Effects Of Rh-Wma Additive On The Rheological Properties Of Reclaimed Asphalt Binders And The Engineering Properties Of Recycled Mixtures

Reclaimed asphalt pavement (RAP) utilization is an option as a sustainable pavement due to its economic and environmental benefits. However, the use of high RAP content in pavement construction implicates high production temperature and hence increasing energy consumption and environmental problems during the asphalt mixture production. Higher asphalt mixture production and compaction temperatures are needed because the RAP binder is oxidized and stiffened. Asphalt mixtures with very high stiffness are more susceptible to fatigue failure. This explains the reason why RAP usage is limited particularly in areas with high amount of aggregates resources. Therefore, this research investigates the performance of a relatively new warm mix asphalt (WMA) additive named RH-WMA additive to reduce asphalt production temperatures. The optimum RH-WMA content was determined through asphalt binder rheological tests. A total of 3% RH-WMA additive by mass of asphalt binder, was incorporated into the recycled asphalt binder and mixture. The effects of RH-WMA additive on recycled asphalt binder and mixture were investigated via chemical properties, rheological properties and mixtures performance test, respectively. The test results showed that the incorporation of RH-WMA additive with asphalt binder decreased the viscosity at high temperature and improved fatigue resistance at intermediate temperature. Viscosity reduction was also observed when RH-WMA additive incorporated with recycled asphalt binder and hence indicated the potential to reduce the production temperature of the RAP mixture. The Fourier Transform Infrared (FTIR) test result showed the ability of RH-WMA additive to reduce the effects of aging. The reduced effects on aging is also shown in the rheological master curves at high frequency and/or low temperature. From the rheological master curves, the addition of RH-WMA additive increased the complex modulus and reduced the phase angle values compared to the control sample. This observation showed that the recycled asphalt binder incorporated with RH-WMA additive showed potential improvement in rutting resistance. The optimum binder content (OBC) results based on response surface method (RSM) and multi criteria optimization in recycled asphalt mixture with RH-WMA additive production indicated the significant effects of mixing temperature on the OBC. The performance of recycled asphalt mixtures were improved in terms of stiffness and resistance to rutting. However, the asphalt mixture’s ability to resist fatigue decreased considerably when stiffer RAP from locations R1 and R3 were incorporated in the virgin mixture. The incorporation of RH-WMA additive improved the mixture’s resistance to fatigue. The combined effects of moisture and aging also decreased the fatigue resistance of all mixture types in comparison with unconditioned specimen. In general, the addition of RH-WMA additive can potentially balance the adverse effects of RAP stiffness and hence maximize the benefits of RAP usage

Green Road Construction Using Reclaimed Asphalt Pavement with Warm Mix Additive

Environmental impact and emissions produced from asphalt road construction, promote research on green materials by combining the recycling and warm mix asphalt additive which aims to reduce the environmental impacts. This study evaluates the effects high reclaimed asphalt pavement (RAP) content incorporated with wax warm mix asphalt additive. Milled reclaimed asphalt pavements obtained from local roads were incorporated with a warm mix additive named RH-WMA. These materials were evaluated for the physical and rheological properties, optimum binder content and mechanical properties. It was found that RH-WMA has softening effects on the binder. The additions of 3% RH-WMA content into 40% RAP mixture decreased the optimum binder content and energy consumption. Tests on mechanical properties indicated increased on stiffness with the addition of RAP which indicated better resistance to rutting. Additions of RH-WMA on specimens that subjected to combined effects of moisture and aging showed improvement in fatigue resistance. Hence, integration of RAP and RH-WMA showed potential as a green road construction material

