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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.

Objectives This study aims to examine medical waste management (MWM) practices and identify the challenges of optimal MWM at the primary healthcare (PHC) level in Kebbi State, Nigeria. Study design This study was a cross-sectional survey of 265 primary healthcare workers (PHCWs) and health facilities (HFs) in Kebbi State. Methods The study tool used was a questionnaire adapted from the WHO rapid assessment tool on MWM and water sanitation. Descriptive and inferential statistical analyses were conducted using SPSS version 20 software. Results Data generated from 257 HWs were used in this study. Amidst other findings, only 65 (25%) HFs had MWM guideline or policy document; out of these 65HFs, only 19 (7%) of them had problem with its implementation. Only 42 (16%) HFs had a compensation package or a health insurance policy to take care of their health workers in case of MWM-associated hazards while 22 (9%) HFs had specific budgetary allocation for MWM. Only 105 (41%) HFs had trained staffers on MWM. Sharps, blood/body fluids and domestic wastes were the top three (3) wastes generated among the surveyed HFs. Medical waste treatment was on-site in 124 (48%) HFs and burn-and-bury method was the adopted method of medical waste disposal in 198 (77%) HFs. However, the majority (76%) of the surveyed HWs expressed dissatisfaction about the waste treatment practices adopted in their HFs. Conclusion Our study revealed a poor level of MWM practices in Kebbi State, Nigeria. The state government and partners need to urgently address the identified operational and policy gaps in MWM in Kebbi State, Nigeria. Furthermore, our study revealed the negative implication of fragmented governance and leadership structure at the PHC level on policy, practice and administration of medical waste management in the Kebbi State, Northwestern Nigeria. Addressing the gaps found in this study would contribute to the attainment of the United Nations Sustainable Development Goals in health and well-being, sustainable cities and communities and contribute to poverty eradication.

Fatigue cracks and rutting deformation are the key distresses affecting flexible pavement. The characteristics of recycled polyethylene terephthalate (PET) fiber were studied for the improvement of asphalt concrete performance against these distresses. Water absorption of recycled PET was found to be 0.18% which is very low. Tensile strength of recycled PET fiber was 218 MPa which is enough to improve the performance of asphalt mixture. The reinforcement of asphalt mixes was conducted by adding 0.3%, 0.5%, 0.7%, and 1.0% of recycled PET fiber content by total weight of mixture. Static creep test was conducted on neat and PET fiber–reinforced asphalt mixtures. The result indicated improvement in resistance to permanent deformation and accumulated at 0.5% PET fiber–reinforced mixtures. To investigate the response of neat and recycled PET fiber–reinforced mixtures, resilient modulus test was conducted. The result shows a considerable improvement of resilient modulus at both 25oC and 40°C of recycled PET fiber–reinforced mixtures compared to neat mixture. This is also an indication of improved fatigue and rutting resistance. Generally, mixtures containing 0.5% recycled PET fibers performed better. Thus, it can be concluded that 0.5% recycled PET fiber is the optimum percentage for improvement of fatigue and rutting resistance of asphalt mixture.

One of the effects of water in bituminous pavement is the stripping of aggregates from the mixture causing severe distresses such as potholes. In this study, fiber was produced using recycle plastics and it was used as reinforcement in bituminous mixture against moisture damage. The reinforcements were 0.3%, 0.5% 0.7% and 1.0% of the total weight of bituminous mixture with a view to determine the effective fiber dosage. The stripping potential of control and fiber reinforced mixtures were determined using moisture susceptibility test. From the test results, highest tensile strength ratio (TSR) was obtained in mixtures containing 0.5% recycle plastic fiber. The result also indicated higher indirect tensile strength for both dry and saturated at 0.5% plastic fiber reinforcement. For 0.7% and 1.0% recycle plastic fiber reinforced bituminous mixture, both tensile strength and tensile strength ratio were low compared to that of control mixture. From this study, reinforcing bituminous mixture using 0.5% recycle plastic proved to be effective in improving stripping resistance.

Climate change is often used interchangeably with the term global warming but, it is a much broader term which includes global warming and some other climate changes that are observed on our planet over the last few decades. In recent time climate change impacts are being felt, the average global temperature is on the rise every decade since the 1970s. Sea ice and glaciers are disappearing, rising sea levels, species are becoming extinct, droughts that render landscape more susceptible to wildfires, changing seasons and severe weather events are becoming more common. These are problems primarily caused by the emission of greenhouse gases into the environment that results to rise in global temperature. There seems to be a consensus among scientist, researchers and all other stakeholders that climate change is already happening and primarily caused by human activities, a few disagree with this view and attribute climate change as a natural phenomenon. The objective of this paper is to (i) introduce climate change in our world today, (ii) enumerate significant causes of climate change in our environment, as well as the effects (iii), suggest ways the impact of climate change due to GHG emissions and other contributors can be mitigated.

