An Experimental Investigation on the Effect of Calcium Chloride As Dust Suppressant on the Strength of Unpaved Road

The quality of the gravel used in road construction has a profound positive impact on road service life. The potential use of calcium chloride as a dust control agent and material for stabilizing the base of unpaved roads has been researched. However, the quality of the gravel may be impacted if calcium chloride is introduced as a dust suppressant into it. The main aim of this research is to examine the increase in strength of soil specimens treated with calcium chloride and to evaluate how different proportions of calcium chloride as a dust suppressant and base stabilizer affect the California Bearing Ratio value of the soil samples. Mixtures of natural gravel and gravel with varying amounts of calcium chloride were analyzed for their Atterberg limits, grading, maximum dry density, CBR properties, and optimum moisture content. The changes in the characteristics of the gravel - calcium chloride mixtures were analyzed. It was found that the particle size distribution and Atterberg limits remained largely unchanged. However, the optimum moisture content (OMC) decreased from 9.2% to 7.6%, 7.4%, and 7.2% with calcium chloride added at percentages of 2 percent, 3 percent, and 4 percent per volume of dry soil, respectively. Observation of the mixture revealed an increase in the maximum dry density (MDD) as the ratios of calcium chloride were altered. The maximum dry density significantly increased from 2.15 Mg / m3 to 2.31 Mg/m3, 2.35 Mg/m3, and 2.36 Mg/m3, respectively. Along with this, the California Bearing Ratio (CBR) demonstrated an improvement of 25% to 29%, 32%, and 36% at 95% compaction with an increase in the ratios of calcium chloride. The increase in dry density can be explained by the improved bonding between particles and the reduction of air voids. This increase in dry density, in turn, positively influences the California Bearing Ratio by transforming soil structure from a dispersed state to a flocculated state. It can be inferred from the results that calcium chloride has the potential to function as a stabilizer for unpaved roads. The findings of this study are expected to reduced life cycle costs for unpaved roads, provide insights for the best approach to materials analysis for unpaved roads, and contribute to environmental benefits by minimizing dust emissions into the atmosphere and reducing the release of chemicals into nature

Modelling pedestrians’ utilisation of crossing facilities, gap acceptance and crossing decision in urban area

A pedestrian intending to cross a roadway has to decide whether to use a crossing facility or to cross a street illegally. An incorrect decision made will expose the pedestrian to the risk of accident. Pedestrian crossing behaviour has been sighted in the focus in the last decades. In the past, several studies investigating the risk of crossing a road focusing on walk trip frequency or mode choice behaviours have been conducted. Numerous factors which affect the behaviour of pedestrians have been identified. Up to now, far too little attention has been paid to pedestrian road crossing behaviour in Malaysia. The specific aim of this study was to provide new insights and develop models for pedestrian gap acceptance, crossing decision and utilisation of zebra crossings among pedestrians using regression model techniques. The critical gaps for pedestrians were estimated using Raff’s method from studies conducted at 12 locations in different regions across Malaysia. The results show that the average critical gap was 9.9 seconds. Studies on gap acceptance found that nine factors such as baggage effect, pedestrian gender, vehicle size, crossing distance and etc influenced the pedestrians’ crossing behaviour in terms of accepted gap size. Meanwhile, studies on crossing decision showed that four parameters, i.e. traffic speed, driver yield, pedestrian number and pedestrian age significantly influenced pedestrians’ crossing choice. In addition, the findings indicated that while there were three significant factors i.e. length of zebra crossing, guardrail and number of lanes that positively influenced the pedestrian utilisation rate of crossing facilities, four variables were found to have significant direct effect on the decision to use zebra crossings. The models developed for pedestrians’ use of zebra crossings, gap acceptance and crossing decision were found to be significant and thus can be used to gauge the pedestrians’ crossing behaviour in urban areas. Hence, this study would help improve pedestrian crossing behaviours and influence the local authorities to draw up street design policies and pedestrian facility specifications that will improve the safety of pedestrians and other road users in Malaysia

Modeling electro-magneto-hydrodynamic thermo-fluidic transport of biofluids with new trend of fractional derivative without singular kernel