Fracture properties of reclaimed asphalt pavement mixtures with rejuvenator

Reclaimed asphalt pavement (RAP) technology has been extensively promoted to conserve depleting virgin materials for asphalt mixtures. High RAP content is desirable from economic and environmental standpoints. However, RAP mixtures become too stiff and require modification such as rejuvenator. This paper presents the evaluation on the fracture characteristics of mixtures prepared with 50% and 70% RAP, with and without rejuvenator that were subjected to indirect tensile strength (ITS) and notched semi-circular bending (SCB) tests. The fractured surfaces of the tested specimens were quantified using geospatial imaging technique to identify the proportion contribution to failure, namely cohesive, adhesive and broken aggregates. The results showed that the fractured rejuvenated mixtures were predominantly of the cohesive type when compared with the non-rejuvenated mixtures. On the other hand, the failure modes of non-rejuvenated mixtures were of the adhesive and aggregate failure types. The measured ITS at two temperatures corresponded with the expected damage trends. Similar behaviour was found in the derived fracture energy and pre-peak slope that were obtained from the SCB pure tensile and tensile-shear load–displacement curves. The findings showed that the fracture properties of rejuvenated mixtures performed comparably with virgin mixtures in terms of fracture toughness, tensile strength and proportion of damage contribution

Compressibility Behaviour of Borneo Tropical Peat Stabilized with Lime-Sand Column

Construction on peat soils can have two alternatives, either to excavate and replace the weak soil or to improve the soil strength using soil stabilizers such as lime and other ground improvement method such as soil column. This paper studies the properties of Borneo tropical peat soil and the effect of lime-sand-column to the value of the void ratio, the coefficient of consolidation, volume compressibility, and compressibility of the stabilized soil. After the engineering properties of the peat were determined, consolidation test was performed to observe the effect of the lime-sand column for 1 and 3 curing days with lime percentages of 3 and 6% lime. Tests were then repeated using a different number of lime-sand column. It was observed that the compressibility of the peat soil was reduced using a longer period of curing, a higher percentage of lime, and a higher number of sand columns

Supply chain and life cycle cost of roofing in Sabah: a case study

The roofing industry in Sabah has undergone marked changes and improvement in its quality and performance for the past 20 years in response to changes in local environment. In recent years, an increasing number of practitioners in the roofing construction industry in Sabah have observed that information related to roofing selection in terms of suitability and cost effectiveness is limited. This paper reports the results of an investigation on the supply chain of roofing materials in Sabah. All data were obtained based on information gathered through questionnaires, site visits and interviews with number of practitioners working in related fields such as developers, engineers, contractors, roofing manufacturers, suppliers, government agencies and occupiers. Recommendations to rectify the identified weaknesses along the supply chain have been suggested. Besides that, comparative life cycle cost analysis was carried out based on source of roofing, maintenance planning and installation alternative. Life cycle cost comparison study proved that the roofing system obtained through distributor agents gave the lowest total life cycle cost (TLCC) and highest net saving, while, roofing system obtained through stockists gave the highest TLCC and lowest net saving. Proper maintenance planning and quality of roofing system were identified as the main factors that influenced the life cycle cost valu

Maximization of waste recycling in pavement maintenance project

The most common method of recycling in road maintenance projects in Malaysia is in situ recycling. To maximize waste recycling, plant recycling can be an option since previous studies indicated good performance using reclaimed asphalt pavement (RAP). However, variability in RAP and mixing temperature are the main concerns in plant recycling. Hence, this study investigates the maximization of waste recycling from road maintenance projects in Malaysia for plant recycling in terms of quality control and the environment. The experimental design consists of materials characterization for three sources of RAP, determination of mixing temperature, analysis of environmental and energy consumption, and optimization of RAP production. The findings showed that based on RAP gradation the quality control in terms of RAP variability was less than 15% coefficient of variance and considered acceptable. The addition of RAP stiffened the RAP mixture which result in increased viscosity and mixing temperature. Higher mixing temperatures produced more greenhouse gas emissions and energy consumption. Optimization of RAP production indicated that in order to maximize the RAP usage, 50%RAP content added with RH-WMA at 140°C mixing temperature was the most ideal. The proposed design approach and evaluation of waste materials adopted in this study are beneficial for assessing the essential criteria for maximizing waste recycling in the pavement

Analysis of passengers perception on public transport facilities at Kota Kinabalu Sabah

