International Journal of Pavement Research and Technology , 2024
Climate change and limited power supplies receive significant incentives to develop alternative p... more Climate change and limited power supplies receive significant incentives to develop alternative paving materials and technologies. Reclaimed asphalt pavement (RAP) and Warm Mix Asphalt (WMA) are technologies that can provide significant benefits to both the environment and the economy. This study used response surface methodology (RSM) to analyze the rutting resistance and moisture susceptibility of asphalt mixtures containing different amounts of RAP and doses and types of WMA. The experimental design was established utilizing the RSM with a central composite design (CCD) for varying RAP dosages (25-50%), WMA amounts (1.5-4%), and WMA types (waxy organic Asphaltan type A ® , and waxy organic Asphaltan type B ®). The moisture sensitivity and rutting resistance of asphalt samples were evaluated using the Modified Lottman method (AASHTO T 283) and wheel tracking test, respectively. RSM's statistical and mathematical models were employed to estimate the optimal value for RAP dose and WMA content and type. The results demonstrated that adding RAP to WMA mixtures increased the rutting and moisture resistance of asphalt samples. Also, the analysis of variance (ANOVA) results indicated that the increase in the WMA content led to a significant decrease in the rutting resistance, while the rise in the RAP content contributed to a significant enhancement in the rutting performance of the samples. The statistical outcome also showed that the moisture susceptibility of the mixture decreased significantly after increasing the RAP content, while the increase in WMA content did not have a significant influence on the moisture performance of the mix regardless of the WMA type. The research indicated that rutting resistance and moisture susceptibility have significant correlation coefficients (R2) of > 0.92, indicating that the model is highly correlated with the experimental results. Multiobjective numerical optimization led to the optimal design with 50% RAP and 1.5% WMA-type A. Validation findings indicate strong agreement and model effectiveness, with an error variance of less than 5% for all responses.
Evaluating the performance of rejuvenated asphalt mixes is crucial for pavement design and constr... more Evaluating the performance of rejuvenated asphalt mixes is crucial for pavement design and construction, as using a rejuvenator not only boosts recycling and contributes to positive effects on the environment but also increases the sensitivity to rutting and moisture. This study was executed to evaluate the effect of a warm mix asphalt (WMA) antistripping agent, namely nano-ZycoTherm, on the moisture-induced damage and rutting potential of asphalt mixtures containing 30% and 60% aged (RAP) binder and rejuvenated with 12% waste engine oil (WEO). For this purpose, the rutting resistance of asphalt mixes in wet and dry conditions was examined utilizing a loaded wheel tracker. In addition, the impacts of moisture on the performance of the mixtures were evaluated using different experiments, such as modified Lottman (AASHTO T283), resilient modulus, dynamic creep, aggregate coating and wheel tracking tests. Fourier transform infrared (FTIR) spectroscopy and thermogravimetric (TG) analysi...
IOP Conference Series: Materials Science and Engineering
Delays are a common problem in the global construction industry, affecting the development of the... more Delays are a common problem in the global construction industry, affecting the development of the road construction industry, particularly in developing countries. Where, the construction industry faces a lot of risk factors that can contribute to project delays, particularly during COVID-19. The road projects risk management framework was used to identify potential risk categories that could impede the success of road construction in Egypt. On the other hand, road construction in Egypt faces numerous challenges with increasing unexpected parameters throughout the project life cycle. In other words, unanticipated risk factors have a significant impact on the success of project execution. As a result, the study’s primary goals are to investigate the majority of the risk factors that cause road construction delays in Egypt. The impact of numerous risk factors has changed the delays in road projects as the COVID-19 pandemic spread across the world. As a result, the study incorporates p...
The increase in the amount of reclaimed asphalt pavement (RAP) and environmental concerns for bit... more The increase in the amount of reclaimed asphalt pavement (RAP) and environmental concerns for bitumen production have contributed to the use of RAP in road construction and maintenance. The use of higher than 15% of RAP adversely affects the physical and rheological properties of the asphalt binder and the mechanical properties of mixtures. Therefore, the use of bitumen and asphalt mixture improver were necessary to reduce the negative effects generated with the use of RAP. This paper aims to study the effect of fiberglass (FG) (0.5%, 1.0%, 1.5%, and 2%) on the mechanical properties of asphalt concrete containing 25%, 50% RAP and 9% waste engine oil. The performance of RAP asphalt mixtures incorporated with FG was evaluated using the Marshall stability test, moisture susceptibility test, and immersion wheel rutting test. The results indicated that the use of FG and RAP materials to rejuvenated asphalt mixtures resulted in an increase in the values of Marshall stability and rutting r...
