Road Construction Materials Research Articles

A study on the suitability of solid waste materials in pavement construction: A review

This paper describes the various ways in which huge volumes of waste formed from urban and semi-urban areas can be optimally reutilized as an additive in the construction of bituminous pavements. It shows that different waste materials like scrap tyres, plastic wastes, glass, coal waste, fly ash, concrete waste, wood waste, etc. can be effectively reused in bituminous pavement construction. In countries like India, waste derived from various sources is usually incinerated, open burned, dumped into water bodies, disposed through landfills or ground, and discharged to sewers. This shows the potential of waste being used as a construction material in pavement development in developing nations like India where consumption is more and the availability of space for disposal is less. Moreover, the need for effective energy utilization and global climate change have made it mandatory to reduce pollution and increase recycling and re-use. Hence, to satisfy environmental norms, such practices need to be introduced into civil engineering situations. This work evaluates the various application of solid waste in sustainable pavement engineering and reviews the existing works on the re-utilization of solid wastes as road construction material and their sustainability. Life cycle assesement (LCA) was conducted to evaluate the environmental impact of solid waste as a construction material. The principal findings of this study reveal that solid waste obtained from various sources could be effectively incorporated into construction materials in the forms of aggregate, reinforcement fiber, filler material, additive etc. In summary, the study guides us in adopting stable and eco-friendly choices of converting the wastes into superior environmentally friendly road construction materials. In addition to being a lesser burden to the environment, this practice provides a satisfactory enhancement in the strength and durability of the pavements and also helps reduce energy and overall cost thereby proving to be a very useful and effective choice for all pavement related works.

Study of the Stiffness of the Bitumen Emulsion Based Cold Recycling Mixes for Road Base Courses.

The benefits of the use of cold recycling mixtures (CRMs) in pavement rehabilitation are associated with both the reduction of natural resource consumption by replacing them with recycled materials and the reduction of energy consumption during their production and paving. The evolution of the stiffness of CRMs in road construction and the fatigue life of pavements with CRM base layers are still being investigated. In this paper, CRMs with 1% cement content, called bitumen-stabilized materials with bitumen emulsion (BSM-Es), were examined. Mixtures that were differentiated in terms of Reclaimed Asphalt Pavement (RAP) content, as well as the amount and type of bitumen emulsions, were subjected to indirect tensile stiffness modulus (ITSM) tests at 5 °C, 13 °C, and 20 °C. The thermal sensitivities of the BSM-E mixtures were analyzed. BSM-E mixture stiffness modulus levels at various temperatures were determined using a statistical approach. On the basis of the results obtained, a discussion on the mechanistic-empirical design of flexible pavements with BSM-E base layers is presented. The potential benefits of using BSM-E materials in road construction in certain aspects of pavement life are indicated.

Special-Purpose River-Port Sediment Valorization as Road Construction Material Emphasising Environmental Aspects

Abstract Special-purpose river port sediment was investigated for its potential use as a road construction material. Sediment samples were extracted from three locations in three small river ports, and detailed laboratory research was conducted to determine its basic mechanical properties and characteristics that can potentially have an adverse influence in a roadside environment. The results of the research conducted indicate that there is a need for systematic monitoring of the quality and quantity of sediment in special-purpose river ports of the Danube River Basin to maintain its mobility and prevent flooding. The basic engineering characteristics (Proctor elements, Atterberg limits, California bearing ratio, and unconfined compressive strength) determined represent the good potential of the sediment samples tested herein for use in road construction. In addition, the chemical characteristics tested indicate the need for detailed analyses of the potential environmental risk before application in civil engineering structures

Evauation of road failure along an erosion prone highway in ogun state southwestern nigeria using integrated methods

This study investigated a road failure on an erosion prone highway of Sagamu-Papalanto southwestern Nigeria. The mineralogical and chemical composition of the soils were analyzed using X-ray diffraction and X-ray fluorescence methods. The geotechnical properties of the soil such as grain size distribution, consistency limits test, specific gravity, compaction, California bearing ratio (CBR), porosity, permeability, shear strength test and cone penetrometer test were also conducted on the soil samples. The results of the investigation showed that the moisture content, specific gravity, liquid limit, plastic limits and plasticity index ranged from 9.4–18.2%; 2.54–2.58; 26.8–42.6%; 18.2–25.2% to 7.1–21.6%, respectively. Grain size distribution showed the fine and coarser fractions range from 12–32.5% to 49.4–80.5%, respectively. The maximum dry density and its optimum moisture content ranged from 1.64–1.74 g/cm3 to 12–17%, respectively. CBR results ranged from 3 to 12%. The class of subsoils namely A-26, A-7, A-2–7 (clayey soils), were identified and rendered unsuitable as road construction materials. The results from this investigation revealed that the subsoils are poor road construction materials due to its fines and plasticties. This should be put into consideration during the reconstruction and rehabilitation of the road.

