Indirect Tensile Strength Ratio Research Articles

Assessing the influence of nano graphene oxide application in mitigating the adverse effects of runoff pH on the moisture susceptibility of asphalt concretes

The specifications of runoff entered the pavement has an essential role in the severity of moisture damage of asphalt concretes. Changing the pH of runoff has a negative impact on moisture damage and intensifies this damage in asphalt concretes. Accordingly, in this study, the impact of nanographene oxide (NGO) as a contaminant adsorbent and bitumen modified to decrease the destructive impacts of acidity changes in runoff has been investigated. For this purpose, limestone and siliceous aggregates, PG 64–16 bitumen, and NGO in two different contents (0.3 % and 0.5 % of the weight of bitumen) were utilized. To asses the strength of asphalt concretes with different runoff pH conditions, hydrochloric acid and sodium oxide were used to simulate acidic and basic runoffs, respectively. The indirect tensile strength (ITS) of asphalt concretes in different environmental states was tested to compare the severity of moisture sensitivity. Moreover, the surface free energy (SFE) elements of bitumen and aggregates were calculated utilizing the Wilhelmy Plate (WP) and the Universal Sorption Device (USD), respectively. The parameters of SFE theory were used to assess the mechanisms of water damage potential. The SFE results showed that NGO decreased the debonding energy (DE) of the mixtures. Changes in DE in neutral environments were minor, but with the polarization of environmental conditions, especially in basic states, these changes intensified. The application of NGO improved the total bitumen SFE, which reduced the possibility of moisture sensitivity as a cohesive failure. The results of mechanical methods indicated that the use of NGO in specimens with limestone and siliceous aggregate increased the indirect tensile strength ratio (TSR) in moisture conditions with different degrees of acidity. The mechanical experiment results also confirmed the SFE method's results that the effect of using NGO on increasing the TSR index at pH equal to 7 was minor, and it was intensified in acidic and basic waters.

Optimal design of mechanical performances of asphalt mixtures comprising nano-clay additives

Abstract To sustain the life of flexible pavement materials, the quality of the binder needs to be modified and improved. The purpose of the current research is to investigate the optimum mechanical performances, Marshall characteristics, and moisture damages of hot asphalt mixtures containing nano-clay (nC) additives. Three nominated contents of nC additives of 3, 5, and 7% of the hot asphalt weight were combined by a shear blender at 4,000 rpm for 45 min at 150 ± 5°C. Significant mechanical tests were carried out to estimate the modified asphalt mixture characteristics, such as Marshall stability and moisture susceptibility. Mechanical test results showed that the use of nC as an additive was suitable for enhancing the main characteristics of hot asphalt mixes. Generally, it was found that the indirect tensile strength ratio and stability values of the asphalt mixtures containing 3, 5, and 7% of nC were improved by 8, 23, and 24% and 12.5, 40, and 52%, respectively. The 7% nano-clay additive showed superior values of tensile strength and stability as compared with all asphalt mixtures (i.e., 94% and 15.8 kN, respectively).

Investigation of Performance Properties of Milled Carbon Fiber Reinforced Hot Mix Asphalt

In this study, the mechanical behavior and resistance to moisture damage of hot mix asphalt (HMA) concrete with the addition of Milled Carbon Fiber (MCF) were experimentally investigated. For this purpose, the gradation curve within the boundaries of the Turkish highway construction specifications (HTS) has been determined. By keeping the determined gradation constant, MCF was added at different rates (1 %, 1.5 %, 2 %, 2.5 %, 3 %) by weight of the mixture. In the study, first, optimum bitumen ratios (OBR) of pure control samples (0 %-Control) without MCF and mixtures with MCF additives were determined by using the Marshall design method. To determine the OBR, samples were prepared with bitumen content of 3.5 %, 4 %, 4.5 %, 5 %, 5.5 %, and 6 % at each carbon additive ratio. The mixture samples prepared using the specified OBRs were subjected to Marshall stability (MS) and flow, as well as to retained Marshall stability (RMS), indirect tensile strength (ITS), and moisture damage resistance tests. According to the test results, it was observed that the MS values of the asphalt concrete with MCF additives increased at certain carbon additive ratios, while the flow values decreased compared to the witness sample. It was determined that the RMS and indirect tensile strength ratio (TSR) values of hot mixes with MCF-added bitumen increased and the moisture damage resistance of the mixes increased. As a result, when the optimum MCF ratio determined for the wearing course is used, it is thought that the engineering properties of HMA will improve.

