Cold Mix Asphalt Research Articles

Assessing the Moisture and Aging Susceptibility of Cold Mix Asphalt Concrete

Laboratory experience in Iraq with cold asphalt concrete mixtures is very limited. The design and use of cold mixed asphalt concrete had no technical requirements. In this study, two asphalt concrete mixtures used for the base course were prepared in the laboratory using conventional cold-mixing techniques to test cold asphalt mixture (CAM) against aging and moisture susceptibility. Cold asphalt mixtures specimens have been prepared in the lab with cutback and emulsion binders, different fillers, and curing times. Based on the Marshal test result, the cutback proportion was selected with the filler, also based on the Marshal test emulsion. The first mixture was medium setting cationic emulsion (MSCE) as a binder, hydrated lime, and ordinary portland cement as a filler (7.95% MSCE + 2%HL + 3% OPC). The second mixture used was medium curing cutback (MC-250) as a binder and ordinary portland cement as a filler (5.18% MC 250 + 5% OPC). The indirect tensile strength (ITS) of the samples was measured at 25 ° C. It was found that the cold mix with the MSCE binder had a high ITS value relative to the cold mix with the cutback asphalt binder (MC-250). The dry mixture of MSCE ITS was approximately 3.77 times the dry mixture of MC-250. The MSCE wet mix was about 4.2 times the wet MC-250 mix. Tensile strength ratio result (TSR %) for the MSCE binder mix and the cutback MC-250 binder mix showed that the MSCE mix has a reasonable moisture resistance (77% ) compared to the MC-250 mix (69.2 %). The aging test and aging ratio result showed that asphalt binder oxidation has a significant effect on age-related pavement degradation as it changes the time-temperature relationship depending on the viscoelastic properties of the asphalt binder. The result clearly showed that the MSCE binder mix had a high resistance to aging (440 Kpa) compared to the cutback (MC-250) binder mix (110 Kpa). In contrast, the MSCE aging ratio (90 %) was higher than the MC-250 ratio (85 %).

Influence of epoxy soybean oil modified nano-silica on the compatibility of cold-mixed epoxy asphalt

A novel compatibilizer epoxy soybean oil (ESO)/nano-silica was synthesized, and used to improve the compatibility between the resin (epoxy and curing agent) and asphalt to prepare cold-mixed epoxy asphalt (CMEA). The ESO/nano-silica was characterized by FTIR, x-ray photoelectron spectroscopy, fluorescence microscopy and DSC. The results indicated that the ESO reacted with nano-silica and Si–O–C bonds formed, revealing that the nano-silica was successfully modified by ESO. Meanwhile, the incorporation of ESO/nano-silica into CMEA could significantly enhance the compatibility between resin and asphalt, and the tensile strength, elongation at break and tensile toughness of CMEA was obviously increased. The compatibility between resin and asphalt was simulated by molecular dynamic simulation. The simulation results showed a good correlation with the experimental results. The solubility parameter could be a feasible indicator to differentiate the compatibility variation. The Van Der Waals contributed the most proportion to the interaction energy.

A comparative assessment of the physical and microstructural properties of waste garnet generated from automated and manual blasting process

Cold mix asphalt (CMA) is an eco-friendly sustainable asphalt mixture, mostly for asphalt surface treatments (ASTs). However, material compatibility and poor adhesion leading to high voids, moisture damage susceptibility, and weak early strength remain challenging. Efforts to solve this limitation is beamed towards binder improvement and modification with modifiers, adhesion promoters, or polymers. Other forms of AST mixture improvement entail supplementary cementitious reinforcing or pozzolanic agents in the form of by-products. In this study, the physio-mechanical and microstructural desirability of spent garnet for use as fine aggregate in CMA was explored. Spent garnet is a by-product of abrasive blasting, often produced in large quantities and disposed of in landfills. Often, spent garnet waste gets contaminated with toxic elements either during usage or in landfills. This study aimed to investigate the properties of Automatically (AG) and Manually generated (MG) spent garnet grades. The physio-mechanical, morphologic, and chemical parameters of spent garnet were assessed to achieve this aim. The result compared with relevant specifications on cold mixtures plus Jabatan Kerja Raya (JKR) requirement. Moreover, crystallinity and composition were studied using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and X-ray Fluorescence (XRF). The presence of toxic heavy metals that often contaminate spent garnet deposits in landfills was evaluated too. Results suggested that both AG and MG’s high sand equivalent and least water absorption of 98 %, 89 %, and 0.14 %, 0.23 % accordingly, and can replace sand in CMA. However, MG spent garnet is not desirable for chemically sensitive materials. The AG garnet was found to be Pyrope while the MG spent garnet is largely Almandine garnet – the strongest form of garnet, including traces of other garnet forms.

