Search

In this research, the performance of asphalt mixtures modified with polyethylene polymer (PE) by adding 2%, 4%, and 6% percentages was evaluated. Two kinds of PE are employed: Low-Density PE (LDPE) and High-Density PE (HDPE). The semi-wet mixing technique (SWM) was conducted to avoid stability issue for PE-modified binder during storage condition. Many experimental tests were conducted to evaluate the ability of these mixtures to withstand the effects of loads and moisture. The hardness index of these mixtures was also measured to determine their resistance to the effects of high temperatures without causing permanent deformations. The results showed that adding PE led to a remarkable enhancement in the performance of PE-modified mixtures. The improvement in stability reached 113.36% when using HDPE and it was 86.19% for LDPE. For moisture resistance, it improved by 10.42% and 9.91% when using HDPE and LDPE, respectively. The modified mixtures also showed higher hardness index compared to the standard mixture. According to the outcomes of this research, it can be concluded that the optimum percentage for using PE polymer as a modifier in bitumen is 6% and HDPE is more effective than LDPE. Overall, the SWM is easier and more economical compared to the wet mixing. [ABSTRACT FROM AUTHOR]

Moisture damage (MD) in bituminous mixtures occurs due to the loss of cohesion in the bitumen or adhesion between the binder and aggregates. The existence of moisture may influence the bonding between aggregates and bitumen, which may affect the moisture susceptibility of the bituminous mix. Therefore, there is a need to understand the bonding-debonding properties and the moisture susceptibility of binders and mixes, at the material selection stage. Surface free energy (SFE) method is one of the proven techniques to quantify the moisture susceptibility of bituminous mixtures, by using contact angle (CA) determination of the component materials of the mix. This study aimed to evaluate the effect of hydrated lime (HL) on the moisture susceptibility of bituminous mixtures, with control (VG30) bitumen and pyro-oil modified bitumen (POMB) having different percentages of pyro oil, using the SFE approach. Also, the study compared the SFE characteristics of VG30 and POMB with and without the optimum content of HL. POMB binders were prepared by the addition of high-density polyethylene (HDPE) pyro oil in percentages of 1, 3, and 5% in a control bitumen. HL was added as 20%, 25%, and 30% by weight of bitumen in VG30 and POMB bitumen. The aggregates used in the study were limestone, basalt, gravel, and their SFE components were directly considered from the literature. The sessile drop method was used to measure the CA of bitumen and, in turn, determine the various SFE parameters using Van Oss–Chaudhury–Good theory. The moisture susceptibility of mixtures with and without HL was evaluated and compared. From the results, the MD resistance of the bituminous mixtures with modified and unmodified bitumen was found to be increased after the optimum of HL, depending upon the type of aggregates used. Basalt has a 27.41%, 23.38%, and 10.48% greater energy ratio (ER) with POMB1/25, POMB3/25, and POMB5/30, respectively, than VG30/30, the highest ER in modified base bitumen. This indicates that HDPE pyro-oil treatment improves MD resistance for basalt. Whereas for limestone and gravel, VG30/30 gives a maximum value of ER as compared to any other combination of HL modified POMB. The ER values would assist highway agencies in selecting the most compatible binder–aggregate combinations. [ABSTRACT FROM AUTHOR]

Moisture damage has been identified as one of the most common causes of distress in asphalt mixes. The attachment between bitumen aggregate components deteriorates when water interacts at the interface, causing the binder to be stripped from the exterior of the aggregate and cohesive breakdown inside the asphalt binder. To reduce the moisture sensitivity of asphalt mixes, styrene-butadiene rubber (SBR) and antistripping warm mix additive (WMA) have been frequently utilized. Nevertheless, the application of SBR and WMA as a compound modifier has yet to be investigated thus this research aims to evaluate the influence of SBR and WMA i.e., ZycoTherm on the moisture resistance of asphalt mixtures. For this reason, several tests, including modified Lottman, resilient modulus, and dynamic creep, were used to assess the mechanical properties of the mixes in both wet and dry situations. The results found that the SBR improved the mechanical performance of the mixture in dry conditions, whereas using the ZycoTherm as a single modifier was more effective in improving the performance of the mix in dry conditions. However, the application of the compound modifier (SBR and ZycoTherm) could optimize the performance of asphalt mixtures in both conditions i.e., dry and wet. [ABSTRACT FROM AUTHOR]

Moisture-induced damage is a serious problem that severely impairs asphaltic pavement and affects road serviceability. This study examined numerous variables in asphalt concrete mixtures to assess their impact on moisture damage resistance. Mix design parameters such as the asphalt content (AC) and aggregate passing sieve No. 4 (PNo. 4) were considered as variables during this study. Additionally, hydrated lime (HL) was utilized as a partial substitute for limestone dust (LS) filler at 1.5% by weight of the aggregate in asphalt concrete mixtures for the surface layer. This study also investigated the potential enhancement of traditional asphalt binders and mixtures by adding nano-additives, specifically nano-silica oxide (NS) and nano-titanium dioxide (NT), at rates ranging from 0% to 6% by weight of the asphalt binder. To quantify the moisture damage resistance of the asphalt concrete mixes, two types of laboratory tests were employed: the tensile strength ratio (TSR) and the index of retained strength (IRS). The former characterizes moisture damage using tensile strength, whereas the latter uses compression strength. The physical properties of the asphalt binder, such as its penetration, softening point, and ductility, were also evaluated to identify the effects of the nanomaterials. The results indicated that variations in the mix design variables significantly affected the moisture damage resistance of the asphalt concrete mixtures. The maximum improvement values were obtained at the optimum asphalt content (OAC) and PNo. 4 (mid-range + 6%) with TSR values of 80.45 and 82.46 and IRS values of 74.39 and 77.14, respectively. Modifying asphalt concrete mixtures with 1.5% HL resulted in improved moisture resistance compared with mixtures without HL (0% HL) at each PNo. 4 level, reaching superior performance at PNo. 4 (mid-range + 6%) by 4.58% and 3.96% in the TSR and IRS tests, respectively. Additionally, both NS and NT enhanced the physical properties of the asphalt binder, leading to substantial enhancements in asphalt concrete mixture performance against moisture damage. A 6% dosage of NS and NT showed the best performance, with NS performing slightly better than NT. TSR was increased by 14.72 and 11.55 and IRS by 15.60 and 12.75, respectively, with 6% NS and NT compared with mixtures without nanomaterials (0% NM). [ABSTRACT FROM AUTHOR]