The study aim is to determine the suitability of recycled polyethylene terephthalate (PET) fiber in fatigue life improvement of asphalt concrete mix. Fatigue crack is among the principal distresses that shortens the life span of flexible pavements. The aim was achieved through laboratory experiments (indirect tensile stiffness modulus and fatigue tests) to determine the fatigue characteristics of reinforced and neat asphalt mixtures. The reinforced mixtures were prepared using recycled PET fiber at 0.3, 0.5, 0.7, and 1.0% by total weight of mixture. The result was analyzed through regression analysis and fatigue life-prediction models were developed. The stiffness modulus of reinforced mixtures was improved by 19% at 0.3%, 34% at 0.5%, 4% at 0.7% and decreased by 34% at 1.0% recycled PET fiber reinforcement compared to neat mixture. The developed fatigue life-prediction models are statistically significant with p-values < 0.05. The fatigue life of recycled PET fiber reinforced mixtures at higher strains was highly improved at 0.3% reinforcement, while 0.5% reinforcement exhibited higher fatigue life at lower strain levels compared to neat mixtures. Therefore from the result and analysis conducted, recycled PET fiber has proved to be effective in fatigue life improvement of asphalt concrete.

Reclaimed asphalt pavement (RAP) usage has increased recently due to the decreasing supply of liquid asphalt and concerns over adverse health effects when making use of petroleum-based/chemical recycling agents which increased the need for bio-based recycling agents designed to return the RAP binder to its original state. The objective of this study is to investigate the possibility of using jatropha curcas oil (JCO), which is a non-edible oil (do not compete with the food chain) that cannot be used for nutritional purposes due to the presence of anti-nutritional factors, such as phorbol esters, as a bio-base rejuvenating agent for aged bitumen. The physical properties and storage stability of the bio-oil, original bitumen, aged bitumen and rejuvenated bitumen were measured. The results of the investigation indicated that the bio-oil have potential to rejuvenate aged bitumen to condition that resembled the original bitumen, the use of the bio-oil show benefits from both health and environmental perspectives. Also the rejuvenated bitumen was found to be very stable in term of storage.

Objectives: To determine the reinforcing effect of a cheap Recycle Polyethylene Terephthalate (PET) fibre on asphalt concrete strength. The aim of this study was achieved by performing Resilient Modulus (MR) test in the laboratory on both unreinforced (i.e. neat asphalt mixture) and recycle PET fibre reinforced asphalt concrete mixtures. Methods: The percentage additions of recycle PET fibres are 0.3%, 0.5%, 0.7% and 1% of the total weight of the mixture. The result was analyzed by means of Response Surface Methodology (RSM) using Design Expert 7.0 software and validated using analysis of variance (ANOVA). Findings: The results indicated that recycle PET fibres have significantly increased the mixtures’ resilient modulus in lower temperature hence improved fatigue resistance, and moderately increased mixtures, resilient modulus at higher temperature hence improved rutting resistance. Novelty/Improvement: This research has introduced a sustainable means of producing Recycle fibres for the reinforcement of asphalt concrete mixtures. Recycle PET fibre have proved to be effective in strength improvement at 0.7% of total weight of asphalt concrete mixture.

The fact that Jatropha curcas oil cannot be used for nutritional purposes without detoxification makes its useful as energy or fuel source, which will improve the domestic economy and provide job opportunities particularly in rural areas, where mechanical pressing is currently the most extensively used process to extract oil from seed. In this context, the main goal of this study is to provide a summary of several studies dealing with the currently employed oil extraction technologies, the physicochemical properties of bio-oils obtained from J. curcas, and the potential uses of Jatropha oil. The aim is to shed light on the main differences among the four types of oil extraction techniques currently employed and to highlight their most appropriate applications. If tapped efficaciously, then these techniques could prove to be extremely helpful in these days of power and environmental crises.

Concerns about the cost, availability, and environmental impact of using petroleumbased materials have led to increased usage of reclaimed asphalt pavement (RAP). Meanwhile, the demand of the road industry to decrease the energy consumptions and reduce the release of greenhouse gases as well as other harmful gases, which cause serious air pollution has increased due to the amount of energy consumed is a major component of pavement construction that significantly contributes to the total cost. This paper evaluates the effects of Biobased rejuvenator known as JCO on the required heat energy and the amount of CO2 produced to increase the temperature of RAP and virgin aggregates and one binder from 25C to the point of mixing. The results showed that incorporating Biobased rejuvenator (JCO) can potentially reduce the required heat energy and amount of greenhouse gas produced by RAP and virgin, respectively.