Effect of emulsifying agent on rheological properties of bitumen emulsion modified with different techniques of adding SBR latex polymer

ABSTRACT Improving the characteristics of bitumen emulsion is among important methods for the enhancement of cold asphalt mixture properties. Thus the researchers usually focus on different additives, polymers and also manufacturing methods to improve the quality of bitumen emulsion. Accordingly, in this study, the characteristics of different bitumen emulsions modified by Styrene–Butadiene Rubber (SBR) latex using various manufacturing techniques including co-milling, soap pre-batching and post-blending were investigated. Actually, the design procedure to optimise manufacturing of Polymer Modified Bitumen Emulsion (PMBE) was determined for modified cold mix asphalt using two emulsifiers. The results of basic tests, Linear Amplitude Sweep test (LAS) at moderate temperatures, Multiple Stress Creep Recovery (MSCR) at high temperatures and some traditional tests showed that each type of emulsifier had different behaviours in each method of polymer modification. In fact, the process of selecting suitable emulsifier and manufacturing method of PMBE enhanced rutting resistance at high temperature (MSCR), fatigue resistance at moderate temperature (LAS) and other physical properties. The findings indicated that the results of MQ3 samples were better than CECA samples in the most important parameters. Totally, co-milling in CECA emulsifier and soap pre-batching in MQ3 emulsifier also resulted in the best performance in physical properties, fatigue performance and rutting resistance.

Effect of geosynthetic reinforcement insertion on mechanical properties of hot and cold asphalt mixtures

The main objective of this research is to analyze the effect of the insertion of a geogrid reinforcement in the mechanical behavior of the hot mix asphalt (HMA) and the cold mix asphalt (CMA). For this purpose, an experimental program was developed, in which HMA and CMA were designed by the Marshall mix design method and specimens with and without a geogrid were molded. The mechanical properties were investigated through tensile strength (Brazilian test), resilient modulus and Marshall Stability tests. The insertion of the geogrid into the HMA provide an increase in the responses of reinforced specimens for the three analyzed tests, which is not observed in the CMA. The adhesion between the asphalt mixture and the geogrid is observed only in the hot asphalt mixture. Therefore, its mobilization shows to be dependent on the temperature of the asphalt mixture, which alters the viscosity of the asphalt binder. It is assumed that the geogrid reinforcement is mobilized due to the adhesion between this geosynthetic element and the hot asphalt mixture. Additionally, the trapping of the asphalt mixture in the geogrid mesh openings provides the formation of a structural system with higher interlocking, lower susceptibility to deformations and as a consequence greater mechanical strength and stiffness, in comparison to unreinforced systems.

Improving fracture and moisture resistance of cold mix asphalt (CMA) using crumb rubber and cement

Due to environmental and economic advantages, cold mix asphalt (CMA) can be considered as a good alternative to conventional hot mix asphalt (HMA). Nevertheless, it has inferior performance compared to HMA, so that the application of CMA is not recommended in the surface layer of pavements subjected to high traffic volume and/or regions with very cold or hot climate. Considering the high potential of distress occurring in the CMAs, this research is aimed at investigating the effect of crumb rubber (CR) on fracture and moisture damage resistance of the CMAs. Different CR percentages were applied through two different modification methods and, then by means of Semi-Circular Bending (SCB) test, the fracture energy and flexibility index (FI) of modified CMAs were obtained and compared with the unmodified HMA and CMA. The moisture sensitivity of the modified CMAs was also evaluated using modified AASHTO T 283. Moreover, the effects of the addition of cement along with CR were investigated. The results show that simultaneous use of 14% CR and 2% cement in the CMA can considerably improve the fracture and moisture damage resistance so that it has comparable performance to the conventional HMAs.

