Evaluation Of Crumb Rubber And Latex Modified Asphalt Binders For Pavement Crack Sealant Purpose

Conventional asphalt binder is widely used as the crack sealing material. Crack sealing is one of the most frequent pavement maintenance method. The level of performance during service life has a close relationship with the properties of asphalt binder used in the pavement or as crack sealant material. The rheological weakness of the conventional asphalt binder had sparked the interest of researchers to use polymer modified binder. The aim of this study is to develop crumb rubber and latex modified asphalt binders for crack sealant purpose. Different percentage of crumb rubber and latex were used which are 5 %, 10 %, 15 % for crumb rubber while 5 % and 10 % for latex. This is the most economical method that can be done in order to prolong the life span of pavement. Sealing the crack can prevent infiltration of water. Zycotherm with the content of 0.1 % by weight of binder was used to ensure strong coating bonds between aggregate and asphalt binders. The study was divided into two phases. The goal of first phase is to test and compare the rheological properties of modified binders and unmodified binder. The rheological properties that had been tested are softening point, penetration value, elastic recovery and torsional recovery. These properties were all tested because it influences the performance of the sealant material. In the second phase, bond test and layer-parallel direct shear (LPDS) test were conducted. Bond test was carried out in order to evaluate the tensile strength of sealant material. LPDS was conducted to measure the asphalt binder resistance to shear stress. The results of rheological properties showed that with the increment in crumb rubber and latex content in the asphalt binder, the softening point of the binder increased significantly. This proved that modified binders are less temperature susceptible. While the penetration value decreases with the addition of crumb rubber and latex. This is due to crumb rubber and latex that has the ability to stiffen the binder. Other than that, elastic recovery and torsional recovery showed a positive result with the addition of modifier. The percentage of recovery for both elastic and torsional are relatively good with the presence of crumb rubber and latex. According to bond test results, by incorporating crumb rubber and latex, it is able to increase the tensile strength of the binder. Long term ageing effect were not considered in this study. While the results from LPDS showed that crumb rubber and latex modified binders have a very good resistance to shear stress. This crumb rubber and latex modified asphalt binders would lead to produce the most environmental friendly sealant material by using recyclable material and plant-based material. It is not only environmental friendly, but the performance of modified binder is far more better than conventional binder

The Characterisation of Fracture Resistance of Asphalt Mixtures Containing Rubber Modifiers and a Wax-Based Additive

Asphalt mixture modifcation with rubberised material frequently results in improved characteristics and extended service life in actual application. Tis research characterised the synergistic consequences of rubber modifers (crumb rubber powder (CRP) and natural rubber latex (NRL)) and wax-based admixtures (Tough Fix Hyper (TFH)) on the performance of the asphalt mixture from the fracture energy and laboratory fracture resistance perspectives. Semicircular bending (SCB) and indirect tensile strength (ITS) tests were conducted to assess the fracture properties of the asphalt mixture samples. To prepare asphalt mixture samples, the wet method was utilised. Higher CRP levels resulted in greater strength and a longer time to attain peak force for both control and mixtures containing wax admixture, as determined by SCB. Te interaction between the higher CRP or NRL content and the TFH additive enhanced the fracture resistance, indicating that the components are highly compatible. Te 10L + TFH additive produced the highest fraction of energy, indicating a more signifcant improvement than the counterpart mixes containing the CRP modifer. In addition, incorporation of the CRP and NRL increased the fracture plastic zone (FPZ), resulting in increased fracture toughness. Terefore, the gradient of fracture toughness and fracture energy in the asphalt mix depends on the rubber type, content, and TFH. Although the higher CRP, NRL, and TFH improve the fracture energy and cracking resistance, they increase the crack initiation and propagation velocities, whereby the high bitumen stifness makes the mixture more brittle than the control mixture. Caution should be exercised when selecting the content of rubber modifer and TFH for the asphalt pavements in low-temperature service. Also, there is a direct interconnection between fracture resistance and fracture energy in the mixtures containing CRP, NRL, and TFH. Such correlations can be used as the premise of predictive micro- and macromodels to evaluate mixture performance in terms of fracture resistance

Moisture sensitivity and heavy metal leaching potentials of asphalt mixtures incorporating rubber modifiers and wax-based admixture

