Laboratory Study on Cold-Mixtures for Asphalt Pavement

2012 ◽  
Vol 178-181 ◽  
pp. 1361-1364
Author(s):  
Shi Bin Ma ◽  
Li Jie Wang ◽  
Guo Qiang Zhang

The main purpose of recycling is to reuse existing pavement material. First this paper reviews the necessary, feasibility and mechanistic analysis of recycled asphalt mixture, then summarizes the findings of a laboratory study to characterize and design recycled asphalt concrete mixtures using different tests. The laboratory tests carried out on the material were conventional test methods including unconfined compressive strength, cleavage strength, resilient modulus and shrinkage properties tests. The results of the laboratory can be taken as reference in design, engineering and further research.

2019 ◽  
Vol 15 (1) ◽  
pp. 206-226 ◽  
Author(s):  
Kabiru Abdullahi Ahmad ◽  
Norhidayah Abdul Hassan ◽  
Mohd Ezree Abdullah ◽  
Munder A.M. Bilema ◽  
Nura Usman ◽  
...  

Purpose In order to fully understand the properties of porous asphalt, investigation should be conducted from different point of views. This is from the fact that porous asphalt mixture designed with the same aggregate gradation and air void content can give different infiltration rate due to the different formation of the internal structure. Therefore, the purpose of this paper is to investigate the micro-structural properties and functional performance of porous asphalt simultaneously. Design/methodology/approach The aim is to develop imaging techniques to process and analyze the internal structure of porous asphalt mixture. A few parameters were established to analyze the air void properties and aggregate interlock within the gyratory compacted samples captured using a non-destructive scanning technique of X-ray computed tomography (CT) throughout the samples. The results were then compared with the functional performance in terms of permeability. Four aggregate gradations used in different countries, i.e. Malaysia, Australia, the USA and Singapore. The samples were tested for resilient modulus and permeability. Quantitative analysis of the microstructure was used to establish the relationships between the air void properties and aggregate interlock and the resilient modulus and permeability. Findings Based on the results, it was found that the micro-structural properties investigated have successfully described the internal structure formation and they reflect the results of resilient modulus and permeability. In addition, the imaging technique which includes the image processing and image analysis for internal structure quantification seems to be very useful and perform well with the X-ray CT images based on the reliable results obtained from the analysis. Research limitations/implications In this study, attention was limited to the study of internal structure of porous asphalt samples prepared in the laboratory using X-ray CT but can also be used to assess the quality of finished asphalt pavements by taking core samples for quantitative and qualitative analysis. The use of CT for material characterization presents a lot of possibilities in the future of asphalt concrete mix design. Originality/value Based on the validation process which includes comparisons between the values obtained from the image analysis and those from the performance test and it was found that the developed procedure satisfactorily assesses the air voids distribution and the aggregate interlock for this reason, it can be used.


2021 ◽  
Vol 16 (2) ◽  
pp. 48-65
Author(s):  
Audrius Vaitkus ◽  
Judita Gražulytė ◽  
Andrius Baltrušaitis ◽  
Jurgita Židanavičiūtė ◽  
Donatas Čygas

Properly designed and maintained asphalt pavements operate for ten to twenty-five years and have to be rehabilitated after that period. Cold in-place recycling has priority over all other rehabilitation methods since it is done without preheating and transportation of reclaimed asphalt pavement. Multiple researches on the performance of cold recycled mixtures have been done; however, it is unclear how the entire pavement structure (cold recycled asphalt pavement overlaid with asphalt mixture) performs depending on binding agents. The main objective of this research was to evaluate the performance of cold in-place recycled asphalt pavements considering binding agents (foamed bitumen in combination with cement or only cement) and figure out which binder leads to the best pavement performance. Three road sections rehabilitated in 2000, 2003, and 2005 were analysed. The performance of the entire pavement structure was evaluated in terms of the International Roughness Index, rut depth, and pavement surface distress in 2013 and 2017.


Author(s):  
A. Drescher ◽  
D. E. Newcomb ◽  
W. Zhang

The diametral indirect tension test is a convenient configuration for determining the modulus of asphalt concrete samples. The resilient modulus test has been a traditional approach to characterizing the stiffness of asphalt concrete, but it leaves much to be desired when considering the viscous behavior this material exhibits, even at low temperatures. A method for determining the complex compliance, complex modulus, and phase angle of asphalt mixtures using the indirect tensile test and a haversine load history is presented here. This test may be performed over a range of frequencies and temperatures as demonstrated on materials used in the Minnesota Road Research Project. The use of the haversine loading simplifies the test when compared with the pulse loading and rest time used in the resilient modulus test, and it allows for the characterization of the elastic and viscous components of the material's overall behavior, which is very difficult, at best, with the current test methods.