Preparation and Performance Evaluation of Cold Mix Asphalt Mixture.

Cold mix asphalt mixture has a low strength and poor water stability, hence to solve this challenge, a cold mix asphaltic liquid was prepared in this study based on microscopic properties. LB-10 gradation was adopted and basalt fiber was selected as a reinforcing agent. The optimum asphaltaggregate ratio was determined by the Marshall test, and mix proportion was also designed. The laboratory tests were used to systematically evaluate road performance of the cold mix asphalt mixture. From the test results, it was shown that the initial strength, molding strength, immersion Marshall strength, residual stability, freeze-thaw splitting ratio, residual rate and dynamic stability of self-made cold mix asphalt mixture were 2.42 kN, 4.87 kN, 6.79 kN, 92.8%, 82.05%, 99.5% and 632 times/mm respectively. The initial strength, molding strength and residual stability of mixture became 90.9%, 88.7%, and 96.2%, respectively of their former values after one-month storage, showing good workability. By analyzing its research data and comparing with its existing products, the developed cold mix asphalt mixture can not only meet the requirements for road performances of the cold mix asphalt mixture in terms of strength, workability and high temperature stability, but greatly improves the water stability, storage stability and cohesive performance of the mixture.

Studi Karakteristik Campuran Tambalan Cepat Mantap (TCM)

Patching road pothole can be done using Permanent Cold Patching (PCP). This research main aim was to analyze the characteristic of the PCP. PCP Super Cold Mix Asphalt was used for the experiment. The mixtures were compacted Marshall hummer in lab using, and plate compactor on site. It was obtained that: compaction temperature variation significantly affected the characteristic of the mixture. Compaction at 100°C and 150°C, met stability, porosity and VMA specification, but not for the VFB. It required more compaction energy. The stability of cold compacted mixture at the age of 1 hour gave 844.74 kg (min. 500 kg). Towards this value, at the age of 48 hours; 96 hours; 192 hours; 384 hours, respectively gave increase of stability of 102%; 140%; 183%; 187% and then constant. Cold compaction on site gave less performance with porosity values in a range of 4.585-8.22% (spec. 4% -10%), therefore the VFB is less than minimum 65% of VMA; the stability obtained was 1422.72 kg (>min 500kg) or 58% stability of the samples compacted in lab at the same 16 days of age where stability had become maximum (constant). Cantabro test result of the cold mix gave 100% weight loss (the sample disintegrated), meanwhile the hot mix only lost 7.56% from 16% max loss.

Preparation and performance characterization of a novel high-performance epoxy resin modified reactive liquid asphalt

In order to improve the mechanical, adhesion and high-temperature performance of liquid asphalt, Epoxy resin (EP) was blended to the liquid asphalt as a modifier. A novel cold mix asphalt was prepared by implementation the high-performance Epoxy resin modified Reactive Liquid Asphalt (ERLA) technology, where reactive liquid served as its main component. The produced cold mix asphalt had presented excellent rheological and mechanical properties (dynamic viscosity, plasticity, Marshall Stability, etc.), meeting or exceeding the requirements of pavement materials. The optimized composition for ideal comprehensive performance was studied by orthogonal designed experiments on the rheological and mechanical properties of ERLA. Infrared Spectroscopy (IR), Simultaneous Thermogravimetry & Differential Scanning Calorimetry (TG-DSC) and Laser scanning confocal microscopy (LSCM)) were used to characterize the functional group changes during curing reaction, and subsequently to evaluate the thermal stability of the material at high temperature and the compatibility of ERLA. Experimental results indicated the optimum composition of ERLA (by weight percent) is 15% reactive liquid, 40% epoxy resin and 45% original asphalt with curing agent, achieving a grade at PG 82-22. This ERLA has superior rheological and mechanical properties and therefore can be implemented for cold mix asphalt, leading to a more flexible and environment-friendly pavement construction.