In this study, asphalt mixtures made by steel slag (SSA), copper slag (CSA), limestone (LA) and siliceous (SA) aggregates were subjected to different aging conditions; and were evaluated using Marshall, indirect tensile strength (ITS), Cantabro abrasion loss and semi-circular bending (SCB) tests. Results reveal that the moisture damage, raveling and fracture resistance of asphalt mixture decrease with aging and the ITS and Marshall properties improve with aging. After 7-day long-term aging, the TSR of the mixtures made by LA, SA, SSA and CSA, decreases, 28.8%, 48.5%, 8.8% and 15%, respectively, while, the ITS in dry condition increases, 61.9%, 33%, 62% and 81%, respectively. The fracture properties and moisture damage resistance of asphalt concrete made by SSA and CSA are less affected by aging than those made by LA and SA. Statistical analysis revealed that the effect of aggregate type, aging condition and their interaction on the mixture properties is significant. [ABSTRACT FROM AUTHOR]

Moisture damage has been identified as one of the most common causes of distress in asphalt mixes. The attachment between bitumen aggregate components deteriorates when water interacts at the interface, causing the binder to be stripped from the exterior of the aggregate and cohesive breakdown inside the asphalt binder. To reduce the moisture sensitivity of asphalt mixes, styrene-butadiene rubber (SBR) and antistripping warm mix additive (WMA) have been frequently utilized. Nevertheless, the application of SBR and WMA as a compound modifier has yet to be investigated thus this research aims to evaluate the influence of SBR and WMA i.e., ZycoTherm on the moisture resistance of asphalt mixtures. For this reason, several tests, including modified Lottman, resilient modulus, and dynamic creep, were used to assess the mechanical properties of the mixes in both wet and dry situations. The results found that the SBR improved the mechanical performance of the mixture in dry conditions, whereas using the ZycoTherm as a single modifier was more effective in improving the performance of the mix in dry conditions. However, the application of the compound modifier (SBR and ZycoTherm) could optimize the performance of asphalt mixtures in both conditions i.e., dry and wet.

Abstract Enhancing the performance of asphalt binders is essential for ensuring the long-term durability and serviceability of asphalt mixtures, as it can help reduce the frequency of maintenance and repair work, ultimately leading to the development of more sustainable transportation infrastructure. To achieve this goal, this study investigates the effects of incorporating recycled polymer materials, including reclaimed polyvinyl chloride (PVC) and polystyrene (PS) derived from household waste, into hot mix asphalt. The experimental work involved subjecting the polymer-modified asphalt binders to a range of physical tests, such as softening point, penetration, ductility, indirect tensile strength, Marshall stability, and moisture susceptibility, and the results showed that the addition of recycled polymers, with an optimal content of 4%, led to lower penetration values and higher softening point temperatures, indicating improved resistance to temperature changes. Further analysis of the asphalt mixture performance revealed several beneficial outcomes, including a decrease in flow, a boost in the asphalt mixture's resistance to moisture-induced damage, and an improvement in Marshall stability and indirect tensile strength, with the inclusion of 4% recycled polymers yielding increases in Marshall stability of 43.7% and 37.4% for PVC and PS-modified mixes, respectively, and increments in indirect tensile strength of 32.2% and 29.7% for the same mixes. The study concludes that the use of recycled polymers can effectively enhance the performance and durability of asphalt mixtures, contributing to the development of more sustainable asphalt pavement construction practices by utilizing locally available or reused materials, which could lead to the increased knowledge and application of stronger and more weather-resistant asphalt mixes, ultimately promoting the advancement of sustainable transportation infrastructure.

The dual nature of asphalt binder necessitates improvements to mitigate rutting and fatigue since it performs as an elastic material under the regime of rapid loading or cold temperatures and as a viscous fluid at elevated temperatures. The present investigation assesses the effectiveness of Nano Alumina (NA), Nano Silica (NS), and Nano Titanium Dioxide (NT) at weight percentages of 0, 2, 4, 6, and 8% in asphalt cement to enhance both asphalt binder and mixture performance. Binder evaluations include tests for consistency, thermal susceptibility, aging, and workability, while mixture assessments focus on Marshall properties, moisture susceptibility, resilient modulus, permanent deformation, and fatigue characteristics. NS notably improves binder viscosity by about 138% and reduces penetration by approximately 40.8% at 8% nanomaterial (NM) content, significantly boosting hardness and consistency. NS also enhances Marshall stability and decreases air voids, increasing the mix's durability. For moisture resistance, NS at 8% NM content elevates the Tensile Strength Ratio (TSR) to 91.0%, substantially surpassing the 80% standard. Similarly, NA and NT also show improved TSR values at 8% NM content, with 88.0% and 84.1%, respectively. Additionally, NS, NA, and NT reduce permanent deformation by 82%, 69%, and 64% at 10,000 cycles at 8% NM content, illustrating their effectiveness in mitigating pavement distress. Notably, while higher NM content generally results in better performance across most tests, the optimal NM content for fatigue resistance is 4% for NS and 6% for both NA and NT, reflecting their peak performance against various types of pavement distresses. These results highlight the significant advantages of nanoparticles in improving asphalt's mechanical properties, workability, stability, and durability. The study recommends further field validation to confirm these laboratory findings and ensure that enhancements translate into tangible improvements in real-world pavement performance and longevity. [ABSTRACT FROM AUTHOR]

Moisture damage of asphalt mixtures strongly depends on the physical and chemical properties of the bitumen. Aging affects these properties and, therefore, the moisture resistance of asphalt pavements. The strength of the bitumen and aggregates plays a key role in assessing the moisture damage of flexible pavements. Appropriate additives promote bitumen resistance and thus mitigate moisture damage. Here, the effect of aging, as well as nano-magnesium hydroxide (NMH) and dodecylamine (DA) additives on the moisture damage of samples containing granite and limestone aggregates with different hydrophilic properties and PG 64-16 and PG 58-22 bitumens was investigated by indirect tensile strength (ITS) and pull-off tests. The results of ITS tests showed that aging increased ITS in dry conditions and decreased it in wet conditions, while also reducing Tensile Strength Ratio (TSR) values. The magnitude of this reduction was greater in the samples containing granite compared to limestone aggregates. Both additives increased the TSR, but the TSR of DA-modified samples was higher than that of NMH-containing ones. The pull-off test was performed to determine the cohesion strength of the bitumen and the bitumen–aggregate adhesion strength. In this test, the cohesion strength was influenced by the bitumen, and the adhesion strength was affected by bitumen and aggregates. Both additives had positive effects on the bitumen's cohesion strength and the bitumen–aggregate adhesion. Among all the conditions, the greatest increase in adhesion and cohesion resistance was observed for the granite sample containing PG 58-22 bitumen modified with NMH. Moreover, bitumen aging significantly enhanced the cohesion strength and decreased the adhesion strength. [ABSTRACT FROM AUTHOR]