This paper investigates the electro-magneto-hydrodynamic flow of the non-Newtonian behavior of biofluids, with heat transfer, through a cylindrical microchannel. The fluid is acted by an arbitrary time-dependent pressure gradient, an external electric field and an external magnetic field. The governing equations are considered as fractional partial differential equations based on the Caputo–Fabrizio time-fractional derivatives without singular kernel. The usefulness of fractional calculus to study fluid flows or heat and mass transfer phenomena was proven. Several experimental measurements led to conclusion that, in such problems, the models described by fractional differential equations are more suitable. The most common time-fractional derivative used in Continuum Mechanics is Caputo derivative. However, two disadvantages appear when this derivative is used. First, the definition kernel is a singular function and, secondly, the analytical expressions of the problem solutions are expressed by generalized functions (Mittag-Leffler, Lorenzo–Hartley, Robotnov, etc.) which, generally, are not adequate to numerical calculations. The new timefractional derivative Caputo–Fabrizio, without singular kernel, is more suitable to solve various theoretical and practical problems which involve fractional differential equations. Using the Caputo–Fabrizio derivative, calculations are simpler and, the obtained solutions are expressed by elementary functions. Analytical solutions of the biofluid velocity and thermal transport are obtained by means of the Laplace and finite Hankel transforms. The influence of the fractional parameter, Eckert number and Joule heating parameter on the biofluid velocity and thermal transport are numerically analyzed and graphic presented. This fact can be an important in Biochip technology, thus making it possible to use this analysis technique extremely effective to control bioliquid samples of nanovolumes in microfluidic devices used for biological analysis and medical diagnosis

Enablers for integrated operations diagnosis and improvement

In order for organizations to improve their performance, they shall identify their operations opportunities for improvement. The process to identify the opportunities for improvement is referred herein as “diagnosis” process. The most common systematic operations diagnosis and improvement approaches are Quality Audit, Organizational Assessment based on Business Excellence Framework and Project Selection for Lean and Six Sigma. All these three approaches should be integrated in order to grasp the fruitful benefits for the organizations. The benefits include; minimize redundancies, improve the operations performance and eventually assist in achieving certification and award. This paper proposes the enablers for operations diagnosis and improvement based on integration of ISO19011 Quality Audit framework, Business Excellence Framework and Lean Six Sigma approaches

A Systematic Review of the Concrete Durability Incorporating Recycled Glass

This systematic literature review (SLR) aims to present and analyze the recent research on the effect of recycled glass (RG) on the durability of concrete applications in terms of transport properties, chemical attack, alkali-silica reaction (ASR), and freeze/thaw (FT). RG could be utilized in concrete as a replacement or addition in three forms, namely glass powder (GP), glass aggregate (GA), and glass fiber (GF). The methodology of this study was based on a criterion for the selection process of reviewed studies to assess and synthesize the knowledge of the durability of RG in concrete. The articles were assessed and screened, then 114 review articles were selected. The direction of utilization of RG in concrete depends on the type, particle size, and pozzolanic performance. The valorization of RG had a positive impact on the durability of concrete; however, the mutual synergy of multiple substitutions with glass also had better results. Nowadays, fine glass aggregate (FGA) could be promoted to be used as a partial substitute for sand due to the easiness of recycling. Furthermore, GF is strongly encouraged to be used in fiber concrete. An analytical framework that highlights the durability improvement of glass-modified concrete is presented. The results suggested that it is technically feasible to utilize glass as a part of concrete in the production of durable concrete. It provides a higher resistance to transport properties and chemical attacks by providing an extended lifespan. In addition, RG plays a great role in FT action in cold climates while it does not have a significant impact on ASR, provided refinement of glass results in the reduction of ASR and thus overcomes the expansion and cracks of concrete. However, up to 20% GP and up to 30% fine glass aggregate (FGA) could be replaced with cement and aggregate, respectively, to achieve a positive effect on durability based on the W/C ratio provided, not compromising the strength

Modelling the utilization rates of pedestrian crosswalks

A zebra crossing is a form of pedestrian crossing provision point on roads that have significant volumes of traffic. It is one of the safety measures employed to reduce avoidable pedestrian-motorist conflicts and accidents on such roads. In the past several studies have been conducted on the behaviours of road users (pedestrians and motorists) especially on non-signal intersections. Although, various recommendations and solutions have been proffered to the many road-crossing challenges. But there has been little to no change in pedestrians’ perceptions and preferences of zebra crossing. Contemporary researches have tried to rectify this by applying several models to rate the use of pedestrian zebra crossing. This study uses a Regression Model Techniques to analyse factors influencing utilization rate of pedestrian zebra crossing. In this study, 450 samples were collected from 12 locations, covering school, public building, residential and business areas to examine the utilization rate of the zebra crossing by pedestrians. To examine the significance level on the crossing utilization rates by pedestrian at 95% confidence interval, a pedestrian utilization rate (PUR) was acting as the dependent variable and the remaining variables served as the independent variables. The Multiple Linear Regression (MLR) model was also used to determine the utilization rate needed to develop the zebra crossing utilization model. From the findings, the calibrated R2 value was discovered to be at 0.937 and the descriptive statistics of MLR test, t and p-values, were also found within an acceptable range. The result also showed that, out of all the variables which were used, only three have a significant effect on the utilization rates of pedestrian zebra crossing while the remaining variables have an insignificant effect. The study concluded that among the different variables, Guardrail, number of lanes and Width of zebra crossing were the most influential variables. It is believed that the conclusions drawn from this research are expected to be useful to improve the state of pedestrian facilities in Malaysia.Open Access funding provided by the Qatar National Library