Moisture damage is one of the most frequent damages that occurs on asphalt pavements. The application of rubberized materials for asphalt is widely acceptable due to cost saving and environmentally friendly. The purpose of this study is to assess the performance of rubberized asphalt mixtures containing wax-based admixture, namely Tough Fix Hyper (TFH), in terms of moisture sensitivity and hazardous compound leaching potential. The moisture absorption, chemical immersion, and boiling water tests were used to assess the resistance to moisture damage on aggregate-binder bonding characteristics. Following that, the trend of moisture sensitivity was evaluated through an image analysis procedure. To simulate the environmental impact of leaching, the toxicity characterization leaching procedure (TCLP) test was adopted. The results showed that interaction between the crumb rubber or latex with TFH decreases the stripping value of the mixes significantly based on the chemical immersion test. Furthermore, the image analysis of the samples subjected to boiling water conditioning showed that pixels of asphalt samples without TFH, ranging from 524,949 to 472,346, decrease from 520,870 to 289,070, indicating that the asphalt remained coated area improved by 67.70–91.39%. The analysis of the leachate test revealed that the heavy metals, including arsenic (As), nickel (Ni), copper (Cu), chromium (Cr), vanadium (V), and cadmium (Cd), were not detected. However, zinc (Zn) was detected in the modified mixture, ranging from 0.05 to 0.114 mg/L, which lies within the allowable norm. In conclusion, the incorporation of crumb rubber and TFH in asphalt mixtures poses no environmental risk

Physicomechanical assessments and heavy metals’ leaching potential of modified asphalt binders incorporating crumb rubber and tin slag powders

Industrial solid waste has been widely used as an alternative additive for bituminous material modification. This study aims to evaluate the basic properties and quantify the leaching potential of modified asphalt binders incorporating crumb rubber powder (CRP) from waste tires and tin slag (TS) for a local smelting company. Three percentages of CRP and TS, at 5, 10, and 15%, were considered. The conventional asphalt binder (PEN 60/70), CRP, and TS-based modified asphalt binders were analyzed for toxicity, softening point, penetration value, elastic recovery, torsional recovery (TR), and coatability index. The findings indicated that the addition of the waste materials led to no significant heavy metal content in the asphalt binder mix. Moreover, the basic and physical properties of the asphalt binders were also improved by 5, 10, and 15% of the waste, respectively. However, TS waste exhibited limited effects on all the parameters and had a 5% optimum dosage. The modified binders’ results showed that the CRP modified asphalt binders had fewer heavy metals and responded more to elastic recovery and coatability

Impacts of recycled crumb rubber powder and natural rubber latex on the modified asphalt rheological behaviour, bonding, and resistance to shear

The objective of this study is to investigate the rheological properties, bonding and resistancetoshear of the rubberized modified binders under different conditions. A base asphalt binder with penetration grade 60/70 was utilised in this study. The crumb rubber and natural rubber latex were added at different percentages for the modified bitumen production, and computed based on the mass of bitumen. Silane additives at the rate of 0.1% by mass of asphalt binder were used as a surfactant. A series of rheological properties and recovery test were conducted on all binders. While bond test and Layer-Parallel Direct Shear (LPDS) test were carried out in order to simulate the crack movement of pavement. The results show that the addition of crumb rubber and latex positively impacts the performance of the asphalt binder. The crumb rubber and natural rubber latex modified asphalt binder has comparatively identical elastic recovery outcomes, while it also helps in enhancing the stiffness in terms of softening and penetration value. However, natural rubber latex modified asphalt binder performed much better than crumb rubber modified asphalt binder in terms of torsional recovery. Whereas, rotational viscosity test has been useful in adopting the suitable temperature which is 160 °C in order to satisfy the needs of better workability and to ensure it is pumpable. Storage stability test proved that the modified asphalt binders are homogenous since the temperature differences are less than 5 °C. The dynamic shear rheometer (DSR) test proved that the modified asphalt binder has better resistance to rutting. Through DSR findings and activation energy, the modified asphalt binder were catogorize as less susceptible to temperature changes. Finally, the crumb rubber modified asphalt binder did well in terms of bonding strength, while the natural rubber latex modified asphalt binder performed well in terms of resistance to shear. Overall, both rubberized modified binders performed better than the control sample

Assessments on the Performance of Asphalt Mixtures Prepared with Adhesion Promoters

Asphalt pavement is typically susceptible to moisture damage. However, it could be improved with the incorporation of additives or modifiers through binder modifications. The objective of the study is to assess the effect of adhesion promoters, namely PBL and M5000, onto the Hot Mix Asphalt (HMA). The performance of asphalt mixture has been assessed in terms of the service characteristics, the bonding properties, and mechanical performances. The service characteristics were assessed through the Workability Index (WI) and Compaction Energy Index (CEI) to evaluate the ease of asphalt mixture during the mixing and compaction stage. The bonding properties of the modified asphalt mixtures were determined using the boiling water test and static water immersion test to signify the degree of coating after undergoing specific conditioning period and temperature. The mechanical performances of the modified asphalt mixture were evaluated via Marshall stability, semi-circular bending, and modified Lottman tests. All specimens were prepared by incorporating adhesion promoters at the dosage rates of 0.5% and 1.0% by weight of asphalt binder. From the investigation, the bonding properties significantly improved for the modified asphalt mixture compared to the control mixture. The WI of the modified asphalt mixture increased while the CEI decreased in comparison to the control specimen. This implies the workability of modified asphalt mixture is better and requires less energy to be compacted. Modified asphalt mixture generally had better mechanical performance. Therefore, it can be deduced that the asphalt mixture with adhesion promoters have better overall performance than the control mixture

