Short-Term Performance of Plant-Mixed Warm Stone Mastic Asphalt: Laboratory Testing and Field Evaluation

Author(s):  
Imad L. Al-Qadi ◽  
Zhen Leng ◽  
Jongeun Baek ◽  
Hao Wang ◽  
Matthew Doyen ◽  
...  
2018 ◽  
Vol 182 ◽  
pp. 200-209 ◽  
Author(s):  
Cesare Sangiorgi ◽  
Piergiorgio Tataranni ◽  
Andrea Simone ◽  
Valeria Vignali ◽  
Claudio Lantieri ◽  
...  

Author(s):  
Alireza Joshaghani

Stone mastic asphalt (SMA) has not been widely used in the pavement industry, and there are no detailed design specifications for this type of asphalt. Therefore, long-term performance data is not available widely, and no performance model has been developed for SMA. The main purpose of this study was to integrate expert knowledge (using the Markov-chain process) and experimental data from field investigations to propose a performance model for SMA through the incorporation of the Bayesian technique. The combination of these sources of data resulted in an efficient and effective method to develop a performance model for this type of pavement, which did not have a long-term performance database. As a result, a robust linear performance model was established to predict the service life of SMA. The service life of SMA can be estimated explicitly according to the developed performance model which has been validated using a new set of data.


Author(s):  
Sajjad Noura ◽  
Abdulnaser M. Al-Sabaeei ◽  
Gailan Ismat Safaeldeen ◽  
Ratnasamy Muniandy ◽  
Alan Carter

2021 ◽  
Vol 13 (5) ◽  
pp. 2745
Author(s):  
Manoj Kumar ◽  
Ritu Dogra ◽  
Mahesh Narang ◽  
Manjit Singh ◽  
Sushant Mehan

Manual transplanting, a pre-dominant practice in almost all the paddy growing areas in India, is laborious, burdensome, and has many expenses on raising, settling, and transplanting nursery. The transplanting process’s limitations motivated the replacement of conventional paddy transplanting methods. The study was divided into two phases. The first phase included laboratory testing of three levels of metering mechanisms, namely cell type (M1) with 10 cells grooved around a circular plate having a 13 cm diameter, inclined plate (M2) containing 24 U shaped cells provided on an 18 cm diameter plate, and fluted roller (M3) with 10 flutes on a 5 cm diameter shaft. The testing matrix included a missing index, multiple index, and seed damage with forward speeds (2.5, 3.0, and 3.5 km/h), and pre-germination levels of 24 h soaked (P1), 24 h pre-germinated (P2), and 36 h pre-germinated paddy seeds (P3)). The second phase included selecting the best combination obtained from the laboratory study and developing a new efficient planter for the puddled field. The inclined plate metering mechanism operating at 2.5 km/h for 24 h pre-germinated seeds was reported most efficient from the first phase. Therefore, a self-propelled 8-row planter equipped with an inclined plate metering mechanism having a row-to-row spacing of 22.5 cm was developed, fabricated, and evaluated in the puddled field. The designed planter was assessed on two different soils: sandy loom (ST1) and clay loom (ST2) and at two different hopper fill levels as ½ filled hopper (F1) and ¾ filled hopper (F2). The number of plants per square meter and hill-to-hill spacing was measured. The on-field evaluation revealed that the number of plants per square meter was non-significantly affected by the type of soil but was significantly affected by hopper fill.


Author(s):  
Ekarizan Shaffie ◽  
◽  
H.A. Rashid ◽  
Fiona Shiong ◽  
Ahmad Kamil Arshad ◽  
...  

Stone Mastic Asphalt (SMA) is a gap-graded hot mixture designed to provide higher resistance towards permanent deformation and rutting potential by 30% to 40% more than dense-graded asphalt, due to its stable aggregate skeleton structure. However, compared to other types of hot mix asphalt, SMA unfortunately has some shortcomings in term of its susceptibility towards moisture-induced damage due to its structure and excessive bitumen content in the composition. This research aims to assess the performance of a SMA mixture with steel fiber by enhancing overall stability, abrasion resistance, and, most importantly, moisture susceptibility. This study involved the incorporation of various steel fiber proportions of 0%, 0.3%, 0.5% and 0.7% by the total weight of mixture. The steel fiber modified SMA was made up of 6.0% PEN 60/70 bitumen content. The performance of SMA were evaluated through Marshall stability and flow test, Cantabro loss test and indirect tensile strength test. The results obtained from the testing showed that the incorporation of steel fiber is significantly effective to enhance the resistance towards moisture damage, while increasing the stability and reducing the abrasion loss of SMA mixture, compared to conventional mixture. Overall, it can be concluded that the addition of steel fiber in asphalt mixture specifically SMA, has improved the mechanical performance in the application of asphalt pavement with the optimum steel fiber proportion of 0.3% by the weight of mixture. The developed models between the independent variables and responses demonstrated high levels of correlation. The study found that Response Surface Methodology (RSM) is an effective statistical method for providing an appropriate empirical model for relating parameters and predicting the optimum performance of an asphaltic mixture to reduce flexible pavement failure.


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