Stabilisation of road materials that do not meet specified requirements is a common practice in road construction. Cement and lime are among the most commonly used products for stabilisation. However, these products pose challenges in particular conditions, including rigidity and proneness to cracking, incompatibility with certain materials types and susceptibility to particular environmental conditions. In this regard, alternatives have been considered and nanotechnology-based materials have emerged as a viable option. For this study, the efficacy of Nano-Modified Emulsion (NME) for stabilisation of gravel material was investigated. The gravel material, stabilised with up to 1.5% NME was evaluated in the laboratory for mechanical strength characteristics and resistance to moisture damage. Results obtained for Static Triaxial Tests (STT) show that the NME improves the cohesion of the material by up to 54% but has no significant effect on the friction angle. Significant improvements are also noted in the results for California Bearing Ratio (CBR), Unconfined Compression Strength (UCS) and Indirect Tensile Strength (ITS) tests. The results also show that NME stabilisation improves the gravel material's resistance to moisture damage. Further investigations are recommended for repeated load triaxial tests, field trials, environmental risks and life cycle costs. [ABSTRACT FROM AUTHOR]

This study evaluated the individual and cumulative impact of different design factors on moisture damage of hot-mix asphalt (HMA) using the modified Lottman test. This study considered five different types of design aggregate gradations (DAG), three binder types, and three levels of compactive effort. To evaluate the significance of the influential factors that affected the moisture sensitivity of the mix, statistical analysis was performed. This study also investigated the influence of volumetric parameters of the bituminous mixes on moisture damage. The correlation of different design factors and various volumetric parameters with the tensile strength ratio (TSR) was further investigated through analysis using the Pearson correlation coefficient. The need for this investigation arises from the scarcity of comprehensive studies examining the individual and combined effects of various factors and the impact of volumetric parameters on moisture susceptibility. Additionally, linear regression models were developed to predict TSR based on the design factors and volumetric parameters considered in the study. The final model showed a close fit, with low mean absolute percentage error (MAPE=0.931) and a good coefficient of determination (R2=0.752). Moreover, based on the tested mixtures, the study establishes a threshold value of dry indirect tensile strength (ITSdry=750 kPa) and wet indirect tensile strength (ITSwet=650 kPa), along with TSR (= 0.85). [ABSTRACT FROM AUTHOR]

Moisture damage in asphalt mixtures is typically attributed to the loss of bond strength at the interface of the asphalt binder and aggregate matrix. Selecting an appropriate combination of materials that resist moisture-induced damage is therefore critical. This concern is of utmost importance when asphalt mixtures are prepared at lower temperatures (i.e. warm-mix asphalt (WMA) mixtures). An attempt was thus made to quantify the impact of moisture on asphalt mixtures prepared using four different WMA additives and two aggregates through bond strength tests. The results showed that WMA binders imparted similar or even higher bond strength than the base asphalt binder, regardless of the aggregate source and moisture exposure (wet or dry). The use of WMA additives improved the moisture sensitivity (evaluated through the bond strength ratio), despite lower production temperatures, compared with the base asphalt binder (VG30). Statistical analysis showed that the asphalt binder type significantly affected the bonding mechanism and moisture sensitivity. Based on the ranking protocol used in this study, use of the chemical-based WMA additive Rediset showed the best performance compared with other WMA additives in VG30. [ABSTRACT FROM AUTHOR]

The durability of an asphalt concrete pavement largely depends on the quality of the bitumen binder and the strength (or degree) of its interaction with the surface of aggregates (adhesion). The method is based on the finding of bitumen adhesion with a reference substrate, which is taken to be glass. The article presents the results of obtaining the adhesion to the glass surface: bitumen of different grades; bitumen modified with various additives; bitumen modified with adhesive additives and hardened by various methods. The results of comparing the adhesion of bitumen to the glass surface with the results of the Rolling Bottle Test are presented. It has been proved that, with a certain assumption, the value of adhesion to the glass surface can be taken as indicative value for the adhesion of unmodified bitumen to the surface of granite stone materials, obtained after 6 h of testing by the Rolling Bottle Test. [ABSTRACT FROM AUTHOR]

It is commonly known that mineral fillers significantly affect the asphalt mixture's performance. Superior flexible pavement performance can be ensured by gaining a deeper understanding of the function of filler. This research investigates the influence of three different fillers: granite dust, cement, and hydrated lime, at Australian asphalt mixtures. The testing program includes Marshall testing, moisture damage resistance, indirect tensile strength (ITS), and indirect tensile stiffness modulus (ITSM) tests of asphalt mixtures. Analysis of variance (ANOVA) was used to statistically assess the results obtained, besides damage analysis. The results indicate that using natural granite dust yields the highest resistance to moisture, while cement produces the highest stability, ITS, and ITSM. Unexpectedly, using hydrated lime filler decreases the stability/stiffness and moisture resistance of asphalt mixtures. ANOVA tests indicate that the type of filler affects ITS, TSR, and ITSM results (i.e., the p-value

The road construction industry aims to contribute to the protection of already compromised environment. Cold mix asphalt (CMA) is a measure initiated by the road industry to protect the environment and preserve energy. Despite having additional benefits, CMA has attracted little attention due to its inferior performance. CMA's performance is enhanced using a sustainable binder bio-modifier, natural cup lump rubber (CLR) is one of them. This study evaluated the tensile properties, rutting, moisture susceptibility, and adhesion properties of CLR-modified CMA (CMA-CR). The tensile property was enhanced by 26% due to CLR modification. CMA-CR had excellent rutting resistance of less than 2 mm rut depth at 10,000 load cycles, showing 70% improvement compared with conventional CMA. Moisture susceptibility evaluation indicated that CMA-CR had tensile strength ratio (TSR) value of 104%, satisfying the minimum 80% requirement of AASHTO T283. It also retained more than 96% bitumen coating. The moisture damage resistance was improved by 12% and 10% in terms of TSR and stripping, respectively. The durability results revealed that the CMA-CR mixture prevented higher mass loss, representing 14% improvement compared with conventional CMA.

Although bitumen makes up only a small portion of asphalt mixtures, it significantly impacts their performance. Over the past few decades, bitumen modifier additives, such as nano-silica, have been utilized to enhance asphalt performance. This research aims to investigate the influence of nano-silica on the mechanical properties of asphalt and bitumen mixtures. The study utilized crushed stone materials with grading No. 4 of the Iran Road Pavement code, 70-60 pure bitumen, and nano-silica in varying amounts (2%, 4%, and 6% by weight of bitumen). Marshall and resilient modulus tests were employed to evaluate the mechanical properties of asphalt mixtures, while Marshall's resistance ratio was used to assess moisture sensitivity. Additionally, tests on penetration degree, softening point, and elasticity were conducted to evaluate the effect of nanosilica on bitumen properties. The findings revealed that modification of bitumen with nanosilica led to decreased penetration, increased softening point, and reduced plasticity. Furthermore, the use of nano-silica improved Marshall strength and reduced Marshall's flow in asphalt mixtures, with a 6% addition of nano-silica increasing strength by 41% compared to the control sample. The addition of nano-silica also enhanced the moisture sensitivity of the mixtures and increased the resilient modulus by 95% compared to control asphalt samples. [ABSTRACT FROM AUTHOR]