Performance evolution of novel palm leaf powder used for enhancing hot mix asphalt

Abstract Recently, researchers have been moving toward using local waste as an alternative for construction materials. Using these wastes to pave roads is one of the essential recycling methods, which aims to reduce the consumption of natural resources and environmental pollution resulting from the difficulty of decomposing these wastes. In the Middle East, especially in Iraq, Date Palm fiber is widely available as a local waste material. The aim of this research is to evaluate the performance of a developed asphalt mixture with palm leaf powder (PLP) as a partially substituted mineral filler. The Marshall mix design method produced the asphaltic mixes with ordinary Portland cement and PLP as mineral fillers. PLP was included in three rates denoted by 10, 20, and 30% by the weight of the mineral filler. Marshal stability, flow, bulk specific gravity, air voids, voids in mineral aggregates, voids filled with the binder, the indirect tensile strength, and the indirect tensile strength ratio of the PLP mixture were measured and compared with those of the conventional asphalt mixture. Based on the findings of this study, 20% of the Portland cement could be replaced with PLP, at which all of the properties of the enhanced mixture met the requirements of the Iraqi specifications. Then, the asphalt mix with 20% PLP was tested to assess its resistance against fatigue cracks. The results support the usage of waste PLP in pavement construction, enhancing its properties, which would also be very effective as an eco-friendly material.

Evaluation of the Mechanical Performance of Warm Bio-Recycled Asphalt Mixtures

Currently, approximately 90% of road pavement mixtures are derived from fossil fuels, a major source of the greenhouse gases contributing to global warming. This fact, together with the scarcity of raw materials in pavement engineering, has prompted recent investigations into sustainable alternatives. Biobinders, serving as substitutes or modifiers for petroleum-based asphalt binders, have gained attention, alongside the integration of recycled materials in recycled asphalt (RA). This study addresses these concerns by combining three techniques: (1) substituting a bitumen-based binder with a biobinder; (2) incorporating a high RA percentage (>30%); and (3) manufacturing the asphalt mixture at a reduced temperature (140 °C). These approaches result in the production and evaluation of warm bio-recycled asphalt mixtures. Materials were assessed at both the binder and mixture levels. The control binder, RA binder, and biobinder underwent conventional and rheological characterization. In terms of mixtures, warm bio-recycled asphalt mixtures employed a biobinder as the only virgin binder, with RA contents of 50% and 70%. Mechanical characterization focused on bearing capacity, cohesion, permanent deformations, and moisture damage. The warm bio-recycled asphalt mixtures exhibited adequate outcomes in bearing capacity through the stiffness modulus being 18,120 MPa and 15,683 MPa for bio-recycled asphalt with 50% RA and bio-recycled asphalt with 70% RA, respectively. Bio-recycled asphalt with 50% RA and bio-recycled asphalt with 70% RA showed low permanent deformation percentages, specifically 0.5% and 0.7%, respectively, in comparison to the reference recycled asphalt mixture with 1.5%, allaying concerns in practical applications due to the biobinder’s soft consistency. The bio-recycled asphalt mixture with 70% RA displayed good mechanical performance regarding the studied mechanical characterization, especially exhibiting the least susceptibility to water-induced damage with 97% of the retained indirect tensile strength ratio, addressing concerns related to moisture damage in warm asphalt mixtures with high RA content and biobinders. These findings offer valuable insights into the adoption of more sustainable practices in the asphalt pavement industry, reducing the concerns associated with warm bio-recycled asphalt mixtures.

Assessment of Traditional Asphalt Mixture Performance Using Natural Asphalt from Sulfur Springs

This research utilized natural asphalt (NA) deposits from sulfur springs in western Iraq. Laboratory tests were conducted to evaluate the performance of an asphalt mixture incorporating NA and verify its suitability for local pavement applications. To achieve this, a combination of two types of NA, namely soft SNA and hard HNA, was blended to create a binder known as Type HSNA. The resulting HSNA exhibited a penetration grade that adhered to Iraqi specifications. Various percentages of NA (20%, 40%, 60%, and 80%) were added to petroleum asphalt. The findings revealed enhanced physical properties of HSNA, which also satisfied the requirements outlined in the Iraqi specifications for asphalt cement. Consequently, HSNA can serve as an asphalt binder to produce asphalt mixtures for flexible paving construction. Notably, HSNA mixtures exhibited greater Marshall stability and stiffness index when compared to traditional mixtures. The results from indirect tensile strength (ITS) and tensile strength ratio (TSR) tests indicated that the 80NA mixture displayed the highest ITS values and a TSR of 81.36%, surpassing the TSR of the mixture incorporating petroleum asphalt by 0.57%.