Characterization and correlation analysis of mechanical properties and electrical resistance of asphalt emulsion cold-mix asphalt

Asphalt emulsion cold-mix asphalt (CMA) is generally characterized as an evolutive material, with its mechanical strength increasing with curing time. This study aims to characterize the development of the mechanical properties of asphalt emulsion CMA mixtures during the curing process and correlate them with their evolutive electrical resistances. To achieve this objective, the moisture loss, Marshall stability, indirect tensile strength (ITS), indirect tensile stiffness modulus (ITSM) and electrical impedance of CMA mixtures containing various percentages of Portland cement were evaluated at different curing times up to 28 days. These evolutive properties were then analyzed and their relationships were explored. It was found the mechanical performance of CMA was considerably improved by cement, and there were liner relationships between the Marshall stability, ITS and ITSM irrespective of cement content. Furthermore, the mechanical performance was closely related with the electrical resistance of each CMA mixture containing different amounts of cement, suggesting that it is potentially feasible to predict the evolutive mechanical performance of CMA from electrical resistance which can be measured non-destructively.

Evaluation of Cold Mix Asphalt Concrete Properties

Cold mix asphalt concrete is considered as a sustainable and green pavement, the aggregates and the binder can be mixed, laid, and compacted without consumption of energy. In this investigation, an attempt has been made to prepare cold mix asphalt concrete for base course construction. Two types of liquid binder, named Cationic emulsion Medium Setting CMS and Medium Curing cutback MC-250 have been implemented in preparation of Marshall specimens. Four types of additives, named Portland cement, coal fly ash, limestone dust and hydrated lime have been tried. Mixtures were subjected to aeration, then compacted. However, Specimens were subjected to curing before testing. It was concluded that mixtures with (optimum cutback content + 5% cement and 4 hours aeration and 24 hours curing at 60°C) and (optimum emulsion content +2% hydrated lime +3% cement or fly ash and 4 hours aeration at 25°C and 24 hours curing at 60°C) satisfies the volumetric and Marshall properties requirements for base course. It was recommended that increasing the aeration and curing periods is beneficial for the cold mix asphalt concrete in satisfying the specification requirements for base course. Keywords:Cold Mix; Asphalt Concrete; Cement; Lime; Fly ash; Marshall; Aeration; Curing;

Induction of microbial carbonate precipitation as a sustainable strategy for post-improvement and remediation of cold mix asphalt

Cold Mix Asphalt (CMA) is highly susceptible to moisture damage, manifesting itself in stripping, raveling, rutting, and cracking faults. This study aimed to tackle this concern with bio-treatment. In doing so, this effort investigates the efficacy of microbial calcium carbonate precipitation in (i) the post-bio-strengthening (PBS) of mechanical properties and (ii) bio-remediation (BR) of moisture damage in cold-mix asphalt emulsion mixtures. To study the post-bio-strengthening potential, a set of cold-mix asphalt specimens was sprayed and injected with bacterial culture medium and nutrient solution to induce calcium carbonate precipitation for the purpose of post-strengthening. Then, the effect of curing times of 7, 14, 28, and 56 days on the fixation of precipitates in the mixtures was examined. To study the bio-remediation potential, another set of cold-mix asphalt specimens was subjected to a freeze-thaw cycle (modified Lottman test) intended to cause moisture damage and bacterial culture medium and nutrient solution were injected, afterward. For these specimens, the appropriate curing time of the fixation process for the bio-remediation was determined. All specimens were subjected to the destructive and non-destructive tests of mechanical properties, semi-circular bending (SCB), moisture susceptibility and also Cantabro test to assess indirect tensile strength (ITS), Tensile strength ratio, Indirect tensile fracture energy ratio, percent of toughness loss, crack propagation by SCB fracture energy, ultrasonic pulse velocity ratio, electrical resistivity, as well as the abrasion resistance. The Analysis of Variance (ANOVA) of the results was performed at 95% confidence level. A Field Emission Scanning Electron Microscope (FESEM) examination was also performed to study the microstructure and precipitates formed in the mixtures. The results showed that the post-bio-strengthened specimens had significantly better mechanical and resistance to moisture damage properties than those of control. The moisture-damaged specimens that underwent the bio-remediation also showed significant improvements in mechanical properties, and in some cases were similar to the undamaged control specimens. The results indicate that microbial calcium carbonate precipitation (MCP) can serve as an effective and sustainable method for both post-strengthening and remediation of cold mix asphalt mixtures.

