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A higher number of highway construction projects are experiencing delays in their scheduled completion time, and this situation, in turn, leads to overrun in the schedule as well as cost. This paper mainly categorizes the causes of time overrun and provides a mathematical model for predicting the time overrun percentage, using highway projects in Northern India as a case study. A survey of randomly selected samples yielded responses from 72 contractors and 44 clients. The study depends on forty-eight factors that influence schedule delays in highway projects. Based upon the average medium fuzzy influencing value and the respective frequency index value, the time overrun causing factors were ranked and categorized under different time overrun risk categories, namely red zone, yellow zone, and green zone. The analysis of the received responses indicates complications in the land acquisition process, utility shifting, constructability under traffic, lack of project planning and design changes were the top five most critical time overrun causing factors in highway projects. The medium fuzzy influencing value and the frequency index value for these five factors were above 18% and 80%, respectively. These factors lie under the red zone and need close attention. Factor such as opposing the projects by locals also gained much importance in this study as compared to previous studies as it lies under the red zone. The prediction model developed through the application of multiple regression analysis can explain 71.9% of the variability in the data, which is an excellent indicator of the model’s expected performance.

Cohesive soils forming the subgrade layer of flexible pavements undergo excessive rutting and deformation under cyclic traffic loading and therefore, polyester fibre reinforcement has been proposed...

Fibre-reinforced soil performs similar to a blended material composite wherein randomly oriented fibres are implanted in a soil mass. The focus of the current work was to review the performance of polyester fibre on the strength, stiffness and compaction parameters of soils. Research reported in literature shows that the inclusion of polyester fibre improves the bearing strength, optimum moisture content, unconfined compressive strength and split tensile strength, and mitigates maximum dry density of soil. The key factors controlling the performance of fibre-reinforced soil are concentration of fibres, material, orientation and distribution of the fibre. It was understood that natural and cement stabilized soils characterize brittle failure, leading to catastrophic results, and the performance of fibre in imparting ductility to brittle soils was highlighted. Enhanced strength characteristics of the soil-forming the subgrade are expected to reduce the required thickness of bituminous and granular layers, leading to sustainable construction.

Coal-fired thermal power plants provide the majority of the electricity in India and generate two waste materials: fly ash and bottom ash. For their disposal, the coal ashes are blended with water and dumped in open and termed as pond ash. Bulk utilization of pond ash in construction may be a sustainable option to its disposal. Research has shown that pond ash possesses beneficial engineering properties and can be innovatively used to develop sustainable infrastructure. The present article reviews the important engineering properties of pond ash such as physical, chemical, mineralogical, microstructural and toxicity. The effect of pond ash on the strength, compaction and plasticity properties of the soils was reviewed to determine the potential to stabilize weak soils for use in sustainable pavement construction.

Bricks are the primary building blocks used for construction. During the brick manufacturing process, combustion of coal and wood leaves behind brick kiln dust—a blend of coal ash, burnt soil, wood ash and brickbats. The waste is disposed off in open areas, engaging expensive land and contaminating of soil and groundwater. Mass application of the waste in construction applications is a sustainable alternative to open disposal. The present paper reviews the important engineering characteristics of the waste such as physical, chemical, mineralogical, microstructural and toxicity. The effect of the waste on compaction, strength and stiffness of soils was reviewed. Other innovative areas of research for successful application of the waste were reviewed. The analysis of literature helps in understanding the impending benefits of the waste in stabilizing weak soils for development of sustainable pavement infrastructure.