Quality of public transport plays a major role in growing the demand for public transportation in Kota Kinabalu, Sabah. Analysis of passenger perceptions of public transport facilities in Kota Kinabalu was studied by interview methods and survey questions. The respondents were consist of public bus users and operators. The collected data were analysed using SPSS 26 and thematic analysis. As a result of the findings of the analysis made on the cleanliness of public transport, most passengers stated bad because most public transport are in a relatively old and old condition. In addition, the perception of passengers also on the environment of bus terminals and bus stops, passengers stated that the environmental conditions of these two facilities are unsatisfactory

A Study of Roundabout Sustainability using Traffic Simulation - A Case Study at Ayer Hitam Signalised Intersection

Through urban planning and municipal administration, a sustainable city seeks to solve issues of social, environmental, and economic effect. By integrating environmentally friendly options into local infrastructure, many sustainable efforts are made possible. Vehicle emissions from the road traffic have always been considered one of the most significant sources of global issues due to their harmful effects on the environment and human beings. Additionally, it is currently a concern for sustainability, especially in urban areas. This matter has inspired the researchers to simulate various systems to identify factors and provide solutions for the issue of emission. In this study, VISSIM software was utilised to develop a traffic simulation to estimate emissions level at Ayer Hitam’s signalised intersection in reference to the intersection type as an independent factor. The signalised intersection and a roundabout were chosen to represent controlled and uncontrolled intersections. It aimed to compare the difference in emissions level between the signalised intersection and roundabout. The results of this study show that roundabouts are more effective in enhancing traffic flow than signalised intersections in terms of travel time, delay, queue and have 48.59% lower for (CO), (NOx) and (VOC) emission. An improvement in vehicle emissions results from this study indicates that roundabouts have the potential to contribute to a more sustainable transportation system and sustainable city

Utilization of Micronized Polyethylene Terephthalate (MPET) as a Filler in Asphalt Pavement

Nowadays, plastic pollution is one of the most critical issues related to sustainability development that need to be solved. Studies indicated that addition of certain amount of recycled plastic from Polyethylene Terephthalate (PET) in asphalt mixture has improved the engineering properties such as marshall stability, moisture resistance, rutting and fatigue resistance. However, the main challenge of direct incorporation of recycled plastic in binder is the thermal incompatibility of two phases which are glass transition and melting temperature. Previous research findings indicated that reduction in particles diameter to micro scale would decrease the PET melting point. Hence, this study investigates the potential of micronized PET from recycled plastic bottle as filler in asphalt pavement. Micronization process at laboratory was carried out to determine the appropriate method prior incorporating it into asphalt mixture. The micronized size of PET incorporated at 0%, 4%, 8%, and 12% by weight of filler is then evaluated for its volumetric properties, mechanical, and adhesion properties. The results showed that the volumetric properties of the asphalt were affected by the presence of micronized PET. The mechanical properties in terms of Resilient Modulus and Indirect Tensile Strength showed increment with addition of micronized PET. Similar trend also observed on adhesion properties. Hence, the findings indicated the potential of utilizing the recycled MPET for local road construction

Employing local cellulose fibre to reinforce the wearing course of asphalt pavement

The current state of road technology is incapable of alleviating the exponentially increasing traffic volume, that resulting in premature fatigue, cracks, accelerated ageing, permanent deformation, hydroplaning, as well as skidding. As a matter of fact, the wearing course on asphalt pavement is implied to use cellulose fibre as reinforcement. Cellulose fibre is derived from natural oil palm waste. This invention comprises formulation to maximise stability by using gap graded gradation and matrix of locally available sandstone aggregate. This study evaluates the optimum binder content of the mixture. Several asphalt specimens were produced by using 60/70 grade bitumen at bitumen content ranging from 5% to 7% with an increment of 0.5% by aggregate weight and with fibre at 0%, and 0.4% of aggregate weight added by dry process. Parameters evaluated were Voids in Mix, Voids Mineral Aggregate, Voids Filled with Bitumen, Specific Gravity, Resilient Modulus and Binder Drain Down Test. From the results, it suggests that optimum bitumen content with fibre inclusion is 6.5% of aggregate weight were comparatively has superlative result complying the standard. It was discovered that there was a substantial shift in the characteristics of the asphalt, resulting an improved pavement strength