Research on compatibility mechanism of biobased cold-mixed epoxy asphalt binder

Cold-mixed epoxy asphalt (CEA) has attracted increasing attention as a superior steel bridge pavement material for its convenient construction and low energy consumption. In this paper, the compatibility of CEA was improved with incorporating biobased epoxidized soybean oil (ESO), and the micromorphology, dynamic mechanical properties, and mechanical properties were evaluated. The results showed that ESO made asphalt particles disperse uniformly, and decreased the number of the glass transition temperature of the CEA. ESO also increased elongation at break of the CEA. The compatibility mechanism was analyzed according to Fourier transform infrared spectrum and molecular dynamics simulation. The results showed that ESO did not react chemically with asphalt and epoxy monomer. Due to incorporating ESO into CEA, the difference values of cohesion energy densities and solubility parameters between asphalt and epoxy monomer decreased, while the interaction energy of the whole system strengthened.

Effect of aggregate type on moisture susceptibility of modified cold recycled mix asphalt: evaluation by mechanical tests and Surface Free Energy method

There are deficiencies associated with cold mix asphalts, specifically, cold recycled mix asphalts in comparison with hot mix asphalt or hot recycled mix asphalt such as higher moisture susceptibility. Moisture damage of asphalt mixtures is inversely related to the bond quality between aggregates and binder. In this study, Portland cement (PC) and acryl polymer (AP) additives were employed to improve this bond. The effectiveness of used additives in improving the moisture susceptibility of cold recycled mix asphalt was examined using Surface Free Energy (SFE) method. Indirect Tensile Strength test and Dynamic Modulus test were performed to validate SFE method results. Moreover, scanning electron microscope (SEM) images were obtained for better understanding of mixture's microstructure. Also, effect of using granite, limestone and recycled asphalt pavement (RAP) aggregates was evaluated. The findings showed that cement and acryl polymer additives improved resistance of different studied mixtures, specifically, cold recycled mix asphalt against moisture damage by improving the adhesion between aggregate and asphalt. Considering effect of aggregates on moisture susceptibility, limestone-mixtures had the highest resistance while the RAP-mixtures performed the worst among the three. Finally, it was shown that results of SFE method were compatible with the mechanical tests in predicting moisture damage.

Strength Prediction of Cold Asphalt Emulsion Mixtures Using the Maturity Method

AbstractThe lack of universal design standards for cold mix asphalt (CMA) has led to the use of laboratory–field correlation techniques to predict its strength. Such techniques disregard the gradua...

Evaluating the rutting resistance for half warm bituminous emulsion mixtures comprising ordinary portland cement and polymer

Comparison of Cold Mix Asphalt (CMA) technology to traditional Hot Mix Asphalt (HMA) technology, reveals that the first has several advantages in terms of economic, eco-friendly, safety and sustainability. A promising development of CMA technology is Cold Bituminous Emulsion Mixtures (CBEMs). Unfortunately, some characteristics of this technology are still in development need; namely high porosity, long curing time and low early strength. Half Warm Bitumen Emulsion Mixture (HWBEM) was introduced in previous attempt, as a treated CBEMs with optimum heating temperature being less than 100 °C. This work focuses on treating the CBEMs with low heat energy technique (i.e., microwave heating), plus two types of admixtures; Ordinary Portland Cement (OPC) and acrylic (AR) polymer. The effect of low energy heating (i.e., microwave heating) on developed CBEMs characteristics is tested. Acrylic (AR) polymer was utilized in percentages of 1.25, 2.5, 3.75 and 5% of the residual bitumen. The developed mixtures of HWBEM is tested statically by Marshall and dynamically by Wheel track parameters. The results reveal that the HWBEM with OPC and 1.25% AR, showed better deformation resistance roundly 81 times with vital development in its mechanical and volumetric properties comparable to traditional HMA. Therefore, low energy heating and polymer treatment sustain the new promising paving technology called HWBEM.