Resilient modulus (MR) is the critical input parameter for the characterization of pavement geo-materials subjected to repeated traffic loading. The effectiveness of a material in stabilizing soil for the subgrade layer of pavement is usually assessed by MR estimated from quasi-static tests (California bearing ratio and unconfined compression strength), but these tests are not the accurate representation of repeated traffic loading, and hence the MR must be determined through laboratory cyclic triaxial test. This review examined more than 35 research papers published over the period 1995 to 2019 and identified 15 stabilizers that have been tested for soil stabilization under cyclic triaxial loading. The analysis of these articles highlights three different categories of stabilizers: first, waste materials such as fly ash, cement kiln dust, oil shale ash ground granulated blast furnace slag, dolime, bottom ash and lignin, second, chemical stabilizers such as lime, cement, lignosulfonate, sodium alginate bio-polymer and an ionic soil stabilizer and third, fibres such as polypropylene and lignin. The soils subjected to the test were organic clay and inorganic soils such as clay, sand, gravel containing soil and black cotton soil. The present paper discusses the effect of confining stress, cyclic deviator stress, number of load applications, curing period and dosage of the stabilizer on the MR of the stabilized soils. The analyses of these articles help understand the importance of cyclic triaxial test for proper characterization of stabilized soils for use in pavement construction. The fact that only a limited number of stabilizers for the soil has been studied so far, this review identifies a scope of determining the MR of materials that are potential soil stabilizers for future research.

One of the major problems which are becoming very significant and is booming worldwide in the construction industry is the problem of cost overrun. With the increase in demand to meet the need for infrastructure, the problem of cost overrun is also spreading at an alarming rate. The construction companies of India engaged in highway construction are also no longer exempted from this serious issue. The major objective of this research paper is to recognize the major causes of cost overrun in highway projects in the regions of Northern India. A broader review of literature from different sources and interactions with the experts working in highway projects was done to list down the feasible causes of cost overrun. In the next stage, a questionnaire was formulated which consisted of 35 feasible causes of cost overrun. Respondents having vast experience in the field of highway projects, participated in the survey to recognize the critical factors responsible for cost overrun. The analysis of the data was done using IBM SPSS 23 Package. The top five most critical factors causing cost overrun have been identified and discussed in this paper along with some recommendations which are useful to control cost overrun in the highway projects. The top five critical factors identified in this study are escalation in price of raw material, changes in design, conflict/lack of co-ordination between construction parties, poor financial control and constructability issues (construction under limited area, construction under traffic, right of way).

A noteworthy quantum of greenhouse gas (GHG) emissions is emitted due to the construction and maintenance of bituminous pavements and contributes to global warming. In order to curb GHG emissions, sustainable construction methods like soil stabilization with waste materials need to be incorporated in practice by engineers. In this study, the subgrade layer of pavement was stabilized with pond ash, a waste material generated from burning of coal in thermal power plants. California bearing ratio and Proctor (modified) tests were carried out to determine the strength and compaction characteristics, respectively. The proposed stabilization enhanced the bearing strength of the subgrades. The improved strength characteristics of the subgrade resulted in the reduced requirement of materials and their transportation, eventually minimizing GHG emissions. For broad applicability, the study was carried out on six different soils of altering plasticity, which is found predominantly in north India. Reduced GHG emissions justify applicability of pond ash in creating a sustainable environment.

Objectives: To reduce the life-cycle carbon footprint of a flexible pavement using RBI grade 81, a patented natural soil stabilizer. Methods: This paper outlines the common guidelines for estimation of greenhouse gas emissions associated with a pavement as per the Indian environmental conditions. California Bearing Ratio (CBR) tests were carried out on subgrade soil treated with diverse proportions of RBI grade 81. Greenhouse gas emissions due to the initial construction phase and maintenance activities over a 20 year life cycle were assessed and compared for RBI grade 81 treated and non-treated subgrades. Key sources of carbon footprint considered were construction materials and transportation with construction equipments having negligible contribution. Findings: Studies reveal significant improvement in the CBR of the subgrade soil leading to reduction of pavement layer thicknesses thereby limiting the requirements of resources that is to say materials, fuel and machinery. The total CO 2 emissions were reduced from 910.9 tonnes to 750.8 tonnes per km length of a four lane dual carriageway road by treating the subgrade soil with 4% RBI grade 81. The production of materials and transportation used to construct the project account for 93% and 7% of the total CO 2 emissions throughout the life cycle of the pavement. Improvements: Use of RBI grade 81 results in attenuation of greenhouse gas emissions which were found consequential in amassing of carbon credits, a step towards safeguarding the environment for the future generations to come.