Preliminary assessment of the properties of composite layers based on porous asphalt and coloured mortar

The paper presents the results of the properties of composite layers made of porous asphalt, with a void content above 30%, filled with a special-coloured mortar. Three mortars of white, red and blue colours were selected, whose compressive strength after 2 days was over 60 MPa and the flexural strength was over 7 MPa. The study of composite layer aimed at determination of the water sensitivity expressed in ITSR (Indirect Tensile Strength Ratio) according to the standard EN 12697-12 (method A) and rutting resistance according to standard EN 12697-22 in the small apparatus (method B). The results indicate that such solutions will be justified in places with extremely heavy traffic, such as bus stops. In addition, the condition of the layer surface after simulating its wear was assessed using of the CTM (Circular Track Meter), the BPT (British Pendulum Tester) and a reflectometer. The results indicate that they can be used in areas with low speed limits. On the other hand, the possibility of introducing the pigment into the mortar has a positive effect on surface of those elements of the communication system, which should have a different color than the road surface. These are the surfaces of bicycle paths, pedestrian and bicycle routes, areas of intersections, where their visibility plays an important role due to the safety of users.

Laboratory Study of Asphalt Concrete for Base Course with Reclaimed Asphalt, Recycling Agents, and Jute Fibres

The way we treat materials after their lifespan is changing. We are finding a new, more effective way to deal with waste: using it, rather than depositing it in landfills. Since bitumen mixtures are the most popular paving materials by far, and their lifespan is limited, there is a constant availability of old asphalt pavement or reclaimed asphalt (RA). To restore the aged binder properties, we can use recycling agents. In this study, two commercialized biobased recycling agents were used. Furthermore, jute fibers were used as a reinforcement. The influence of the different fiber content and fiber length was investigated in mixtures without the recycling agents. In addition, alkali-treated fibers were used in some mixes for better fiber compatibility with the bitumen matrix. Air voids content, moisture, freeze–thaw susceptibility, stiffness modulus (IT-CY), resistance to crack propagation, and complex modulus tests were conducted. The addition of recycling agents led to a decrease in stiffness. A lower indirect tensile strength ratio (ITSR), increased stiffness, and best crack propagation results were recorded in some mixtures with fibers and recycling agents.

Comparison of the moisture resistance of a steel-slag stone mastic asphalt mixture modified with Ca(OH)2

Stone mastic asphalt is a type of hot mix asphalt that requires much coarse aggregate, so substitution waste aggregate, such as steel slag, will be an economic reason. The problem is that there are still many things that have not been consistent in various studies related to the moisture resistance of steel slag. The study aimed to compare the effect of Ca(OH)2 on the moisture resistance of the steel-slag stone mastic asphalt mixture and to determine the optimal Ca(OH)2 dosage for improving the mixture resistance. This study employs basalt aggregate, steel slag from Krakatau Steel Company, 60/70 penetration asphalt, a stabilizing substance made of bamboo fiber, and Ca(OH)2. The Texas boiling and the static immersed methods are used to test the adhesion on a loose mixture. The retained Marshall stability and indirect tensile strength are used to test the adhesion on the compacted mix. Testing result of Krakatau steel slag shows that steel slag has a much higher Fe2O3 content than steel slag in general and has low water absorption; a poor affinity for asphalt results from this. The result of the Texas boiling method showed a decrease in the percentage adhesion value between steel slag and asphalt compared to natural basalt aggregates and asphalt. Marshall Stability Ratio and Tensile Strength Ratio increased after mixing the asphalt with Ca(OH)2. Marshall test results show decreased stability in mixtures with steel slag substitution. Adding Ca(OH)2 increased stability and resistance to moisture significantly. This indicated that Ca(OH)2 enhances moisture resistance on stone mastic asphalt with modified steel slag. Stability, Marshall stability ratio, indirect tensile strength ratio, particle loss, and Texas boiling test significantly improved with adding Ca(OH)2