Many waste materials can be repurposed effectively within asphalt concrete to enhance the performance and sustainability of pavement. One of these waste materials is sawdust ash (SDA). This study explores the beneficial use of SDA as a substitute for limestone dust (LD) mineral filler in asphalt concrete. The replacement rate was 0%, 15%, 30%, 45%, and 60% by weight of total mineral filler. Scanning electron microscopy (SEM) was employed to assess the surface morphology of Sawdust (SD), SDA, and LD. In addition, a series of tests, including Marshall stability and flow, indirect tensile strength, moisture susceptibility, and repeated uniaxial loading tests, were conducted to examine the performance characteristics of asphalt mixtures of different SDA content. As per Marshall mix design, a slightly higher binder content was required for the preparation of SDA mixes. The results reveal that the asphalt mixtures prepared using SDA attain a tensile strength ratio (TSR) greater than the critical threshold, i.e., 80%, indicating the feasibility of SDA against moisture-induced damage. The highest TSR value of 87% was obtained using 45% SDA as a replacement for LD. Compared to 0% SDA, there is a reduction of 12.08% in permanent deformation for asphalt mixtures produced with 60% SDA. Also, as the SDA content increases, there is a slight improvement in the resilient modulus values, with a peak improvement of 3% at 60% SDA. In addition, the cost of producing SDA mixes was relatively lower than the control mixes, indicating the cost-effectiveness of using SDA. Overall, the study found that SDA is a promising material that can improve the performance and durability of asphalt concrete at lower production costs. [ABSTRACT FROM AUTHOR]

The road construction industry aims to contribute to the protection of already compromised environment. Cold mix asphalt (CMA) is a measure initiated by the road industry to protect the environment and preserve energy. Despite having additional benefits, CMA has attracted little attention due to its inferior performance. CMA's performance is enhanced using a sustainable binder bio-modifier, natural cup lump rubber (CLR) is one of them. This study evaluated the tensile properties, rutting, moisture susceptibility, and adhesion properties of CLR-modified CMA (CMA-CR). The tensile property was enhanced by 26% due to CLR modification. CMA-CR had excellent rutting resistance of less than 2 mm rut depth at 10,000 load cycles, showing 70% improvement compared with conventional CMA. Moisture susceptibility evaluation indicated that CMA-CR had tensile strength ratio (TSR) value of 104%, satisfying the minimum 80% requirement of AASHTO T283. It also retained more than 96% bitumen coating. The moisture damage resistance was improved by 12% and 10% in terms of TSR and stripping, respectively. The durability results revealed that the CMA-CR mixture prevented higher mass loss, representing 14% improvement compared with conventional CMA. [ABSTRACT FROM AUTHOR]

Hot mix asphalt embedded on "Reclaimed asphalt pavement"(RAP) has the advantages of high technology. Moisture damage is a concern in these mixtures at all service temperatures. Therefore, the performance of this mixture against moisture at all service temperatures was considered a target of this research study. In this way, the effects of humidity on the performance of varieties were investigated using experimental methods including tensile strength ratio (TSR). In the framework of this study, Four different ratios of RAP for each of the surface and bonding layers (10%, 15%, 20%, 25%) and (30,40,50,60)% were added to the hot asphalt mix (HMA) for the two layers respectively to study and find the content Optimal RAP for both layers RAP through Marshall stability and hygroscopic resistance of asphalt mixtures through moisture damage is examined. The ratio (TSR) of the mixtures containing the optimal RAP content is compared with the asphalt mixture without RAP for three fillers and for both layers. The results showed a slight decrease in the tensile strength of the (HMA) that does not contain RAP compared to the asphalt control mixtures containing the reclaimed pavement, where it was found that the percentages were slightly higher and still higher than 80%. The results indicate that in general, Although there are old materials in the hot asphalt mix (HMA) produced from RAP, which include aggregates and bitumen binder surrounding the aggregate particles, the performance of these mixtures and integrations against moisture damage. Because it contains this, it can have results with “hot asphalt mixtures” containing RAP for areas with damage without worry in addition to good natural curbs.

Asphalt pavements in Malaysia suffer severe deterioration, such as raveling and stripping, because the bonding and adhesion between asphalt and aggregate is poor. Heavy rains throughout the year are the main cause of deterioration or a contributing cause to accelerated failure of the pavement structure. Therefore, it is very important to inspect the moisture damage and permeability behavior of asphalt pavement, which can effectively help in a pre-preservation program for asphalt pavement. This study aims to evaluate the effect of adding crumb rubber (CR) on the pavement permeability and moisture damage in highly unfriendly environmental conditions. Laboratory investigation was employed to achieve this aim. The laboratory investigation involved the preparation of two different ACW 14 rubberized asphalt mixtures (unaged and aged). Each type of rubberized mixture contained four CR contents (0%, 5%, 10%, and 15%). The mixtures were tested for air voids, Marshall stability and flow, moisture susceptibility, permeability, and water absorption. The laboratory investigation showed that the CR was appropriate for use up to 10% in asphalt mixtures. There were improvements in the performance of the asphalt mixtures including the Marshall stability, stiffness, durability and resistance against moisture damage. Furthermore, the use of CR prompted better permeability and water absorption. ACW 14 mixture is considered a practically impervious mixture. In conclusion, the application of rubberized pavement can enhance various phases of pavement life and structure by improving the structural performance and reducing environmental impact and landfill issues in the future. ABSTRAK: Turapan asfalt di Malaysia mengalami kemerosotan yang teruk seperti permukaan turapan jalan yang terpecah (rancak) dan berlubang (pelucutan) kerana ikatan dan lekatan antara asfalt dan agregat adalah lemah. Hujan lebat sepanjang tahun adalah punca utama kemerosotan atau penyumbang kepada struktur turapan rosak dengan cepat. Oleh itu, adalah sangat penting bagi memeriksa kerosakan disebabkan lembapan dan sifat kebolehtelapan turapan asfalt ini dapat membantu dengan berkesan dalam program pra-pemeliharaan turapan asfalt. Kajian makmal telah digunakan bagi mencapai tujuan ini. Kajian melibatkan penyediaan dua campuran asfalt bergetah ACW 14 yang berbeza (tidak berumur dan berumur). Setiap jenis campuran getah mengandungi empat kandungan CR (0%, 5%, 10%, dan 15%). Campuran telah diuji samada mempunyai lompang udara, kestabilan dan aliran Marshall, kerentanan lembapan, kebolehtelapan, dan penyerapan air. Kajian makmal menunjukkan CR sesuai digunakan sehingga 10% dalam campuran asfalt. Terdapat peningkatan dalam prestasi campuran asfalt termasuk kestabilan Marshall, kekakuan, ketahanan dan rintangan terhadap kerosakan lembapan. Tambahan pula, penggunaan CR mendorong kebolehtelapan dan penyerapan air. Campuran ACW 14 dianggap sebagai campuran praktikal tidak telap air. Kesimpulan, aplikasi turapan bergetah dapat meningkatkan pelbagai fasa hayat dan struktur turapan dengan menambah baik prestasi struktur dan mengurangkan kesan alam sekitar dan isu tapak pelupusan pada masa hadapan.