Improving the compatibility of cold-mixed epoxy asphalt based on the epoxidized soybean oil

Cold-mixed epoxy asphalt (CEA) has been used for paving steel bridges and high-grade roads because of its properties superiority and environmental protection. In order to obtain CEA with excellent performance, it is a significant mean to improve the compatibility between asphalt and epoxy resin (ER) by introducing epoxidized soybean oil (ESO). The viscosity and glass transition temperature (Tg) decrease, and the asphalt dispersed more uniformly in the ER with increasing ESO concentration. Based on the dynamic mechanical analysis, the CEA-ESO30 shows only one Tg and excellent compatibility between asphalt and ER. The elongation at break and storage modulus of CEA-ESO was higher than CEA, indicating that the flexible ESO molecular chain in the curing networks might improve the stiffness of CEA-ESO. The FTIR spectra exhibited that the ESO reacted with the curing agent to form 3D networks with ER, which may result in good compatibility between asphalt and ER.

The Evaluation of Short‐ and Long‐Term Performance of Cold‐Mix Asphalt Patching Materials

Potholes, one of the major types of distress on pavement surfaces, damage vehicles and are a safety hazard for the travelling public. In order to mitigate the effect of potholes, cold‐mix asphalt (CMA) patching materials are commonly used for urgent repair of pavement surfaces before resurfacing can be undertaken. Therefore, the short‐term (initial stability) and long‐term (in‐service durability) performance evaluation of CMA patching materials is necessary. This study conducted several curing conditions in the laboratory to investigate short‐term, long‐term, and moisture effects on pavement surfaces. Moreover, this study compared the Marshall stability of samples prepared under various compaction conditions. Marshall stability, Cantabro abrasion, and UK wheel tracking tests were conducted to evaluate the performance of CMA patching materials. The results indicated that the Marshall stability of dense‐gradation (DG) CMA patching materials was higher than that of open‐graded (OG) CMA patching materials and the Marshall stability of OG CMA patching materials was highly influenced by the coarse aggregate proportion. The DG and OG CMA patching materials exhibited comparable abrasion resistance, and the Cantabro abrasion ratio was highly correlated to the estimated asphalt film thickness for the OG CMA patching materials. A moisture indicator (MI) was proposed, and the effect of moisture damage on Marshall stability and Cantabro abrasion ratio was related to the proposed MI. The rutting resistance of the DG CMA patching materials was higher than that of the OG CMA patching materials, which is consistent with the Marshall stability result.

Effect of buton’s granular asphalt gradation on marshall stability of cold emulsified asphalt mixtures under wet condition

This study aims to compare the performance of Cold Mix Asphalt with Buton’s Granular Asphalt taking into account gradation of BGA and gradation of BGA Mineral in a combined gradation under wet condition. The specimens were made with optimum bitumen content of 8%, water content of 5%, and Buton’s Granular Asphalt content of 6-13.5%. Marshall Stability testing refers to National Standard of Indonesia number 06-2489-1991. The maximal Marshall Stability of CEAM under wet condition which takes into account gradation of BGA in combined gradation is obtained at BGA content of 11.75%. The maximal Marshall Stability of CEAM under wet condition which takes into account gradation of BGAM in combined gradation is obtained at BGA content of 11%. The Marshall stability of CEAM taking into account BGA gradation in combined gradation were higher of 3-14% than which takes into account the gradation of BGA Mineral. Therefore, design gradation of Cold Mix Asphalt using Buton’s Granular Asphalt which be recommended in The Construction and Building Guideline, Public Work Department of Republic of Indonesia of 2006, should be revised to take into account gradation of BGA in combined gradation.

Analysis of stability of residue asphalt emulsion mixture containing Buton Granular Asphalt (BGA)

The natural rock asphalt which available in abundance in the southeast of Buton Island, Indonesia was attempted to use in the production of cold mix asphalt. The purpose of this study is to replace petroleum bitumen with local materials such as natural rock asphalt. Small granular size of natural rock asphalt that referred to Buton granular asphalt (BGA) was blended with petroleum bitumen as droplet phase in the asphalt emulsion mixture. Mixture with 8.8% of asphalt emulsion mixture made with the cationic slow setting (CSS) that corresponded to the residue asphalt emulsion content was used as a mixture control. At residue asphalt emulsion content, bitumen of BGA was used for petroleum bitumen partial replacement in the asphalt emulsion mixture production. Test result revealed that utilizing BGA in asphalt emulsion mixture has proved for improving stability where the stability of all mixture with BGA super passed the stability of mixture without BGA.