This paper aims to evaluate the possibility of using nanosilica fume as an economic and a viable ... more This paper aims to evaluate the possibility of using nanosilica fume as an economic and a viable alternative to high-cost nanomaterials as a prelude to the large-scale use of nanomaterials in the pavement. Therefore, nanosilica fume (NSF), as an industrial waste material, was employed at low contents (2, 4, 6, and 8%) and high contents (20, 30, 40, and 50%) by asphalt weight as modifying additives to asphalt binder. The chemically prepared nanosilica (NS), as a high-cost nanomaterial, was employed at the contents of 2, 4, and 6% by asphalt weight for comparison purposes. Transmission electronic microscopy was used for scanning the nanostructure particles, and scanning electron microscopy was utilized to assess the homogeneity of modified binders. Changes in the chemical bonds of the modified asphalts were investigated using Fourier transform infrared spectroscopy. The modified binder's physical–rheological properties, temperature susceptibility, aging effect, and economic benefit were investigated. Prediction models were utilized to estimate the rutting parameter ( G */sin δ ) for the modified asphalts. The results revealed that significant improvements in physical–rheological properties, temperature susceptibility, and rutting resistance of the modified asphalt with high contents of NSF were attained. It was found that the NSF additive significantly decreased the short aging acceleration compared to NS. Predictive equations with high correlation have been inferred to correlate NSF content with both the rutting parameter and the rotational viscosity of the modified asphalt, thus enabling the designer to select the appropriate NSF content to achieve specified binder characteristics in the mix to serve pavement performance conditions.
The concept of sustainability is considered essential in the development of the asphalt mixtures ... more The concept of sustainability is considered essential in the development of the asphalt mixtures industry, due to its economic and environmental benefits. This study attempts to highlight the potential benefits of sustainability using Reclaimed Asphalt Pavement (RAP). It reviews previous studies conducted on RAP to obtain the most important characteristics in how to use the optimal content of RAP and its effect on some basic properties such as resilient modulus, susceptibility to moisture, permanent deformation, and fatigue. This study mainly focuses on the advantages of using RAP materials in hot mix asphalt (HMA). The results indicated that adding 30% of RAP to virgin asphalt mixtures gives the best performance in terms of the most studied characteristics.
International Journal of Pavement Research and Technology , 2024
Climate change and limited power supplies receive significant incentives to develop alternative p... more Climate change and limited power supplies receive significant incentives to develop alternative paving materials and technologies. Reclaimed asphalt pavement (RAP) and Warm Mix Asphalt (WMA) are technologies that can provide significant benefits to both the environment and the economy. This study used response surface methodology (RSM) to analyze the rutting resistance and moisture susceptibility of asphalt mixtures containing different amounts of RAP and doses and types of WMA. The experimental design was established utilizing the RSM with a central composite design (CCD) for varying RAP dosages (25-50%), WMA amounts (1.5-4%), and WMA types (waxy organic Asphaltan type A ® , and waxy organic Asphaltan type B ®). The moisture sensitivity and rutting resistance of asphalt samples were evaluated using the Modified Lottman method (AASHTO T 283) and wheel tracking test, respectively. RSM's statistical and mathematical models were employed to estimate the optimal value for RAP dose and WMA content and type. The results demonstrated that adding RAP to WMA mixtures increased the rutting and moisture resistance of asphalt samples. Also, the analysis of variance (ANOVA) results indicated that the increase in the WMA content led to a significant decrease in the rutting resistance, while the rise in the RAP content contributed to a significant enhancement in the rutting performance of the samples. The statistical outcome also showed that the moisture susceptibility of the mixture decreased significantly after increasing the RAP content, while the increase in WMA content did not have a significant influence on the moisture performance of the mix regardless of the WMA type. The research indicated that rutting resistance and moisture susceptibility have significant correlation coefficients (R2) of > 0.92, indicating that the model is highly correlated with the experimental results. Multiobjective numerical optimization led to the optimal design with 50% RAP and 1.5% WMA-type A. Validation findings indicate strong agreement and model effectiveness, with an error variance of less than 5% for all responses.