There are increasing interest in using nanoclay particles to improve asphalt binder and the produced concrete in pavement engineering. However so far most of the study was to directly use the nanoclays in natural material conditions, which come with some inefficient factors affecting the final effectiveness of the modified asphalt binder and the made concrete. This paper reports extensive experimental research on using preprocessed nanoclay, the Calcined Nano Montmorillonite (CNMM), to modify asphalt binder, compared with using natural Nano Montmorillonite (NMM). The nanoclays were added in asphalt as additive at different content rates ranging from 0% to 10% by the weight of asphalt binder. Experimental tests were performed on both of the modified asphalt binders and the concrete mixes using them. The study showed that at a 10% content CNMM demonstrated 32% improvement on Indirect Tensile Strength (ITS), and 5.25% less permanent deformation after exposed 10,000 load repetitions; at 6% CNMM presented 57.5% improvement on the CTindex for fatigue resistance. Meanwhile, the SEM analysis proved a distinctive morphological difference between NMM and CNMM, which indicates the optimized microscopic structure of the CNMM for the improvement on the interlock and adhesion with asphalt binder. In comparison, the optimum dosage for NMM is identified at 4%, while CNMM is at around 6%. The economic viability of the use of CNMM against the use of NMM has also been discussed in reference to the local material prices. In consideration of a balance between cost and performance, 6% content is recommended for the use of CNMM.

Reclaimed asphalt pavement (RAP) is a sustainable and cost-effective way to reduce the need for virgin asphalt in road construction and rehabilitation. However, RAP is often hard and brittle, leading to performance problems. Rejuvenators can be used to restore RAP's physical and rheological properties, but many conventional rejuvenators are petroleum-based and have environmental drawbacks. The objective of this study is to assess the rutting and moisture resistance characteristics of reclaimed asphalt mixtures rejuvenated with waste engine oil (WEO), with a particular focus on regions characterized by hot climates, such as Iraq. This study investigated WEO as a rejuvenator for RAP and oxidized asphalt grade 30–40. WEO is a waste product that can be recycled and reused, making it a sustainable and environmentally friendly rejuvenator. The study found that asphalt mixes containing RAP rejuvenated with WEO had improved mechanical performance compared to conventional asphalt mixes. Marshall stability increased by up to 30%, indirect tensile strength increased by up to 29%, moisture resistance improved by up to 19%, resilience to stripping increased by up to 97%, and rutting resistance increased by up to 64.5%. The study findings suggest that asphalt mixtures containing RAP rejuvenated with WEO are a promising new technology for sustainable road construction and rehabilitation. WEO is a waste product that can be recycled, reused, and used to produce asphalt mixes with improved mechanical performance. The novelty of this study is the use of WEO as a rejuvenator for RAP. WEO is a waste product that can be regenerated and reused, making it a sustainable and environmentally friendly rejuvenator. The study also investigated the optimal WEO concentration for rejuvenating RAP asphalt mixes, which is important for producing asphalt mixes with the desired performance characteristics.

Fatigue and moisture damage have been recognized as the most prevalent problems on asphalt roads, necessitating large annual expenditures for road maintenance. Much industrial waste is added to bitumen paving to enhance its conventional quality while decreasing the negative impacts on the natural environment and increasing resistance to pavement distress. This research uses ground granulated blast furnace slag (GGBFS) to substitute conventional filler (Portland cement [PC]) in hot mix asphalt (HMA). To determine how the GGBFS affects the HMA's susceptibility to moisture and fatigue cracks, Marshall characteristics, tensile strength ratio (TSR), and index of retained strength (IRS) of the asphalt concrete were evaluated. HMA was prepared with different rates of GGBFS (0, 25, 50, 75, and 100%) instead of PC. The data support the usage of 50% GGBFS in asphalt pavements as a partial replacement of PC, which enhanced Marshal stability by 34.4%, reduced flow value by about 12.9%, and increased TSR and IRS by 11.1 and 14.54%, respectively. The fatigue resistance of the modified asphalt mix at the optimum rate was evaluated with the four-point bending beam test; the fatigue life (Nf) increased by 33.8% relative to the reference mixture. The results obtained from this research hold scientific value for researchers and method designers aiming to enhance the resistance of hot asphalt mixtures to moisture and cracking. Using waste materials as an alternative to PC contributes to cost reduction while mitigating the environmental damages associated with cement manufacturing. To summarize, this research highlights the significance of exploring sustainable options in the construction industry, emphasizing the importance of reducing costs, and minimizing environmental impacts.

The increased demand for asphalt and other materials involved in the construction of pavement led to an increase in the cost of these materials, which calls for searching for alternatives to virgin materials that can be used to produce asphalt mixtures. Reclaimed asphalt pavement (RAP) was employed in this study and regenerated using oxidized asphalt modified with waste engine oil (WEO). This method can achieve economic and environmental benefits. After improving the properties of oxidized asphalt using WEO, it was used with reclaimed asphalt mixtures (RAP). When the RAP was added at ratios of 20, 30, 40, and 50%, an improvement can be noticed in the mechanical performance of the asphalt mixtures renewed with oxidized asphalt and WEO and an increase in its resistance to stripping. When reclaimed asphalt pavement (RAP) is added to hot mix asphalt (HMA) at concentrations of 20, 30, 40, and 50%, respectively, the Marshall stability of HMA is improved by 10, 20, 28, and 9.5%, the flow is declined by 1% for all ratios of RAP except for 50% RAP where the flow decline by 3%, the unit weight is enhanced, the quantity of air voids in the mix is preserved within allowable ranges, and the resistance to stripping is increased by 62, 77, 85, and 76%, respectively. Research also shows that incorporating 40% RAP enhances the resistance to moisture by about 5.9%. The addition of 40% RAP reduced the Cantabro loss values by about 2 and 16% for both aging and non-aging samples, respectively. The rutting resistance increased by 50 and 47% for mixes with 40% RAP at 50 and 60°C, respectively. As a result, it became evident that mixtures containing RAP material could be effectively adapted to satisfy the relevant volumetric and performance requirements.

