stiffness, which offers high RAP and cement bonding with appropriate curing times.
Performance Evaluation of Cold Recycled Asphalt Mixes at Different Temperatures and Loading Rates
Pakistan Journal of Engineering and Applied Sciences, 2016
Nowadays recycling is one of the most advance and interesting technique for the rehabilitation of road pavements. In recent years the increased interest in this process, has led to the development of various alternative methods for the recovery and the reuse of road bituminous materials. Cold recycling allows the recovery of bituminous material from an existing pavement without the addition of heat, whilst ensuring the strength of high quality bound base layers. Resilient behavior, rutting resistance and moisture susceptibility of five different cold recycled asphalt mixes have been investigated using UTM-5P. RAP was used as controlled mix to compare with four other mixes having variable binding material types and percentages. Mixes were evaluated at 40 °C and 50 °C under varying loading conditions of 150 ms and 450 ms. Resilient modulus decreases with increase in type and time of loading for all mixes. Both emulsified bitumen with cement and 100% RAP, and 100% RAP performed excelle...
Cold In-Place Recycling Asphalt Mixtures: Laboratory Performance and Preliminary M-E Design Analysis
Materials, 2021
Cold in-place recycling (CIR) asphalt mixtures are an attractive eco-friendly method for rehabilitating asphalt pavement. However, the on-site CIR asphalt mixture generally has a high air void because of the moisture content during construction, and the moisture susceptibility is vital for estimating the road service life. Therefore, the main purpose of this research is to characterize the effect of moisture on the high-temperature and low-temperature performance of a CIR asphalt mixture to predict CIR pavement distress based on a mechanistic–empirical (M-E) pavement design. Moisture conditioning was simulated by the moisture-induced stress tester (MIST). The moisture susceptibility performance of the CIR asphalt mixture (pre-mist and post-mist) was estimated by a dynamic modulus test and a disk-shaped compact tension (DCT) test. In addition, the standard solvent extraction test was used to obtain the reclaimed asphalt pavement (RAP) and CIR asphalt. Asphalt binder performance, incl...
A Laboratory Investigation of Cold-Mix Recycled Bituminous Pavements : Interim Report
1978
Highway Administration. Part of the Study titled "An Investigation of Recycling Bituminous Pavements". 16. Abitroct In this laboratory study, the effects of different factors on the properties of a cold-recycled asphalt mixture were investigated. The factors investigated were the amount and type of added binder, the amount of added moisture, the added virgin aggregate, the compactive effort and the curing time. A laboratory procedure for preparing and testing cold recycled mixtures was developed and used in the study. Specimens were compacted with the Gyratory machine and tested in the Hveem Stabilometer and Cohesiometer. The Water Sensitivity Test was used to evaluate the resistance of the recycled mixtures to water. The study indicated that the Gyratory machine could be a potentially valuable tool in the evaluation of long time performance of recycled mixtures. The shearing action and the high compactive effort of the gyratory compaction are believed to cause the old and the new binders to act together and thus the long term effect of the rejuvenating action could be detected during compaction. The total effective binder content was found to be the most important factor to the performance of a cold recycled mixture. It was hypothesized that different added virgin binders had different rejuvenating effects on the old binders. The resistance to water depended on the binder content and the type of added binder. A testing procedure for cold-recycled bituminous mixtures was recommended from the findings of this study.
Transportation Research Record: Journal of the Transportation Research Board, 2019
The objective of this paper is to present a procedure for designing cold in-place recycling (CIR) mixtures through balancing rutting and cracking for these mixtures. Four CIR mixtures were prepared using two recycling agents (foamed and emulsified asphalts), and compacted at two gyration levels (30 and 70 gyrations). The CIR mixtures were prepared at a constant water content of 3% and a constant cement content of 1% while curing of the compacted samples was conducted by placing them in an oven for three days at 140°F (dry curing). The CoreLok device was used for measuring air voids in compacted samples. The rutting susceptibility of these mixtures was then evaluated using the asphalt pavement analyzer (APA) and dynamic complex modulus (|E*|) while resistance to cracking was assessed using the indirect tensile strength (ITS) test and fracture energy as determined using the semi-circular bend (SCB-FE) test. A demonstration of how these tests were utilized to select a performance balan...