Non-autoclaved foam concrete for layers of highways surface dressing

The article is devoted to the problems associated freeze with the calculated estimation of the parameters of the structural and heat-insulating antifreeze layer in the subgrade of non-rigid roads on various soil bases. The main physical, technical and deformation characteristics of monolithic dispersed non-autoclaved foam concrete reinforced with polypropylene fiber of grades of density from 600 to 1000 kg/m3 are investigated. Freezing of subsoil waters directly under the roadway pavement and, as a result, its increase in volume, leads to significant deformations of the road surface. Under such conditions, the period of defectfree operation of the roadway pavement is significantly reduced, which in turn leads to the need to repair it in a more intensive mode. One of the ways to reduce the operating cost and maintenance costs of the road transport infrastructure is to introduce into the design and construction practice new structural concepts for road surface dressing that ensure high quality pavement during the normative operational period. This can be achieved by introducing an effective heat-insulating material into the pavement structure as an anti-frost layer in order to elimi-nate the effect of frost lift of the roadway pavement of non-rigid roads. Since domestic and foreign experience freeze in the road construction has proven the effectiveness of the use of heatinsulating materials in the road surface dressing construction, in recent years in Ukraine there has been increased interest in the use of non-autoclaved foam concrete as a modern and highly effective heat-insulating material in road construction. The installation of a heat-insulating layer made of non-autoclaved foam concrete allows us to completely or partially prevent freezing or overheating of the surface dressing base, reduce the influence of periodic variations in environmental temperature, which in turn will increase the durability of the pavement structure. The publication presents nomograms for determining the optimal thickness of the heat-insulating anti-frost heavy course (layer) of road surface dressing (based on sand, loamy sand, clay and loam) done at the street and road network for all climatic and geographical regions of Ukraine.

Use of Mahua oil for rejuvenation of the aged binder through laboratory investigations

Construction industries worldwide have understood that recycling of road construction materials is vital for the sustainable development of infrastructure. However, the utilization of reclaimed asphalt pavement (RAP) material to its potential is limited to only 50%. Rejuvenators are believed to revive the aged binder's properties and provide scope for higher utilization of RAP. This paper presents an assessment of Mahua oil (biological name: Madhuca Longifolia) as a potential rejuvenator through rheological, chemical, and thermal characterization of the rejuvenated RAP binder. Based on the rheological investigations, 4 % of Mahua oil was found to be adequate to satisfy the Superpave rutting and fatigue criteria. From Thermo Gravimetric Analysis (TGA), the rejuvenator was found to be stable up to 220 °C. Fourier Transform Infrared Spectroscopy (FTIR) showed a decline in the carbonyl index and sulfoxide index in the rejuvenated binder, which indicates the revitalization of the primary characteristics of the binder. Outcomes of the study indicate that Mahua oil can improve the rheological thermal and chemical properties of the aged binder.

Strength Development of Geopolymer Composites Made from Red Mud–Fly Ash as a Subgrade Material in Road Construction

Abstract The application of industrial waste in construction reduces the dependency on natural resources. The materials, including red mud (RM) and fly ash (FA), proved to be favorable materials. H...

Effects of pyrolysis temperature and reaction time on the performance of swine-manure-derived bio-binder

Swine-manure-derived bio-binder can solve the problem of environmental pollution caused by the accumulation of solid waste from swine manure, and realize the replacement of asphalt by sustainable road construction materials. The main purpose of this study is to study the influence of pyrolysis conditions on the performance of swine-manure-derived bio-binder, the swine manure particles were cracked at 5 pyrolysis temperatures and 2 reaction times. Ten kinds of swine-manure-derived bio-oil were prepared, and 15% bio-oil were used to partially replace petroleum asphalt to prepare corresponding bio-binder. The effects of pyrolysis conditions on the penetration, softening point, ductility, water absorption and the rheological properties of bio-binder were tested. The results show that the maximum bio-oil yield of 1 s reaction time at 550 °C pyrolysis temperature was 45.1%. The high temperature stability of bio-binder is better than that of virgin asphalt. The high temperature stability of bio-binder gradually decreases with the pyrolysis temperature and reaction time of bio-oil. The fatigue performance and low-temperature crack resistance of the bio-binder are poorer than that of virgin asphalt on the low pyrolysis temperature, but those performances will be gradually improved with the pyrolysis temperature. The low-temperature crack resistance of the binder can be improved by prolonging the cracking reaction time under a certain pyrolysis temperature. Considering the yield of bio-oil and the performance of bio-binder comprehensively, the swine-manure-derived bio-oil at a pyrolysis temperature of 550 °C and a reaction time of 1 s is the most suitable for the preparation of bio-binder.