Improvements of TPS-porous asphalt using wax- based additives for the application on Malaysian expressway

Porous asphalt provides a sustainable approach to reduce traffic noise at source, while at the same time offering storm-water management systems which promote infiltration and often reduce the need for a detention pool. However, porous asphalt is prone to premature deteriorations, in terms of ravelling, and air voids clogging, rendering its unpopularity as the road surfacing material for expressways construction. In this research, the comparative influences of Tough Fix (TF) and Tough Fix Hyper (TFH) additives incorporation were evaluated on the performance of Tafpack-Super modified porous asphalt mixtures (TPS-PA). The Tafpack-Super (TPS) as a modifier at 20%, and anti-stripping additives (TF and TFH) with dosages used in this study were 0.3%, and 0.15% based on the weight of asphalt binder, respectively. Initially, the PA mixtures were prepared according to a predetermined mix design, and verified based on the percentage of air voids, permeability, and connected air voids. Comprehensive experimental tests of Marshall stability, permeability, Cantabro loss, rutting resistance, and moisture induced damage resistance were performed to assess the mechanical performance of the TPS-PA mixtures. Moreover, the Texas boiling test was employed to assess the stripping potential of loose TPS-PA mixtures. The experimental results revealed that both TF and TFH are capable of improving the PA resistance against rutting, ravelling, and moisture damage. In addition, the porous asphalt with TFH anti-stripping agent incorporation exhibited a superior overall performance as compared to the PA with TF

Effects of diluted methanol and water as foaming agents on the performance of latex foamed warm asphalt mixtures

Latex as an asphalt modifier has gained popularity in the asphalt industry as it improves the durability of asphalt pavement. However, the elastomeric properties of latex stiffen the asphalt binders, resulting in additional energy consumption during the production of asphalt mixtures, which may cause a higher emission of greenhouse gases. This is undesirable for sustainable development and the environment. In this study, the applicability of diluted methanol and water was comparatively evaluated as foaming agents in the production of warm mix asphalt (WMA) mixtures incorporating latex. Diluted methanol was used because it has a lower boiling point and latent heat than water, allowing the asphalt mixture to be produced at a lower temperature and thus consuming less energy. The performance of the foamed asphalt mixture was investigated through service characteristics, mechanical performance, and moisture susceptibility of mixtures. The service characteristics, on the other hand, were measured in a laboratory while preparing and compacting the asphalt mixture, which refers to the amount of energy required during the production and construction stages in the asphalt plant and on the construction site, respectively. The degree of energy required was assessed based on the workability index, coatability index, and the compaction energy index. The mechanical performance of asphalt mixtures was characterized by indirect tensile strength, resilient modulus, and dynamic creep tests. The resistance to moisture damage was evaluated based on the common parameter, indirect tensile strength ratio. The findings revealed that the use of diluted methanol foaming agent helped improve the workability of latex modified asphalt mixtures. The foamed latex-modified WMA demonstrated better performance compared to asphalt mixtures prepared using water as the foaming agent

Rheological and mechanical performance of asphalt binders and mixtures incorporating CaCO3 and LLDPE

This study was conducted to assess the performance of modified asphalt binders and engineering properties of mixtures prepared with incorporation 3 vol% and 6 vol% of calcium carbonate (CaCO3), linear low-density polyethylene (LLDPE), and combinations of CaCO3 and LLDPE. The rheological properties of control and modified asphalt binders were evaluated using a series of testing such as rotational viscometer (RV), multiple stress creep recovery (MSCR) and bending beam rheometer (BBR) tests. Meanwhile, four-point beam fatigue test, the dynamic modulus (E*) test and tensile strength ratio (TSR) test were conducted to assess the engineering properties of asphalt mixtures. Based on the findings, the RV and MSCR test result shows that all modified asphalt binders have improved performance in comparison to the neat asphalt binders in terms of higher viscosity and improved permanent deformation resistance. A higher amount of CaCO3 and LLDPE have led modified asphalt binders to better recovery percentage, except the asphalt binders modified using a combination of CaCO3 and LLDPE. However, the inclusion of LLDPE into asphalt binder has lowered the thermal cracking resistance. The incorporation of CaCO3 in asphalt mixtures was found beneficial, especially in improving the ability to resist fatigue cracking of asphalt mixture. In contrast, asphalt mixtures show better moisture sensitivity through the addition of LLDPE. The addition of LLDPE has significantly enhanced the indirect tensile strength values and tensile strength ratio of asphalt mixtures