Performance Evaluation of Asphalt Mixtures with High Recycled Asphalt Pavement Content
Transportation Research Record: Journal of the Transportation Research Board, 2011
This study extensively evaluated the resistance to moisture damage and thermal cracking of hot-mix asphalt (HMA) mixtures with high recycled asphalt pavement (RAP) content (up to 50%) from field sections on provincial Highway 8 between Gimli and Hnausa in Manitoba, Canada. A comparison between the properties and performance of the field-produced and laboratory-produced mixtures was also conducted and was included in this study. HMA mixtures with 50% RAP resulted in acceptable resistance to moisture damage and thermal cracking. The use of multiple freeze–thaw cycles provided a better characterization of the mixtures' resistance to moisture damage. Acceptable correlations were observed between the estimated critical temperatures from the blending chart and the measured ones from the recovered asphalt binders. Overall, laboratory-produced mixtures could be used to evaluate the relative resistance of the field-produced mixtures to moisture damage and thermal cracking.
Laboratory Evaluation of Warm Mix Asphalt and Asphalt Mixtures with Recycled Materials a
Transportation infrastructure poses significant challenges to sustainable development because its construction and maintenance require large amounts of material consumption, energy input, and capital investment. A refined systematic approach to the design, construction, and management of pavement systems is necessary to meet the objectives of sustainable development. The major components of sustainable development in pavement systems include economic and social considerations in addition to environmental preservation. Asphalt mixture design and construction practices are essential to the environmental component of sustainable development. These practices include, but are not limited to, asphaltic mixture reusing and recycling as well as innovative technologies considering energy efficiency and stormwater management. Performance and durability become a critical issue with the changes introduced to the mixtures. This paper briefly summarizes the evaluation of mixture design practices and the performance of asphalt mixtures prepared with various types of recycled materials and warm mix technologies.
Laboratory Evaluation of Warm Mix Asphalt and Asphalt Mixtures with Recycled Materials
2011
Transportation infrastructure poses significant challenges to sustainable development because its construction and maintenance require large amounts of material consumption, energy input, and capital investment. A refined systematic approach to the design, construction, and management of pavement systems is necessary to meet the objectives of sustainable development. The major components of sustainable development in pavement systems include economic and social considerations in addition to environmental preservation. Asphalt mixture design and construction practices are essential to the environmental component of sustainable development. These practices include, but are not limited to, asphaltic mixture reusing and recycling as well as innovative technologies considering energy efficiency and stormwater management. Performance and durability become a critical issue with the changes introduced to the mixtures. This paper briefly summarizes the evaluation of mixture design practices and the performance of asphalt mixtures prepared with various types of recycled materials and warm mix technologies.
2019
The road to sustainability passes through the process of recycling a greater amount of asphalt pavement. Inclusion of additional amounts of reclaimed asphalt pavement (RAP) in new mixes has become a prominent method to promote sustainability. This research addresses some of the challenges related to high RAP content mixes. Among the factors considered are the impact of rejuvenator diffusion on binder stiffness, stiffness gradient, performance grade, homogeneity, and ultimately, their effects on mix performance. In this project, an experiment was conducted to evaluate the effects of the rejuvenator type, dosage rate, and mix-aging protocol on recycled binder homogeneity and mix performance. Another experiment was conducted to evaluate the ability of several simulated aging protocols to produce a binder stiffness and stiffness gradient similar to those observed in natural aging. The results show that the target high temperature grade of a recycled mix should be set at 6 o C higher than that of virgin mixes. In general, mixes with a high temperature grade of 6 o C higher than a virgin mix performed better in rutting and comparably in cracking. There is a strong correlation between binder stiffness gradient and cracking performance. The best simulated aging protocol was to heat the mix to 110 o C for 4 days. These results were based on five mixes and a total of 15 mix/aging protocol combinations.
Performance of a Full-Scale Pavement Using Cold Recycled Asphalt Mixture
Transportation Research Record, 1989
The performance of a full-scale pavement constructed using a cold recycled emulsified asphalt mixture is presented. The cold recycled mixture was used for the surface layer in a trial section of a public road in Israel, subjected to low-volume traffic. The modified Marshall stability method (ASTM D1559) at 60 deg C (140 deg F) was used for the mix design. Experimental field verification was performed starting immediately after construction and lasting 1 yr. The verification included strength and durability tests on cores taken from the site and nondestructive testing (NDT) in situ, based on elastic surface deflection measurements. As shown by the results, the cold recycled apshalt layer achieved high retained strength and high durability potential to the combined damaging effects of water and temperature. After 1 yr of service the pavement has been performing well without any kind of distortion. These findings emphasize the high engineering quality of cold recycled asphalt mixtures ...