Selection of effective material for road construction

The object of research is the technology of road surface construction using alternative materials and the possibility of introducing automated systems to increase productivity. The main hypothesis of the study lies in the found alternative material, with the help of which it is possible to reduce the cost of road construction and increase the quality and service life. To reduce the cost of roads, it is necessary to create new construction technologies using innovative or alternative materials, use the latest mechanisms and introduce automated and robotic systems. This can be achieved if to carefully study the technology of the construction process device. One of the materials of the road surface is crushed stone, gravel and sand. Let’s consider as one of the alternative options for mining waste – crushed slag. When determining the main physical and mechanical properties of crushed slag, the standard method for testing crushed stone in stationary laboratory conditions was used. In the course of the study, the methods of system analysis and generalization were used, as well as the method of material testing. The authors of the work analyzed the technological processes of road construction and proposed a material based on the test results – crushed slag from a ferroalloy plant. During the tests, it was confirmed that the material is an alternative quarry crushed stone. Ferroalloy crushed stone has the same field of application, strength, density, frost resistance, but the cost is an order of magnitude less than a ton, creates an economic effect of 31.93 USD per ton. This makes it possible to reduce the cost of the road surface and ensures the quality that meets the regulatory requirements, and the production of modern technologies will reduce the time standard at some construction sites. When testing crushed slag, the results obtained confirm that this material meets all the requirements and may well replace granite crushed stone in the construction of roads for various purposes. Such material can be used not only in Ukraine, but also in countries with similar requirements for the composition of the roadway.

Use Of Tondon Marante Coarse Aggregate For Mixed HRS-BASE and Mixed AC-BC

The availability of road construction materials matching the design criteria and mixed features in terms of reliability is one of the success factors in road construction. The goal of this study is to understand whether Tondon Marante coarse aggregate in Hot Rolled Sheet Binder-Course mix and in Asphalt Concrete Binder-Course mixture can be used as flexible pavement road material. This study was carried out by measuring the characteristic of Marshal using penetration asphalt 60/70 for Hot Rolled Sheet Binder-Course mixture on asphalt content variation of 6 percent, 6.5 percent, 7 percent, 7.5 percent, 8 percent and for Asphalt Concrete Binder-Course mixture on bitumen content variation of 5 percent, 5.5 percent, 6.5 percent, 6.5 percent, 7 percent according to Asphalt Concrete Binder-Course mixture on bitumen content variation. The results showed that Hot Rolled Sheet Binder-Course mixture's optimum asphalt content was 7 percent with a VIM value of 4.78 percent, VFB 74.32 percent, VMA 18.37 percent, Stability 894.83 kg, Flow 3.32 mm, MQ 269.22 kg / mm and 24 hours immersion index 94.05 percent, and Asphalt Concrete Binder-Course mixture's optimum asphalt content is 6.5 percent with a VIM value of 3.83 percent. It is concluded that Tondon Marante coarse aggregate can be used as a versatile pavement road material in a mixture of Hot Rolled Sheet Binder-Course and Asphalt Concrete Binder-Course mix, based on the Marshal characteristic test that primarily meets the general specification of Bina Marga 2010 Revision 3 (Division 6) 'Asphalt Pavement'.

Effect of Elapsed Time after Mixing on the Strength Properties of Lime–Iron Ore Tailings Treated Black Cotton Soil as a Road Construction Material