2016 ◽  
Vol 700 ◽  
pp. 227-237 ◽  
Author(s):  
Siti Nur Amiera Jeffry ◽  
Ramadhansyah Putra Jaya ◽  
Norhafizah Manap ◽  
Nurfatin Aqeela Miron ◽  
Norhidayah Abdul Hassan

Significant quantities of coconut shell (CS), a by-product of agriculture, can be used as an artificial source of coarse aggregates. In this study, four CSs were used as coarse aggregates replacement in asphalt concrete with 0%, 10%, 20%, 30%, and 40% weight volumes. The particle sizes of the CSs used as main coarse aggregates range from 5 mm to 20 mm. The Marshall Stability test shows that the optimum bitumen content for asphalt mixtures is 5.1%. The engineering properties investigated include the volumetric, dynamic creep, indirect tensile strength, and resilient modulus. Test results show that stability decreases with increasing CS content because of high water absorption. Considering that CSs absorb bitumen, a further detailed investigation is needed to assess the performance of modified bitumen on mixture. Furthermore, the use of CSs as coarse aggregates in asphalt concrete help increase the resilient modulus, stiffness, and indirect tensile strength up to 30%. Generally, a 10% replacement of coarse aggregates with CSs is the optimal limit.


2016 ◽  
Vol 10 (1) ◽  
pp. 511-523 ◽  
Author(s):  
Li Limin ◽  
He Zhaoyi ◽  
Liu Weidong ◽  
Hu Cheng ◽  
Liu Yang

To solve the problem of rutting and fatigue damage to asphalt pavement, rutting and fatigue performances of Qingchuan rock asphalt modified asphalt were studied, based on the dynamic shear rheometer test, the dynamic creep test, the rutting test, the indirect tensile fatigue test, the small-sized acceleration loading test, the compressive resilient modulus test, the BISAR3.0 Program and the rutting calculation method based on dynamic finite element method. The results indicate that Qingchuan rock asphalt modifier can obviously improve the anti-fatigue performance and anti-rutting performance of asphalt pavement. Taking the anti-rutting performance and the raw-material price of asphalt into consideration, a rock asphalt optimum content ranging from 5% to 8% is suggested. Qingchuan rock asphalt is a good modifier to solve the rutting and the fatigue damage of asphalt pavement.


10.6036/10174 ◽  
2021 ◽  
Vol 96 (4) ◽  
pp. 379-387
Author(s):  
Baoyong Xue ◽  
Ping Yao ◽  
Xiaolong Zou ◽  
Qian Liu ◽  
Yanlong Zhao

The erosion effect of snow-melting salt will degrade the durability of recycled asphalt pavement, but the damage characteristics of recycled asphalt mixture triggered by the erosion effect of snow-melting salt remain unclear. To solve the snow-melting salt-induced durability degradation of asphalt pavement, two commonly used snow-melting salts, NaCl and CaCl2, were selected to carry out the saline water immersion, salt-drying and -wetting cyclic and salt-freezing and -thawing cyclic splitting tests on recycled asphalt mixture, and the attenuation laws of splitting strengths and its damage characteristics under the erosion effect of snow-melting salts were analyzed. Results demonstrate that with the increase in soaking time, salt-drying and -wetting cycles and salt-freezing and -thawing cycles, the splitting strength of the recycled asphalt mixture maintain a declining trend, and the attenuation rate of splitting strength is elevated. The damage degree of the recycled asphalt mixture presents a nonlinear growth trend during saline water immersion, salt-drying and -wetting cycles, and salt-freezing and -thawing cycles. Under the same conditions, the damage degree after the action of NaCl solution is higher than that after the action of CaCl2 solution, and meanwhile, within the range of test concentration, the damage degree after the action of low-concentration saline solution is higher than that after the action of high-concentration saline solution. Conclusions provide a significant reference for the composition design and maintenance decisions of recycled asphalt pavement materials in cold regions. Keywords: road engineering; salt erosion; recycled asphalt mixture; damage characteristics; splitting strength


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