Study on Construction Technology of Warm Mix Asphalt Batching

2021 ◽  
Keyword(s):  
Warm Mix Asphalt ◽  
Construction Technology

scholarly journals Model Development for the Prediction of the Resilient Modulus of Warm Mix Asphalt

2020 ◽  
Vol 6 (4) ◽  
pp. 702-713
Author(s):  
Huda Mahdi Saleh ◽  
Amjad H. Albayati
Keyword(s):  
Hot Mix Asphalt ◽  
Resilient Modulus ◽  
Model Development ◽  
Warm Mix Asphalt ◽  
Coefficient Of Determination ◽  
Repeated Loading ◽  
Construction Technology ◽  
Recoverable Strain ◽  
Load Duration ◽  
Experimental Part

Increasing material prices coupled with the emission of hazardous gases through the production and construction of Hot Mix Asphalt (HMA) has driven a strong movement toward the adoption of sustainable construction technology. Warm Mix Asphalt (WMA) is considered relatively a new technology, which enables the production and compaction of asphalt concrete mixtures at temperatures 15-40 °C lower than that of traditional hot mix asphalt. The Resilient modulus (Mr) which can be defined as the ratio of axial pulsating stress to the corresponding recoverable strain, is used to evaluate the relative quality of materials as well as to generate input for pavement design or pavement evaluation and analysis. Based on the aforementioned preface, it is possible to conclude that there is a real need to develop a predictive model for the resilient modulus of the pavement layer constructed using WMA. Within the experimental part of this study, 162 cylindrical specimens of WMA were prepared with dimensions of 101.6 mm in diameter and 63.5 mm in thickness. The specimens were subjected to the indirect tension test by pneumatic repeated loading system (PRLS) to characterize the resilient modulus. The test conditions (temperature and load duration) as well as mix parameters (asphalt content, filler content and type, and air voids) are considered as variables during the specimen’s preparation. Following experimental part, the statistical part of the study includes a model development to predict the Mr using Minitab vs 17 software. The coefficient of determination (R2) is 0.964 for the predicted model which is referred to a very good relation obtained. The Mr value for the WMA is highly affected by the temperature and moderately by the load duration, whereas the mix parameters have a lower influence on the Mr.

Construction Technology of Warm Mix Retardant Asphalt Mixture

2013 ◽  
Vol 361-363 ◽  
pp. 1477-1483 ◽  
Author(s):  
Hong Zhao ◽  
Xiu Shan Wang ◽  
He Quan Lu ◽  
Xiao Ling Lu
Keyword(s):  
Asphalt Mixture ◽  
Material Design ◽  
Warm Mix Asphalt ◽  
Construction Technology ◽  
Construction Quality ◽  
The Road ◽  
Environment Quality ◽  
New Material ◽  
Design Construction

As a new material, the warm mix asphalt retardant asphalt mixture has its particularity in material design, construction proportion, mixture preparation and on-site paving. This paper summarized the construction process and site construction quality inspection requirement of the warm mix asphalt retardant asphalt mixture through tracking research on-site based on the real engineering. It was shown that the road environment quality of using warm mix retardant asphalt was significantly better than normal hot mix asphalt, asphalt smoke, benzene soluble and Benzopyrene decreased 91.47%, 97.05% and 80.11% respectively. Warm mix asphalt retardant asphalt mixture had a low mixing and compaction temperature. When used in the tunnel pavement, it could not only greatly reduce harmful gas emissions in the process of construction, improve construction environment in tunnel, improve the air transparency in tunnel, be convenient for construction quality management, but also can improve the fire resilience of the tunnel pavement after be put into operation. It had broad application prospect in the tunnel pavement.

On the Job Training (OJT) Assessment for Diploma in Construction Technology

2020 ◽  
Vol 17 (2) ◽  
pp. 29
Author(s):  
Nurhafizah Abdul Musid ◽  
Haryanti Mohd Affandi ◽  
Nurul Eizzaty Sohimi ◽  
Mohd Firdaus Mustaffa Kamal
Keyword(s):  
Attitude Change ◽  
Job Training ◽  
Change Implementation ◽  
Construction Technology ◽  
Validity And Reliability ◽  
Structured Interviews ◽  
Vocational College ◽  
Technology Students ◽  
Assessment Problems ◽  
Assessment Rubric

On Job Training (OJT) is best for skill development and attitude change. Implementation of OJT which focuses on the transition of students to working life, however with little attention given to the process of assessment in OJT. Therefore, the aim of this study is to investigate the OJT assessment problems among Construction Technology students in Malaysian Vocational College. The research design for this study uses a survey that was carried out qualitatively through semi-structured interviews among Construction Technology students, lecturers and experienced construction practitioners. From the data analysis, it has been identified that there is an inadequacy of OJT assessment rubric in assessing the skill and knowledge of the construction technology students. This has been contributed with the used of holistic rubric for the OJT assessment which has been designed to be use by every course in the Vocational College. The result also revealed that allocation of marks in the assessment rubric is not commensurate with some construct assessed and need to be reviewed. This study shows that an assessment rubric should emphasizes on specific knowledge and skills in assessing students’ competency during training program and in this case to produce competent site supervisor. In addition, a good assessment rubric should consider the tasks and marks thoroughly to avoid biasness among students. Therefore, it is suggested to carry out further study in investigating the validity and reliability of current industry’ OJT assessment rubric for the Construction Technology students.Key Words: On Job Training; Construction Technology; An assessment rubric; Competency; Validity and reliability.

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