The study evaluated the effect of elapsed time after mixing on the strength properties of lime and iron ore tailings (IOT) treated black cotton soil (BCS) (an expansive tropical black clay) as road construction material. BCS was treated with 0, 2, 4, 6, and 8% lime and 0, 2, 4, 6, 8, and 10% IOT content by dry weight of soil. Tests carried out include Atterberg limits, compaction, unconfined compressive strength (UCS), California bearing ratio (CBR) (unsoaked condition), and microstructure of specimens. Statistical analysis was done using MINI-TAB software. Results show that the liquid limit (LL) of BCS–lime–IOT mixtures decreased with increase in lime and IOT content. The LL values of all the treated BCS increased between 0 and 1 h elapsed time after mixing. On the other hand, the plastic limit (PL) of BCS decreased with increase in lime and IOT content while the plasticity index (PI) decreased from 27.7 to 22.9% for 0% lime/0% IOT content and from 30.6 to 26.6% for 0% lime/10% IOT content. Maximum dry density (MDD) of BCS increased while optimum moisture content (OMC) decreased with higher IOT content. The natural BCS recorded OMC value of 25.6% decreased to 15.2% for 8% lime/10% IOT treatment. The strength (i.e., UCS and CBR values) increased with increase in lime/IOT contents between 0 and 2 h elapsed time after mixing. Peak values were recorded for 8% lime/8% IOT treatment for all lime content considered. Regression analysis shows a strong relationship between the strength properties and the soil parameters. An optimal 8% lime/8% IOT treatment of BCS for elapsed time after mixing not exceeding 2 h was established and is recommended as sub-base material for low-trafficked roads.

A Review of the Utilisation of Recycled Waste Material as an Alternative Modifier in Asphalt Mixtures

The possibility of using waste materials in road construction is of great interest as their utilisation may contribute to reducing the problems of hazard and pollution and conserve natural resources. Thus, there is an urgent need to find a sustainable method for using waste materials as a substitute in the standard asphalt binders. There are several concerns about the physical and chemical properties and mechanical performance of asphalt pavements incorporated with waste material in the effort to reduce permanent deformation of the road surface. This review article presents a brief discussion of the asphalt mixtures modified with waste material, and the recycled materials used as a modifier in the asphalt mixture. The present paper summarises the use of crumb rubber, crushed concrete, steel slag, glass fibre and plastic waste in asphalt mixtures. The use of waste materials as a modifier in asphalt mixture resulted in improved asphalt pavement performance. Results advocate that rubberised asphalt mixture with desired properties can be designed as an additive with a friendly environmental approach in construction materials. The researches that adopted the influence of usage, recycle waste material to improve the performance of the asphalt of the road are still limited compared to other construction fields. Doi: 10.28991/cej-2020-SP(EMCE)-05 Full Text: PDF

Semi-automatic Extraction of Rural Roads From High-Resolution Remote Sensing Images Based on a Multifeature Combination

Roads play a vital role in rural economic development. However, rural roads feature irregular curvature changes, are narrow, and are built using diverse construction materials, which renders the analysis of road geometric and spectral characteristics less certain and reduces the automation ability of existing methods. Thus, this letter proposes a semiautomatic extraction of rural roads from high-resolution remote sensing images based on a multifeature combination. First, to address irregular curvature change characteristics of rural roads, we modify multiscale line segment orientation histogram (MLSOH) descriptors to reduce the impact of local curvature change on tracking. Second, we design a multicircle template to analyze the contrast between roads and nonroads and solve the problem of narrow roads. Last, we propose a panchromatic and hue, saturation, value (HSV) space interactive matching model to solve the problem of matching diverse road construction materials. This letter employs Pleiades satellite and GF-2 imagery. Compared with other methods, the proposed method improves automated road extraction by ensuring the extraction accuracy.

EXPERIMENTAL STUDY ON APPLICATION OF MARBLE WASTE AS CONVENTIONAL AGGREGATE FOR BASE COURSE MATERIALS

Recently, highway and construction industries utilize a substantial quantity of conventional aggregates. The increasing demands for conventional aggregate cause an increase in the cost of construction, reduction of natural resource, and continuing deterioration of the earth's surface. On the other hand, the waste generated from the marble industries during the process of cutting and polishing was increasing day by day all over the world. In Ethiopia, the use of Marble Waste Aggregate materials in road construction as a base course material was not well-known, and it was simply wasted at every place where the marble production was continuing. Therefore, this paper focused on evaluating the possibility of using marble waste aggregate as conventional aggregate in the base course layer of flexible pavements by experimental method. To achieve the objectives of the research, mechanical stabilization and laboratory tests have been carried out at different percentage replacement of Conventional Aggregate by (0%, 20%, 40%, 50%, 60%, 80%, and 100%) of Marble Waste Aggregate weights. Marble wastes materials are collected from Burayyu city, Alisha marble processing industry. The laboratory test results for MWA indicated SG, ACV, AIV, LAA, Flakiness Index , Elongation Index, Plastic Index, Water Absorption, and CBR of 2.74%, 23.63%, 26.21%, 27.03%, 26.48%, 13.29%, Non Plastic, 0.50% and 73.3%, respectively. These test results fulfilled the ERA standard specification for some tests, and it showed marginal quality values to the standard specification for GB2 and GB3 base course materials. CBR and gradation test results shown failure to meet the standard specification. Thus, mechanical stabilization was done to improve the mechanical and physical properties of Marble Waste Aggregate. Blending of 80%MWA with 20% CA results in SG, ACV, AIV, LAA, Flakiness Index, Elongation Index, Plastic Index, Water Absorption, and CBR of 2.83%, 18.2%, 21.52%, 22.58%, 23.79%, 16.29%, Non Plastic, 0.80%,and 82.5% respectively. At this proportion the gradation also observed to fit with the required ERA standard specification of GB2 and GB3 materials. Therefore, the use of marble waste aggregate up to 80% by weight is recommended for road base course layer, when it is found near to the construction site and in places where the materials are abundantly available.