Evaluating the performance of rejuvenated asphalt mixes is crucial for pavement design and constr... more Evaluating the performance of rejuvenated asphalt mixes is crucial for pavement design and construction, as using a rejuvenator not only boosts recycling and contributes to positive effects on the environment but also increases the sensitivity to rutting and moisture. This study was executed to evaluate the effect of a warm mix asphalt (WMA) antistripping agent, namely nano-ZycoTherm, on the moisture-induced damage and rutting potential of asphalt mixtures containing 30% and 60% aged (RAP) binder and rejuvenated with 12% waste engine oil (WEO). For this purpose, the rutting resistance of asphalt mixes in wet and dry conditions was examined utilizing a loaded wheel tracker. In addition, the impacts of moisture on the performance of the mixtures were evaluated using different experiments, such as modified Lottman (AASHTO T283), resilient modulus, dynamic creep, aggregate coating and wheel tracking tests. Fourier transform infrared (FTIR) spectroscopy and thermogravimetric (TG) analysi...
IOP Conference Series: Materials Science and Engineering
Delays are a common problem in the global construction industry, affecting the development of the... more Delays are a common problem in the global construction industry, affecting the development of the road construction industry, particularly in developing countries. Where, the construction industry faces a lot of risk factors that can contribute to project delays, particularly during COVID-19. The road projects risk management framework was used to identify potential risk categories that could impede the success of road construction in Egypt. On the other hand, road construction in Egypt faces numerous challenges with increasing unexpected parameters throughout the project life cycle. In other words, unanticipated risk factors have a significant impact on the success of project execution. As a result, the study’s primary goals are to investigate the majority of the risk factors that cause road construction delays in Egypt. The impact of numerous risk factors has changed the delays in road projects as the COVID-19 pandemic spread across the world. As a result, the study incorporates p...
The increase in the amount of reclaimed asphalt pavement (RAP) and environmental concerns for bit... more The increase in the amount of reclaimed asphalt pavement (RAP) and environmental concerns for bitumen production have contributed to the use of RAP in road construction and maintenance. The use of higher than 15% of RAP adversely affects the physical and rheological properties of the asphalt binder and the mechanical properties of mixtures. Therefore, the use of bitumen and asphalt mixture improver were necessary to reduce the negative effects generated with the use of RAP. This paper aims to study the effect of fiberglass (FG) (0.5%, 1.0%, 1.5%, and 2%) on the mechanical properties of asphalt concrete containing 25%, 50% RAP and 9% waste engine oil. The performance of RAP asphalt mixtures incorporated with FG was evaluated using the Marshall stability test, moisture susceptibility test, and immersion wheel rutting test. The results indicated that the use of FG and RAP materials to rejuvenated asphalt mixtures resulted in an increase in the values of Marshall stability and rutting r...
This paper aims to evaluate the possibility of using nanosilica fume as an economic and a viable ... more This paper aims to evaluate the possibility of using nanosilica fume as an economic and a viable alternative to high-cost nanomaterials as a prelude to the large-scale use of nanomaterials in the pavement. Therefore, nanosilica fume (NSF), as an industrial waste material, was employed at low contents (2, 4, 6, and 8%) and high contents (20, 30, 40, and 50%) by asphalt weight as modifying additives to asphalt binder. The chemically prepared nanosilica (NS), as a high-cost nanomaterial, was employed at the contents of 2, 4, and 6% by asphalt weight for comparison purposes. Transmission electronic microscopy was used for scanning the nanostructure particles, and scanning electron microscopy was utilized to assess the homogeneity of modified binders. Changes in the chemical bonds of the modified asphalts were investigated using Fourier transform infrared spectroscopy. The modified binder's physical–rheological properties, temperature susceptibility, aging effect, and economic benefit were investigated. Prediction models were utilized to estimate the rutting parameter ( G */sin δ ) for the modified asphalts. The results revealed that significant improvements in physical–rheological properties, temperature susceptibility, and rutting resistance of the modified asphalt with high contents of NSF were attained. It was found that the NSF additive significantly decreased the short aging acceleration compared to NS. Predictive equations with high correlation have been inferred to correlate NSF content with both the rutting parameter and the rotational viscosity of the modified asphalt, thus enabling the designer to select the appropriate NSF content to achieve specified binder characteristics in the mix to serve pavement performance conditions.
The concept of sustainability is considered essential in the development of the asphalt mixtures ... more The concept of sustainability is considered essential in the development of the asphalt mixtures industry, due to its economic and environmental benefits. This study attempts to highlight the potential benefits of sustainability using Reclaimed Asphalt Pavement (RAP). It reviews previous studies conducted on RAP to obtain the most important characteristics in how to use the optimal content of RAP and its effect on some basic properties such as resilient modulus, susceptibility to moisture, permanent deformation, and fatigue. This study mainly focuses on the advantages of using RAP materials in hot mix asphalt (HMA). The results indicated that adding 30% of RAP to virgin asphalt mixtures gives the best performance in terms of the most studied characteristics.
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