Moisture-induced damage is a serious problem that severely impairs asphaltic pavement and affects road serviceability. This study examined numerous variables in asphalt concrete mixtures to assess their impact on moisture damage resistance. Mix design parameters such as the asphalt content (AC) and aggregate passing sieve No. 4 (PNo. 4) were considered as variables during this study. Additionally, hydrated lime (HL) was utilized as a partial substitute for limestone dust (LS) filler at 1.5% by weight of the aggregate in asphalt concrete mixtures for the surface layer. This study also investigated the potential enhancement of traditional asphalt binders and mixtures by adding nano-additives, specifically nano-silica oxide (NS) and nano-titanium dioxide (NT), at rates ranging from 0% to 6% by weight of the asphalt binder. To quantify the moisture damage resistance of the asphalt concrete mixes, two types of laboratory tests were employed: the tensile strength ratio (TSR) and the index of retained strength (IRS). The former characterizes moisture damage using tensile strength, whereas the latter uses compression strength. The physical properties of the asphalt binder, such as its penetration, softening point, and ductility, were also evaluated to identify the effects of the nanomaterials. The results indicated that variations in the mix design variables significantly affected the moisture damage resistance of the asphalt concrete mixtures. The maximum improvement values were obtained at the optimum asphalt content (OAC) and PNo. 4 (mid-range + 6%) with TSR values of 80.45 and 82.46 and IRS values of 74.39 and 77.14, respectively. Modifying asphalt concrete mixtures with 1.5% HL resulted in improved moisture resistance compared with mixtures without HL (0% HL) at each PNo. 4 level, reaching superior performance at PNo. 4 (mid-range + 6%) by 4.58% and 3.96% in the TSR and IRS tests, respectively. Additionally, both NS and NT enhanced the physical properties of the asphalt binder, leading to substantial enhancements in asphalt concrete mixture performance against moisture damage. A 6% dosage of NS and NT showed the best performance, with NS performing slightly better than NT. TSR was increased by 14.72 and 11.55 and IRS by 15.60 and 12.75, respectively, with 6% NS and NT compared with mixtures without nanomaterials (0% NM).

This research addresses the significant challenge posed by early water damage in highway asphalt pavement, a critical concern affecting pavement service performance. To counteract this issue, the utilization of anti-stripping agents in asphalt is explored as a highly effective technical intervention. In this investigation, a carefully selected amine-free additive was employed to modify the asphalt binder. A comprehensive array of physical and rheological tests, covering aspects such as storage stability, penetration, softening point, ductility, elastic recovery, rolling thin-film oven, retained penetration, the ductility of residue, and rotational viscometer assessments, were conducted to examine the multifaceted impact of the anti-stripping agent on the asphalt binder. Additionally, we assessed the asphalt mixture's sensitivity to moisture through Marshall stability tests after conditioning for 40 min and 24 h, followed by an enhanced immersion test and moisture susceptibility measurement. The results reveal a nuanced interplay of chemical and physical mechanisms influencing the behavior of the asphalt binder. Notably, the incorporation of an anti-stripping agent at a concentration of 0.25–0.5% (by weight of asphalt binder) led to a substantial improvement in the tensile strength ratio (TSR) to 94.9%, a noteworthy enhancement compared to the 80.6% observed with virgin asphalt mixture. Furthermore, the retained stability index (RSI) exhibited a remarkable increase to 98.1%, surpassing the 87.6% recorded for virgin asphalt. This study not only provides crucial insights into the intricate dynamics of asphalt binder performance but also emphasizes the pivotal role of anti-stripping agents in augmenting the structural integrity and resilience of asphalt pavement. [ABSTRACT FROM AUTHOR]

With the increase in asphalt mixtures sustainability, the application of waste as a bitumen modifier has been encouraged. In addition, the asphalt mixtures produced considering only the engineering properties show degradation due to repetitive traffic loading and not the performance properties. Thus, necessitate the use of an alternative mix design considering various properties and considering alternative modifiers. Also, there are limited studies on the impact of long-term water immersion on the strength of asphalt mixtures, particularly the effects of both immersion-drying (I-D) cycles on Palm oil clinker fine-modified bitumen (POCF-MB). Thus, this study employed palm oil clinker fine (POCF) as a bitumen modifier. Response surface methodology (RSM) was used to evaluate an alternative engineering and performance mix design technique for asphalt mixtures was examined. Subsequently, the durability and strength of the optimized POCF-MB asphalt mixture for both I-D cycles were evaluated. Samples were vacuum saturated and immersed for 0 (dry) 1, 3, 5, and 7 days. Then assessed in terms of Marshall quotient (MQ), retained Marshall stability (RMS), swelling index (SI), indirect tensile strength (IDT), Indirect tensile strength ratio (ITSR), and subsequently redried at ambient temperature to evaluate the retained durability and strength. The RSM findings show that the synergetic effects of POCF dosage and bitumen significantly impact performance. Based on the high coefficients of determination (R2) values (> 0.95), high adequate precision values (> 4), and low p-values for all responses, the statistical models were determined to be significant and well-fitted. The optimum values of numerical optimization were 5.86% POCF dosage and 4.65% bitumen content. The validation test shows an error margin of < 5% for all responses indicating that the model and experimental values agree well and are closely aligned. With increasing conditioning time, all samples showed increased SI, flow, and a decline in MQ, RMS, IDT, and ITSR. However, POCF-MB samples showed minimal moisture durability reduction, which can be attributed to the hydration process of the POCF, making the mixtures stiffer. After redrying POCF-MB samples show a higher recovery of their initial durability, revealing that the durability and strength properties of the asphalt mixture are recoverable. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering (17264073) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of this study was to evaluate and recommend an asphalt mixture design with emerging additive technologies that would provide superior performance against asphalt concrete (AC) stripping and cracking. To achieve this objective, a laboratory test program was developed to evaluate the use of nanomaterials (nanoclay and graphene nanoplatelet), an emerging anti-stripping agent (adhere), and warm-mix asphalt technologies (ZycoTherm, Sasobit, and EvoTherm). Two mix types were evaluated, which were a stone-matrix asphalt (SMA) and a dense-graded binder mix. In addition, the modified Lottman test (AASHTO T 283) and the indirect tensile asphalt cracking test (IDEAL-CT) test were used as performance indicators of moisture damage resistance and cracking susceptibility. Results were analyzed statistically to identify and quantify the effects of the design variables and selected additives on the performance, moisture damage resistance, and durability of asphalt mixes. Based on the cracking test results, a superior cracking resistance performance was observed with ZycoTherm, irrespective of the mix type. Adhere had the lowest average cracking indices for both mix types, which suggest that it would not perform as well as the other additives in terms of cracking resistance. Overall, SMA mixes displayed greater cracking resistance than the dense-graded mixtures, which may have been the result of the reclaimed asphalt pavement (RAP) material used in the dense-graded mix and its lower asphalt binder content. In terms of moisture resistance, both nanomaterials (graphene nanoplatelet and nanoclay) did not perform well as they did not meet the minimum required tensile strength ratio (TSR) criterion (>0.80). In addition, nanomaterials showed the lowest TSR values in both mix types suggesting that their effectiveness against moisture-induced damage may not be as good as warm-mix additives. On the other hand, warm-mix additives were expected to show enhanced performance in terms of moisture resistance as compared to the other additives evaluated in this study.