Utilization of Lignin from the Waste of Bioethanol Production as a Mortar Additive

Lignin is the second most abundant biopolymer, exceeded only by cellulose, and comprises 15-25% of the dry weight of woody plants, with around 285,000 tons/year of production capacity globally. This study aims to utilize the lignin obtained from the waste of bioethanol production from oil palm empty fruit bunches (OPEFB) as a mortar additive. The use of mortar as a material for road construction is increasing, but its long time hardening is causing problems such as traffic jams. Lignin can be used as an additive to shorten the hardening time of mortar. Lignin was isolated at various NaOH concentrations and temperatures of OPEFB pretreatment for bioethanol production. The workability of the slump and compressive strength of mortars generated were further tested. Lignin from OPEFB can be used as a water reducer in the mortar with improved workability as much as 24.4% compared to controls. The addition of lignin could also increase the compressive strength at the mortar age of 7 and 28 days compared to the commercial lignosulfonate and control on the various water-cement ratios. The setting time of mortar with the lignin addition increased rapidly, reaching up to 80% at the 7 days, indicating that curing time is getting shorter. The most remarkable improvement of compressive strength with suitable workability and high-quality concrete was reached by 1% lignin addition and 0.45 water-cement ratio with compressive strength 38.81 N/mm2 at 28 days.Keywords: compressive strength, lignin, mortar, OPEFB, water reducer

Sustainable Reuse of Coal Mine Waste: Experimental and Economic Assessments for Embankments and Pavement Layer Applications in Morocco

This paper deals with the potential reuse of coal mine waste rocks (CMWR) as an alternative material for road construction to conserve the natural resources and sustainable management of mining waste. The investigation was conducted through the determination of the chemical, mineralogical, geotechnical properties, and acid mine drainage formulation of CMWR as well as economic feasibility. This waste was used either alone for embankments and mixed with stabilizing agents fly ash (FA) and hydraulic road binder (HRB) for pavement applications. The experimental results confirmed that weathered CMWR can be successfully used alone as a sustainable alternative material for the embankment. Furthermore, the use of stabilizing agents in the following ratio CMWR:FA:HRB = 80:20:5 allow the use of CMWR in road sub-base layers for high-traffic pavements. Also, the environmental investigations showed that CMWR does not present any potential contaminating risk on the surrounding environment and most of the pyrite particles were already oxidized. Therefore, the environmental impact of acid mine drainage produced by pyritic waste throughout its life cycle can be neglected. Finally, an economic case study confirmed the workability of CMWR reuse in a radius of 29 km around their dumps by resulting in a lower cost compared with conventional materials.

Strength enhancement in high silica wood ash stabilized lateritic soil using sodium tetraoxosulphate VI (Na2SO4) as activator

Strength enhancement of waste wood ash (WWA) stabilized lateritic soil, classified as A-7-5(11) and ML (silt), was investigated using sodium sulphate (Na2SO4) as an activator. Basic laboratory geotechnical tests for assessing compacted soil as road construction material were carried out on the samples prepared by admixing the lateritic soil with the predetermined percentages of WWA and Na2SO4 relative to the mass of the soil. The results showed reductions in the percentage of fines as both WWA and Na2SO4 contents increased. Liquid and plastic limits of the lateritic soil increased with the increasing contents of both WWA and Na2SO4, and this led to reduction of the plasticity index and hence improved the workability of the soil. The maximum dry density (MDD) of soil increased with corresponding decrease in optimum moisture content (OMC) as the percentage of Na2SO4 increased. However, MDD increased up to 3% WWA and thereafter decreased. OMC decreased at 3% WWA and then increased with increasing content of WWA. The California bearing ratio increased with increasing contents of WWA but with pronounced increment at 4% Na2SO4. Satisfactory performance of the lateritic soil was observed with up to 9% WWA and 4% Na2SO4 activation, at which the soil could be used as road subgrade material