Performance evaluation of WMA mixtures with RAP

Nowadays, asphalt industries are seeking for new methodologies in order to minimize global warming and emission of greenhouse gases. One of the solutions found out was the use of warm mix asphalt (WMA) technology which allows reduction in asphalt mixing, working and compaction temperature. WMA reduces the desired temperature in comparison with hot mix asphalt by 20–40°C. In addition to this issue, the lack of superior quality natural aggregate resources everywhere around the world, it is essential to use the available natural resources efficiently along with the available construction and demolition waste such as recycled asphalt pavement (RAP) if possible, without compromising in the performance of the mixtures. In this study, reclaimed asphalt pavement was used as partial replacement for conventional aggregates and binder. The RAP contents of 0%, 25% and 50% were considered. Zycotherm was used as warm mix additive which improves the pavement moisture resistance by serving as an anti-stripping agent. The mixtures were prepared with HMA @ 130°C, HMA @ 160°C, WMA @ 130°C and all these three mixtures with partial replacement with RAP. The RAP material with 0, 25 and 50% replacement was adopted for both HMA and WMA for DBM grade 2 course. Zycotherm was added by 0.1% by weight of binder in both HMA and WMA mixes. The prepared test specimens were tested for Marshall and indirect tensile strength (ITS) test. The test results indicated that the WMA blend prepared using 0.1% by the weight of binder content showed good results compared to the hot mix asphalt @ 130°C. The indirect tensile strength ratio (TSR) of mixes containing RAP is found to be higher when compared to the mixes without RAP indicating lower moisture susceptibility of the mixtures. This study demonstrated the possible use of RAP in WMA mixes with better performance than HMA.

Assessment of Waste Glass Incorporation in Asphalt Concrete for Surface Layer Construction.

The growing need to preserve natural resources and minimize landfill waste has led to an increased consideration of incorporating waste materials in road construction and maintenance. This study focuses specifically on utilizing waste glass as part of the aggregates in hot asphalt, particularly in Asphalt Concrete (AC) for surface layers, known as "Glassphalt". Glass, due to its poor adhesion to bitumen, presents challenges when used in asphalt mixtures. Two types of waste glass, monolithic and tempered, were incorporated at two distinct contents, 10% and 15%, into the AC. Several properties such as stiffness, resistance to permanent deformation (evaluated through cyclic compression tests), indirect tensile strength, and the indirect tensile strength ratio (ITSR) were assessed for all Glassphalt mixtures, as well as the conventional mixture. Additionally, the Solar Reflectance Index (SRI) was measured to evaluate the reflectivity of the resulting Glassphalts. The findings indicate that the incorporation of both types of waste glass resulted in reduced stiffness and resistance to permanent deformation. Regarding water sensitivity (ITSR), the Glassphalts containing 15% waste glass, regardless of the glass type, exhibited ITSR values below the accepted threshold of 80%. The addition of waste glass did not yield significant changes in SRI measurements.

Experimental Analysis to Evaluate the Impact of Styrene-Butadiene-Styrene and Crumb Rubber on the Rutting and Moisture Resistance of Asphalt Mixtures

The most severe distresses in asphalt pavement are rutting, fatigue, and low-temperature cracking; therefore, to solve these problems, it is essential to modify asphalt binders in asphalt concrete mixtures. In this study, a comparison between using styrene-butadiene-styrene (SBS) and crumb rubber (CR) as modifiers for asphalt binders to overcome distress issues was conducted. Base and SBS or CR-modified binders were subjected to all conventional and Superpave binder tests. Engineering tests such as the Hamburg wheel tracker and indirect tensile strength ratio were also run to evaluate the engineering properties. The used SBS percentages were 1, 2, 3, 4, and 5%, while CR percentages were 3, 6, 9, 12, and 15% by total weight. The results showed lower penetration, higher softening point, viscosity, and elastic recovery for both additives. In addition, dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests showed increasing values of both high and low temperatures of modified asphalt performance grade (PG) with increasing SBS or CR percent. The tensile strength ratio and Hamburg wheel tracker results showed the best engineering properties at 3% SBS or 9% CR, the optimum percent. A triple percentage of CR is needed to get the same effect of SBS for the asphalt mixture.

Improvement of Engineering Properties of Asphalt Binder and Mixture by Using SBS Additive Material

Rutting, thermal cracking, and stripping are among the most severe distress types in asphalt pavement. In this study, a specified type of styrene-butadiene-styrene (SBS) was used as a modifier for a low viscosity asphalt binder G80/100 (PG 58-22) to overcome the issues of the distresses in the asphalt mixture. The mixing process had been evaluated by using fluorescent microscopy. The control- and SBS-modified binders were subjected to all conventional and Superpave binder tests. The Hamburg wheel tracker (HWT) and indirect tensile strength ratio (ITSR) tests were conducted to evaluate the engineering properties of the control and modified asphalt mixtures. The used SBS percentages were 1, 2, 3, 4, and 5% of the total weight of the binder. The results showed lower penetration, higher softening point, viscosity, and elastic recovery. The dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests showed an increasing SBS% leading to an increase in both values of high and low temperatures of the asphalt performance grade (PG). The tensile strength ratio and Hamburg wheel tracker tests’ results showed that the highest TSR and rutting parameter values were obtained at 3% SBS, which was the optimum SBS content for the asphalt mixture and the resulted modified asphalt is PG76-16.