Incontinence-associated dermatitis, previously and sometimes still referred to as moisture lesions or moisture damage, is a commonly seen contact dermatitis that is a reactive response of the skin to chronic contact to urine and faecal matter. Understanding the etiology is fundamental to creating a skin care plan and successfully prevention. Systemic reviews and studies have shown that the continued variability in management results from a combination of knowledge base, observation, diagnosis, and product selection. This article aims to improve clinicians' understanding of incontinence-associated dermatitis and its management. [ABSTRACT FROM AUTHOR]

Indoor exposure to microbial growth, caused by moisture damage, has been an established health risk for several decades. It is likely that a damp indoor environment contains biological pollutants that trigger both the innate and adaptive branches of the immune system.In this study, we investigated the association between moisture damage related microbial exposure and serum C3a, C5a and CRP concentrations in Finnish adults.Serum C3a and CRP concentrations were elevated in individuals exposed to moisture damage and microbial growth in an indoor air environment. The elevated concentrations may be due to environmental factors present in moisture-damaged buildings. Complement activation and the resulting proinflammatory cleavage products may be a driving factor in inflammatory responses following exposure to indoor moisture damage and related microbial growth. Editor highlights: • Individuals with long term exposure indoor mold exhibit elevated concentrations of C-reactive protein. • Complement activation product C3a concentrations are higher on average in exposed individuals. • Findings corroborate previous observations, where indoor mold exposure was found to activate complement classical pathway.

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%.

Society must move towards an economy in which sustainability is its main driving force. A sustainable solution to avoid sending waste to landfill, the consumption of raw materials and, therefore, the depletion of natural resources, is the reuse or recycling of waste. Here, pavement engineering has great potential, as waste can be used for the manufacture of bituminous mixes. In particular, one of these residues is Marpol, which is generated during shipping, maintenance and cleaning operations, including wastewater and waste other than cargo waste. There are few studies on the analysis of its use in mixtures. Thus, in this work, the effect of partially replacing the binder of bituminous mixtures for another obtained from the treatment of Marpol oily waste was studied in order to contribute to environmental sustainability and circular economy. For this, water sensitivity, deformation and cracking resistance were analysed of two asphalt mixtures whose binder was partially replaced by Marpol binder. Furthermore, the binder ageing resistance was studied. The results obtained from the laboratory, plant and test section mixture were very close to those obtained for the reference. These results have demonstrated the feasibility of partially replacing the conventional binder by one obtained from Marpol waste. [ABSTRACT FROM AUTHOR]

The main objective of this study is to investigate the effect of moisture damage on the fatigue and cracking behaviors of warm mix asphalt (WMA) containing reclaimed asphalt pavement (RAP). To achieve this aim, different fatigue and cracking tests such as indirect tensile fatigue failure, four point beam fatigue, and semicircular bending tests have been conducted, and several parameters have been obtained. These parameters include tensile strength ratio (TSR) and fracture energy ratio (FER), indirect tensile fatigue ratio (IDTR), peak load ratio (PLR), J-integral ratio, and flexibility index (FI), and Nf and flexural stiffness ratios. The results showed that moisture-damaged RAP-WMA demonstrated slightly weaker fatigue and cracking resistance than other mixtures, which is not significant considering the environmental advantages of the mixture. Hence, RAP-WMA would be a proper and beneficial alternative as pavement material where there are significant problems in supplying natural aggregates, and issues like moisture damage and being environment friendly are big concerns. Also, it has been concluded that the fatigue test condition (stress and strain control modes) had a significant effect on the moisture damage investigation. [ABSTRACT FROM AUTHOR]

Reclaimed asphalt pavement (RAP) mixtures reduces environmental burden by utilising existing pavement material. However, RAP percent is limited due to performance issues at higher RAP content due to improper blending. The degree of blending can be improved using rejuvenator. Waste cooking oil (WCO) is gaining attention as a potential rejuvenator in recycled mixtures. However, past studies have shown contradictory results on WCO influence in asphalt mixture and have not investigated the influence of WCO on blending. This study is devised with a methodological approach to investigate the influence of WCO on blending in asphalt mixtures. Four blending approaches were formulated with four RAP and WCO contents resulting in a total of 148 mixture combinations. The blending characteristics were evaluated by assessing the workability and moisture damage resistance. The optimum mixtures were determined by Grey relational analysis, which were further investigated. The results showed the WCO doses determined from blending equation resulted in the higher dose than optimum WCO. The mixtures with medium dose and dry mixing of WCO showed the highest resistance to moisture damage. Further, for utilising higher than 30% RAP, higher binder content is required as compared to conventional mixture to increase the functional binder in the mixture. [ABSTRACT FROM AUTHOR]

The effects of short-term aging (STA) and long-term aging (LTA) on moisture damage mechanisms were investigated using mechanical and thermodynamic methods. PG58-22 and PG64-16 asphalt binders modified with Dodecylamine (DA) and Wetfix (WT) additives and limestone and granite aggregates were used. The moisture sensitivity was assessed using the indirect tensile strength (ITS) test via the modified Lottman test and the surface free energy (SFE) method. As asphalt binder becomes harder due to aging, ITS values increase in dry conditions. However, ITS values decrease due to the texture and mineralogical properties of aggregates, the reduction of mastic cohesion and asphalt binder-aggregate adhesion because of water infiltration and weakening of the mixture in wet conditions. The tensile strength ratio (TSR) test revealed that TSR values decrease due to aging. The cohesion free energy of the PG64-16 asphalt binder increased by 8.9% in the STA state and by 29.8% in the LTA state compared to the unaged state. This rise in PG58-22 was about the same as that in PG64-16. Asphalt binder aging in all the samples reduced the adhesion energy. These variations indicated that aging reduces the probability of cohesion failure and increases the probability of adhesion failure. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Nanchang University (Engineering & Technology) is the property of Nanchang University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Moisture damage and bond loss are major factors in pavement degradation, often stemming from excessive moisture accumulation due to weather events. Water infiltrates the gap between asphalt binder and aggregate, weakening the asphalt bond. Rigden Void (RV) has emerged as a crucial parameter in assessing the susceptibility of asphalt mastic-aggregate systems to moisture-induced damage. However, numerous waste natural fillers have been researched as potential aggregate filler replacements, yet their role in moisture damage remains unexplored. Therefore, this study aimed to understand how different fillers, including waste natural materials like coconut peat and bagasse, affect asphalt mixture performance and moisture damage. Results showed that Rigden Voids were positively correlated with pore size and negatively correlated with surface area. Larger pores contributed to higher Rigden Voids, while greater surface areas led to lower values. Limestone had the highest Rigden Void percentage due to its larger pore size and lower surface area. The research also explored contact parameters between fillers and asphalt, revealing varying interactions based on filler and asphalt types. Moisture damage testing demonstrated that all mixtures, both dense and porous, displayed good resistance to moisture damage. The correlation analysis between Rigden Voids and moisture damage revealed varying degrees of influence, dependent on asphalt type and aggregate gradation. [ABSTRACT FROM AUTHOR]