Coal mining and the environmental impact of Acid Mine Drainage(AMD): A review

In spite of the growing global initiatives towards achieving clean energy, coal remains a dominant source of electricity generation, a fuel for iron and steel production, an important entity among road construction materials and a commodity for foreign exchange earnings for many nations. Coal mining from old and active sites remains a source of an environmental problem described as acid mine drainage (AMD). AMD is produced when sulfide present in waste rocks or tailings in coal mines reacts with air and water in a microbes facilitated oxidation to form solutions with high acidity. The acids formed by these chemical and biological conditions further release heavy metals present in the host rock in concentrations higher than are acceptable by environmental standards (pb;0.01, Zn;5, Cu;2, Fe;0.3 mg/l as prescribed by WHO and Encyclopedia of Environmental Science,2000) such that soils, surface and underground waters are contaminated. Consequently, the human population which derives her livelihood in the mine zones, in form of crop production and fishing/modern aquaculture is endangered by terminal health diseases. This article aims at bringing forth, the urgent need to work towards achieving goal six of the United Nations Sustainable Development Goals, 2030 (SDGs-6) which is clean water and sanitation while enriching the knowledge repository of the environmental problem for the purpose of teaching, research, community services and policy making. An overview of AMD menace, variables which influence its formation, selected areas that have been impacted, and a brief analysis of its treatment cost have been discussed with a list of concluding remarks in the paper.
 Keywords: Coal, Mining, Environmental , AMD

Stabilization of Black Cotton Soil by Using GGBS, Lime and Nano-Silica

Soil is known of their geotechnical properties and suitability as base, sub-based and sub-grade materials for road construction with the increase in population reduce the land availability. In current situation there is increasingly more development of structures and other structural building structures must be completed on less strength or poor soil. Black cotton soil is found in Madhya Pradesh, Karnataka, Maharashtra Andhra Pradesh & Tamilnadu covering an area of about 3.0 lakh sq. km in our nation. Black cotton soil is one of the largest soil stores of India, so for the reason need to increase its geotechnical properties and make it comfortable for the development reason. In pavement surface causes problems like cracking, rutting, patching, potholes and detoriation in the pavement surface. The development on black cotton soil (expansive soil) has consistently been a giving tough task for the specialists as the Road & structure laying on black cotton soil breaks without any notice. Stabilization of soil by GGBS couldn't just take care of the issue of appropriate stabilization of black cotton soil, yet in addition settle the issue of removal of a modern waste for example GGBS. The properties of black cotton soil can be modified by stabilizing the soil with the use of additives or stabilizers like Lime (6%), GGBS (30%) & Nano silica (0.3%, 0.6% & 0.9%). There is increase in various geotechnical properties like liquid limit, and plastic limit, compaction characteristics, unconfined compressive strength, CBR values and swelling pressure were determined. An experimental investigation is carried out to study the influence of admixture in soil with respect to the strength characteristics. In this comparative study laboratory tests such as Atterberg’s limit, Compaction test, swelling index and California Bearing Ratio (CBR)& Unconfined compressive strength (UCS)test were carried out for black cotton soil.

Analysis of Major Environmental Impact Categories of Road Construction Materials

To address the environmental problems associated with construction materials, the construction industry has made considerable efforts to reduce carbon emissions. However, construction materials cause several other environmental problems in addition to carbon emissions and thus, a comprehensive analysis of environmental impact categories is required. This study aims to determine the major environmental impact categories for each construction material in production stage using the life cycle assessment (LCA) technique on road projects. Through the review of life cycle impact assessment (LCIA) methodologies, the abiotic depletion potential (ADP), ozone depletion potential, photochemical oxidant creation potential, acidification potential, eutrophication potential, eco-toxicity potential, human toxicity potential, as well as the global warming potential (GWP) were defined as impact categories. To define the impact categories for road construction materials, major environmental pollutants were analyzed for a number of road projects, and impact categories for 13 major construction materials were selected as mandatory impact categories. These materials contributed more than 80% to the impact categories from an LCA perspective. The impact categories to which each material contributed more than 99% were proposed as specialization impact categories to provide basic data for use in the LCIA of future road projects.