Contribution to the Research on the Application of Bio-Ash as a Filler in Asphalt Mixtures

The intensive construction of all categories of roads and the very demanding maintenance of the pavement structures of existing roads due to ever-increasing traffic loads confronts us with a lack of resources and also an increase in cost for the constituent materials of asphalt mixtures. On the other hand, there is another problem: large amounts of waste material in the form of bio-ash, which is obtained by burning waste wood biomass in the production of thermal energy and/or electricity. In order to solve the environmental problem of bio-ash disposal, research was conducted on the use of waste bio-ash as a constituent material in asphalt pavements. As part of this study, the effect of asphalt concrete mix, with bio-ash as a filler, on the release of harmful substances into the environment was investigated. The possibility of using wood bio-ash (BA) as a filler in asphalt mixtures was then determined through physical and mechanical property tests. The properties of the asphalt sample’s sensitivity to the action of water (indirect tensile strength ratio—ITSR) and resistance to rutting were tested for asphalt concrete type AC 11 surf with 50% bio-ash in the filler. It was established that asphalt concrete does not release harmful substances into the environment and that the 50% share of bio-ash in the filler results in asphalt that has good resistance to water sensitivity and even greater resistance to rutting.

Impact of curing on the volumetric and mechanical properties of cold bitumen emulsion mix

Cold bitumen emulsion mix (CBEM) is an emerging sustainable material for constructing the base or surface layer of flexible pavements, reducing energy consumption and global warming effects compared to hot mix asphalt. The main challenges associated with CBEM are low initial strength, moisture susceptibility, etc. This is primarily due to water encapsulation. The curing process allows the water to evaporate gradually over time, improving mechanical properties. This study investigates CBEM’s volumetric and mechanical properties under different curing conditions. CBEMs were prepared using low (50 blows) and high (75 blows) compaction efforts and cured at 25, 40, and 55 °C for 1 to 28 days. In volumetric characteristics, the air voids and voids in mineral aggregates decreased slightly with curing, while total binder volume decreased. Effective binder volume and voids filled with binder increased slightly, then decreased. The mechanical properties, i.e., Marshal Stability, Marshal Quotient, Indirect Tensile Strength (ITS), and Moisture Susceptibility parameters like the Indirect Tensile Strength Ratio (ITSR) and Retained Marshal Stability (RMS), were found to improve over time at each curing temperature. Using a high curing temperature further improved the mechanical characteristics of CBEM. The curing process was decelerated in case of CBEM prepared by high compactive efforts compared to CBEM prepared by low compactive efforts. The Michaelis-Menten model can be used to analyze moisture loss growth and the development of mechanical properties over time. The strength-maturity model can be developed by using ITS as strength parameters. There was a strong correlation between all mechanical characteristics and moisture loss.

Utilization of reclaimed asphalt pavement (RAP) materials in HMA mixtures for flexible pavement construction

Production of more RAP material waste arises the problem of deposition. To overcome this problem, RAP materials are recycled and re-used in different layers of pavement which will reduce the cost of pavement construction, reduce the environmental pollution. So, partial replacement with natural aggregate (NA) is an alternative for conservation of natural resources. RAP materials contain bitumen on their surface which will reduce the amount of natural bitumen. Replacement of RAP materials with natural aggregate needs suitable blending proportion. This paper represents laboratory evaluation of replacement of Reclaimed Asphalt Pavement (RAP) materials, a varying percentage of 0 to 30% blended with natural aggregate in terms of Marshall Stability, Indirect Tensile strength and Tensile Strength Ratio to be used in hot mix asphalt (HMA) mixtures for construction of surface course of flexible pavement. Marshall Stability, Indirect Tensile strength and tensile strength ratio (wet and dry condition) of natural aggregate blended with RAP 0%, 10%, 20% and 30% were tested and found 20% RAP mix is suitable for the bituminous road construction.

