Investigation into Effectiveness of By-pass Cement Dust as Soil Stabilizer in Road Construction

Abstract By-pass cement dust (BPCD) is produced in large amount

Experimental Study of using Waste Glass as additives in Asphalt Concrete Mixtures

In road engineering, it is important to develop paving technology and improving asphalt pavement efficiency in terms of increasing their service life and reducing the damage caused by rutting, fatigue and thermal cracks. Waste glass can be used as asphalt modifiers, which can be add in certain properties to the asphalt mixture in ordered to modify some of the properties of  the mechanical properties of asphalt concrete mixtures. The waste glass that is crushed can be used as a portion of fine aggregate in asphalt concrete mixtures. The aim of this research is to study the effect of using waste glass as asphalt concrete mixtures additives. From the review different portion of waste, glass can be used as asphalt concrete mixtures additives up to 15%. In this research fine natural aggregate replaced with crushed Waste glass in deferent percentage namely 6%, 9%, 12%, 15% and 18%. The mechanical properties of the glass-asphalt were evaluated using Marshall Stiffness, compressive strength and indirect tensile strength. Based on the results, it was found that 15% of crushed Waste glass improves the mechanical properties of asphalt concrete mixtures in the terms of Marshall Stiffness and compressive strength. On the other hand, no improvement in the tensile strength was noticed

THE EFFECTS OF ADDING RECLAIMED ASPHALT PAVEMENT (RAP) AND CEMENT ON THE PROPERTIES OF PAVEMENT BASE COURSE

Reclaimed Asphalt pavement (RAP) is removed using a milling machine which grinds the asphalt into small pieces and it is a useful alternative to virgin materials because it reduces the use of virgin aggregate. Base course is a layer that comes under the surface layer of asphalt pavement and consists of gravel materials with lower specifications than the surface layer. The main aim of this research is to evaluate using reclaimed asphalt pavement and Portland cement as stabilizer to the base course materials. Different amount from RAP materials were added to the base course soil by weight. The RAP percentage added are 5%, 10%, 15%, 20% and 25% with fixed amount of cementing 2% for all mixtures. Different tests were conducted sieve analysis, Los Angelos Abrasion, Modified Proctor and California bearing ratio. The results showed that adding recycled asphalt to the base soil improved all mixtures properties with different rate. After adding recycled asphalt and cement, the sieve size analysis of the mixtures with different proportions of components still falls within the limits of the Egyptian standard. There is a noticeable improvement in the wear value for the mixture, 20% recycled asphalt and 2% cement, with a value of about 15%, and this value is good for improving the wear resistance of the mixture. The dry density value increase by 10% for the mixture, contain 20% recycled asphalt and 2% cement. California bearing ratio test result indicate that adding recycled asphalt to the soil improve the bearing capacity of soil that can be used as base course of pavement. The whole results of the research give good indication for pavement full depth recycling and reuse it as anew base course layer

Evaluation of Fatigue Resistance for Modified Asphalt Concrete Mixtures Based on Dissipated Energy Concept

The performance of asphalt concrete pavement depends on the bitumen properties, asphalt concrete mixtures volumetric properties and external factors such as traffic volume and environment. Bitumen is a visco-elastic material where temperature and rate of load application have a great influence on its behavior. Conventional bitumen is exposed to a wide range of loading and weather conditions; it is soft in a hot environment and brittle in cold weather. Higher traffic volume produces high stress within pavement layer, which is one of the main causes for pavement distress. Fatigue cracking and permanent deformation is considered as most serious distresses associated with flexible pavements. These distresses reduce the service life of the pavement and increase the maintenance cost. To reduce the pavement distresses there are different solutions such as adopting new mix design or by using asphalt additives. Using of asphalt additives in highway construction is known to give the conventional bitumen better engineering properties as well as it is helpful to extent the life span of asphalt concrete pavement. In this research an investigation was made on the fundamental studies of modified asphalt binder and mixtures in order to understand the influence of modifiers on the rheological properties and fatigue resistance with the aim of preventing fatigue cracking in asphalt pavement. The conventional bitumen (70/100) penetration grade was used in this research, modified with crumb rubber (CR) and styrene-butadiene-styrene (SBS) at four different modification levels namely 3%, 5%, 7% and 10% by weight of the bitumen. The rheological properties and fatigue resistance tests for asphalt binder were performed using a dynamic shear rheometer apparatus. Fatigue life for asphalt binder and mixtures were calculated based on the dissipated energy concept as well as a procedure for modifying of conventional bitumen was developed to find the suitable blending time and the optimum modifier content. From the results at low rubber content 3% and 5%, the behaviour of the modified bitumen remains close to that of the conventional bitumen and the optimum crumb rubber content for good rheological properties and long fatigue life was found to be 10% by the weight of bitumen. At higher (SBS) polymer content 7% and 10%, the behaviour of the modified binders remains close to that of the modified bitumen with 5% (SBS) and the optimum (SBS) content was found to be 5%. The fatigue behavior of modified bitumen was found to be significantly improved compared to conventional bitumen. Fatigue test using dynamic shear rheometer was found to be costly and time consuming. 3D finite element model for dynamic shear rheometer has been developed and was used for dissipated energy calculation. The experimental result and the model result showed excellent fit between dissipated energy for the same tested bitumen. On the other hand, a shift factor was found between the dissipated energy per volume from the bitumen specimen in dynamic shear rheometer and dissipated energy per volume for asphalt concrete mixtures in indirect tensile fatigue test

Bituminous Pavement Reinforcement with Fiber: A Review

This paper attempts to display, analyze and discuss the literature affiliated to the previous research data on road surfacing in pavement engineering reinforcement. In this paper, a review of the background and present status of road surfacing is also provided for supportive explanation of the significance of fiber-reinforced asphalt pavement HMA and its role in providing effective and durable surfacing for heavy-trafficked roads. The paper attempts to clarify some of the terms and notions related to the discussions to give the readers the needed background, to be able to actively understand the experiments and discussions. Results from many studies confirm that fiber specifically enhances the optimum bitumen content in the design of the mixture and halts the bitumen leakage due to its asphalt absorbing susceptibility. Fiber modifies the visco-elastic response, susceptibility against moisture, increase resistance to rutting, as well as lowers the pavement fatigue cracking