An increase in the generation of industrial waste materials such as pond ash and brick kiln dust represents a serious threat to the earth&rsquo, s environment. The waste materials have novel characteristics and therefore their physical, chemical, mineralogical, morphological, mechanical, and toxicity characteristics were determined so that these materials can be incorporated as construction materials based on technical and environmental considerations. The purpose of this study is to utilize the wastes in the stabilization of clay geomaterial to outperform existing problems of inadequate strength and stiffness of the subgrade layer in flexible pavements. Mixtures of geomaterials, containing pond ash, brick kiln dust, and their combination were prepared and important engineering characteristics such as the plasticity, compaction, and strength of the mixtures were examined. The measurement of response to dynamic loading is a pre-condition for the accurate characterization of geomaterials used in pavement construction. Using advanced cyclic triaxial testing, this study evaluates the performance of pond ash and brick kiln dust in increasing the stiffness of the geomaterial under cyclic loading. To stimulate the worst field conditions, the stiffness and strength tests were performed under standard and four-day water-soaked conditions. The implementation of several stress-dependent models for the prediction of stiffness was examined. Pond ash and brick kiln dust were found to be effective in increasing the stiffness and strength of the geomaterial. The wastes were the most effectual when added in combination to the geomaterial. The characterization of the wastes was informative in understanding the governing mechanism prevalent in the waste stabilized mixtures. The toxicity characterization study revealed the non-toxic and non-hazardous nature of the waste materials, permitting their use in the construction of pavements. This study recommends the use of wastes in the subgrade of flexible pavements. Further research is needed for performance evaluation of the wastes on silt and sand geomaterials for their wider application.

The use of bitumen in road construction has increased many-fold throughout the world due to its compatibility, the ease in road construction and above all the advantage of allowing traffic immediately after construction. The most common binder used for road surfacing is bitumen obtained from petroleum However; Petroleum is nowadays becoming scarce due to depletion of its source. Even though bitumen is widely used in road construction, there are some drawbacks in bituminous mix like high susceptibility to temperature variation, tendency to crack, lesser effective service life etc. Therefore, bituminous pavements fail to give the expected service life under adverse climatic, environmental and traffic condition. In an attempt to enhance the service life of bituminous surfacing under adverse prevailing conditions, research is going on throughout the world in the area of additives in search of improved, durable and cost effective bituminous binders. The main objective of this study is to evaluate the properties of bituminous mixes that can be made by use of different grading of bitumen like VG10 VG30 VG40 and different grading of aggregate with using of code references.

The present study evaluated the geotechnical and geo-environmental properties of both clay and sand reinforced with discrete polyester fibre of length 12 mm and stabilized with chemical stabilizer RBI Grade-81. The soils were mixed with RBI Grade-81 content of 1%, 2%, 3% and 4% and fibre content of 0.25%, 0.50%, 0.75% and 1.0% of dry mass of soil for determining their individual and combined effect on different geotechnical properties. Additionally, X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) tests were also carried out to know the mineralogy and micro-structure of the hydrated products formed during the stabilization. Leachate obtained from the stabilized soils was tested for concentration of heavy metals and were found well within limits prescribed by the United States Environmental Protection Agency for hazardous waste. The results indicated that the mechanical strength parameters of the soils had significantly enhanced with the use of RBI Grade-81 and polyester fibre which was corroborated by XRD and SEM results. The clay showed higher improvement in its mechanical behaviour than that of sand. The inclusion of fibre changed the RBI Grade-81 treated soil's brittle behaviour into ductile behaviour. The results obtained were indicative of the safe and environment-friendly use of RBI Grade-81 and polyester fibre for use in road construction.