Aging is one of the factors affecting the physical and chemical properties of bitumen. This factor can lead to moisture damage in the asphalt mixture. The objective of this study is to investigate the effect of short-and long-term aging on the moisture damage mechanisms of hot mix asphalt containing Wetfix using the Pull-off method. Two types of bitumen with different performance grades (PG 58-22 and PG 64-16) modified with Wetfix BE additive and two types of aggregates (limestone and granite) were used. First, the rheological properties of bitumen and the physical characteristics of aggregates were determined, and then the chemical composition of aggregates were obtained through an X-ray fluorescence (XRF) test. After modifying the bitumens with Wetfix, the pull-off test was performed to determine the cohesion strength of bitumen and the adhesion strength of bitumen to aggregate on aged and unaged samples in dry and wet conditions. Short-term aging increased the cohesion strength and longterm aging caused a decrease in cohesion strength in wet conditions. Therefore, long-term aging leads to a decrease in bitumen performance in wet conditions and as a result, a decrease in pavement resistance against moisture damage. However, adding Wetfix increased the cohesion strength by 20%-32% and 26%-48% in short- and long-term aging, respectively, and adhesion strength by 43%- 26% and 57%-38% in short- and long-term aging, respectively. Comparing the effects of aging of base and modified bitumen on the reduction of adhesion and cohesion strengths shows that addition of Wetfix not only eliminates the negative effects of aging on these parameters, but also improves the resistance of modified bitumen, compared to base bitumen, against moisture damage. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate and recommend an asphalt mixture design with emerging additive technologies that would provide superior performance against asphalt concrete (AC) stripping and cracking. To achieve this objective, a laboratory test program was developed to evaluate the use of nanomaterials (nanoclay and graphene nanoplatelet), an emerging anti-stripping agent (adhere), and warm-mix asphalt technologies (ZycoTherm, Sasobit, and EvoTherm). Two mix types were evaluated, which were a stone-matrix asphalt (SMA) and a dense-graded binder mix. In addition, the modified Lottman test (AASHTO T 283) and the indirect tensile asphalt cracking test (IDEAL-CT) test were used as performance indicators of moisture damage resistance and cracking susceptibility. Results were analyzed statistically to identify and quantify the effects of the design variables and selected additives on the performance, moisture damage resistance, and durability of asphalt mixes. Based on the cracking test results, a superior cracking resistance performance was observed with ZycoTherm, irrespective of the mix type. Adhere had the lowest average cracking indices for both mix types, which suggest that it would not perform as well as the other additives in terms of cracking resistance. Overall, SMA mixes displayed greater cracking resistance than the dense-graded mixtures, which may have been the result of the reclaimed asphalt pavement (RAP) material used in the dense-graded mix and its lower asphalt binder content. In terms of moisture resistance, both nanomaterials (graphene nanoplatelet and nanoclay) did not perform well as they did not meet the minimum required tensile strength ratio (TSR) criterion (>0.80). In addition, nanomaterials showed the lowest TSR values in both mix types suggesting that their effectiveness against moisture-induced damage may not be as good as warm-mix additives. On the other hand, warm-mix additives were expected to show enhanced performance in terms of moisture resistance as compared to the other additives evaluated in this study. [ABSTRACT FROM AUTHOR]

Stone matrix asphalt (SMA) mixtures are the most resistant type of asphalt mixtures today in which the aggregate skeleton bears the bulk load. In this study, the effect of nano hydrated lime (NHL) on the moisture sensitivity of SMA mixtures was investigated. To examine the effect of NHL, the surface free energy (SFE) method and the dynamic modulus (DM) test were applied under wet and dry conditions on mixtures constructed with limestone and granite aggregates. The SFE results indicated that the granite aggregates had a greater polar component and limestone aggregates had a higher non-polar component which shows their higher moisture resistance. The adhesion free energy (AFE) results showed that the adhesion of base bitumen and limestone aggregate was higher, and using NHL improved the AFE values. The results of DM tests indicated that as the load cycles raised, the wet to dry DM ratio reduced and using NHL increased this ratio. The reduction slope of the DM ratio in samples constructed with granite aggregates showed a faster trend compared to limestone aggregates, and using NHL improved the resistance of SMA mixtures constructed with granite aggregates to moisture more than limestone aggregates. [ABSTRACT FROM AUTHOR]

Adhesion is easily affected by moisture erosion, thus reducing pavement performance. SBS modified asphalt is widely used in road engineering due to its excellent performance. For analyzing the adhesion properties between SBS modified asphalt and aggregates under moisture damage, the macro-scale SBS modified asphalt-coated aggregates and micro-scale asphalt-aggregate adhesion models were prepared first. The moisture damage was applied to the coated aggregates and adhesion models subsequently. After that, the quantitative boiling tests and molecular dynamics (MD) simulations were carried out. Finally, the multi-scale adhesion results were analyzed using Pearson correlation analysis. The macro-scale results imply that as the degree of moisture damage increases, the stripping area of the asphalt-aggregate interface rises. The micro-scale results reveal the moisture damage mechanism that is the penetrated moisture into asphalt-aggregate interface disrupt the adhesion force by the action of hydrogen bonds and Van der Waals forces. The Pearson correlation coefficient is 0.996, which indicates that the multi-scale adhesion results present an extremely strong linear relationship. This research contributes to the analysis of moisture damage in asphalt pavements in pluvial as well as seasonal frozen regions, and also provides a reference for correlation analysis between the multi-scale results. [ABSTRACT FROM AUTHOR]

Asphalt is widely employed in road construction due to its durability and ability to withstand heavy traffic. However, the disposal of waste polymers has emerged as a significant environmental concern. Recently, researchers have used polymer waste to modify asphalt pavements as a new approach. This approach aims to improve pavement performance and address the environmental concerns of polymer waste. Researchers have demonstrated that incorporating polymeric waste into asphalt mixtures can lead to performance improvements in asphalt pavements, particularly in mitigating common distresses including permanent deformation and thermal and fatigue cracking. The current comprehensive review aims to summarize the recent knowledge on the usage of waste polymers in asphalt mixtures, encompassing their impact on performance properties and mixture design. The review also addresses different types of waste polymers, their potential benefits, challenges, and future research directions. By analyzing various studies, this review offers insights into the feasibility, effectiveness, and limitations of incorporating waste polymers into asphalt mixtures. Ultimately, this contributes to the advancement of sustainable and environmentally friendly road construction practices. [ABSTRACT FROM AUTHOR]