Early Strength of Cold Recycled Emulsified Asphalt Mixtures

In order to study the influence of different factors on the early strength of the cold recycled emulsified asphalt mixtures, 16 different types of cold recycled mixtures were designed and produced, which were combined with different cement content, water content, and cement-water ratio. The indirect tensile strength (IDT), compressive strength (UCS), tensile strength at 15°C (TS), and indirect tensile strength ratio (ITSR) tests were used to test the early strength of the cold recycled mixture. The variance analysis method was utilized to analyze the influence of the single factor on the early strength of the cold recycled mixture. The results show that appropriate cement-water ratio content can effectively improve the early strength of cold recycled mixtures. According to the Spearman correlation coefficient and comparison of each evaluation indicator, IDT and ITSR are significantly affected by various factors, and the results are relatively stable and well-differentiated, which is recommended as indicators of early strength evaluation. Cement-water ratio is recommended as the main control factor to control the early strength of the cold recycled emulsified asphalt mixtures. The optimal cement-water ratio ranges from 0.6 to 1.0, while the cement content is controlled from 1.2% to 1.5% and the water content from 3.8% to 4.3%. This study is of great significance for promoting the design of emulsified asphalt cold regenerative mixture with cement-water ratio and improving and accelerating its early strength development.

Waste Silt as Filler in Hot Mix Asphalt: A Laboratory Characterization

Several studies aimed to improve both the performance and environmental impact of asphalt pavements using waste and recycled materials as fillers. This study focused on the effect of untreated and thermally treated silt as a filler in hot mix asphalt (HMA). The silt used in the study was a byproduct from a local aggregate production plant in Bologna, Italy. Mineral and chemical analyses revealed that the waste silt required thermal treatment at 750 °C for 2 h. The study compared the use of calcined silt, untreated silt, and a common limestone filler in the production of asphalt mastics and HMA specimens. The rheological properties of the mastics were analyzed using frequency sweep and multiple stress creep recovery tests. The physical and mechanical characteristics of the HMAs were evaluated through the air voids content, Marshall stability and indirect tensile strength tests. Additionally, the water susceptibility and thermal sensitivity of the HMAs were evaluated through the indirect tensile strength ratio and indirect tensile stiffness modulus at different testing temperatures. The results showed that the addition of calcined silt had no significant effect on the rheological properties of the mastic or the optimal binder content. However, the samples produced with thermally treated silt showed the highest stiffness and resistance to rutting compared with the other samples. On the other hand, the addition of untreated silt slightly decreased the stiffness value of the samples. In conclusion, the use of waste silt as a filler has potential as a sustainable and eco-friendly solution for HMAs.

Study of adhesion between steel slag aggregates and bitumen taking into consideration internal factors influencing moisture damage

Electric arc furnace slag (EAFS) has been proposed as a replacement in hot-mix asphalt. This work compares the physical–chemical-mineralogical and morphological factors involved in the moisture damage of natural aggregates and EAFS. Digital image analysis, aggregate-bitumen affinity based on 3 methods, and evaluation of water sensitivity (by indirect tensile strength ratio ITSR) tests were made. Findings showed that the sample with natural aggregates has an ITSR of 92%, and the samples with EAFS-replacement (coarse fraction) and with total EAFS-replacement exhibit 98% and 100% respectively. Our results suggest that EAFS can improve resistance to moisture damage due to positive aspects of internal factors.

Recycled concrete aggregate incorporated cold bituminous emulsion mixture: Mechanical, environmental and economic evaluation

The present study aims at exploring the effect of partially replacing virgin aggregates with recycled concrete aggregate (RCA) in cold bituminous emulsion mixture (CBEM). In the study different CBEM samples were prepared by replacing 10–50% virgin aggregates with RCA. These samples were tested for mechanical properties and moisture susceptibility parameters such as Marshall Stability, Marshall Quotient (MQ), Indirect Tensile Strength (ITS), Retained Stability (RS) and Tensile Strength Ratio (TSR). In order to deal with CBEM's inherent issues like lower strength, higher air voids, higher moisture susceptibility, apart from conventional stone dust filler two additional fillers lime and cement were also used. Environmental and economic analysis of all the samples were also carried out by calculating the cost and CO2-eq of the mixtures. Test results showed that RCA incorporation in CBEM has positive impact on the properties like Marshall Stability, MQ and ITS while it has negative impact on the moisture susceptibility. Inclusion of lime and cement fillers solved the issues related with moisture susceptibility. Further based upon the economic and environmental analysis it was found that RCA incorporated CBEM has significant economic and environmental benefits. Cement and lime fillers increased cost and CO2-eq of the mixtures but it was still lower than conventional HMA.