Pub Date : 2021-10-17DOI: 10.22075/JRCE.2021.23385.1510
H. Jahangir, M. Khatibinia, Mehran Mokhtari Masinaei
Detection of damages in structures during their service life is of vital importance and under attention of researchers. In this paper, it is attempted to identify damages in prestressed concrete slabs using vibration responses obtained from modal testing in the time domain. For this purpose, first some damage scenarios with various geometric shapes and at different locations of numerical models, corresponding to a prestressed concrete slab, were created. Next, the impact hammer force in the modal test was simulated and the accelerations time histories at different degrees of freedom corresponding to the numerical models per two states of damaged and undamaged structure were selected as the inputs for a number of damage indices to identify the damage locations. Some of these damage scenarios have been located at the middle of prestressed concrete slabs and some at the corners. The proposed damage indices in this research are obtained based on the area under the diagram of acceleration time histories, maximum and also the area under diagram of detail coefficients of the wavelet transform using the three wavelet families of Daubechies, Biorthogonal and Reverse Biorthogonal. The results showed that using damage index obtained from the area under diagram of detail coefficients of wavelet transform with the mother wavelet db2 could detect the damage scenarios at the middle and corners of the slab with a well precision. Furthermore, the damage scenarios at the corners of numerical models could be detected properly by using the mother wavelet rbio2.2 in the proposed damage index.
{"title":"Damage Detection in Prestressed Concrete Slabs Using Wavelet Analysis of Vibration Responses in the Time Domain","authors":"H. Jahangir, M. Khatibinia, Mehran Mokhtari Masinaei","doi":"10.22075/JRCE.2021.23385.1510","DOIUrl":"https://doi.org/10.22075/JRCE.2021.23385.1510","url":null,"abstract":"Detection of damages in structures during their service life is of vital importance and under attention of researchers. In this paper, it is attempted to identify damages in prestressed concrete slabs using vibration responses obtained from modal testing in the time domain. For this purpose, first some damage scenarios with various geometric shapes and at different locations of numerical models, corresponding to a prestressed concrete slab, were created. Next, the impact hammer force in the modal test was simulated and the accelerations time histories at different degrees of freedom corresponding to the numerical models per two states of damaged and undamaged structure were selected as the inputs for a number of damage indices to identify the damage locations. Some of these damage scenarios have been located at the middle of prestressed concrete slabs and some at the corners. The proposed damage indices in this research are obtained based on the area under the diagram of acceleration time histories, maximum and also the area under diagram of detail coefficients of the wavelet transform using the three wavelet families of Daubechies, Biorthogonal and Reverse Biorthogonal. The results showed that using damage index obtained from the area under diagram of detail coefficients of wavelet transform with the mother wavelet db2 could detect the damage scenarios at the middle and corners of the slab with a well precision. Furthermore, the damage scenarios at the corners of numerical models could be detected properly by using the mother wavelet rbio2.2 in the proposed damage index.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"69 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90789101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-17DOI: 10.22075/JRCE.2021.22564.1487
E. Rajabi, G. G. Amiri
Cumulated damages caused by the past earthquakes lead to structural damage. Ensuring the safety of individuals – especially in highly populated buildings – and the continuity of immediate occupancy in consecutive earthquakes with short periods is an important matter to consider in seismic design codes. The use of strategies, such as identifying damage sensitive stories, can help ensure the safety of such buildings. This paper identifies damage sensitive stories for reinforced concrete (RC) and steel frames based on damage distribution caused by critical mainshock-aftershocks. In this regard, short, medium and relatively tall steel and RC frames with 3 and 5, 7, 10, 12 and 15 stories are analyzed under single and successive scenarios in the OpenSees software. Damage distribution of frames show that the upper stories in frames with low and medium height and middle stories toward higher stories in relatively tall frames are damage sensitive stories. Also, when tested against successive shocks, the initially-damaged steel frames experienced more destruction than RC frames. In severe conditions, the increased damages of steel frames were about 57%, 94%, 42%, 33% and 84% more than those of the RC frames. Moreover, steel frames with 15 stories were better able to sustain additional damages than RC frames (by about 1.84 times).
{"title":"Damage Sensitive-Stories of RC and Steel Frames under Critical Mainshock-Aftershock Ground Motions","authors":"E. Rajabi, G. G. Amiri","doi":"10.22075/JRCE.2021.22564.1487","DOIUrl":"https://doi.org/10.22075/JRCE.2021.22564.1487","url":null,"abstract":"Cumulated damages caused by the past earthquakes lead to structural damage. Ensuring the safety of individuals – especially in highly populated buildings – and the continuity of immediate occupancy in consecutive earthquakes with short periods is an important matter to consider in seismic design codes. The use of strategies, such as identifying damage sensitive stories, can help ensure the safety of such buildings. This paper identifies damage sensitive stories for reinforced concrete (RC) and steel frames based on damage distribution caused by critical mainshock-aftershocks. In this regard, short, medium and relatively tall steel and RC frames with 3 and 5, 7, 10, 12 and 15 stories are analyzed under single and successive scenarios in the OpenSees software. Damage distribution of frames show that the upper stories in frames with low and medium height and middle stories toward higher stories in relatively tall frames are damage sensitive stories. Also, when tested against successive shocks, the initially-damaged steel frames experienced more destruction than RC frames. In severe conditions, the increased damages of steel frames were about 57%, 94%, 42%, 33% and 84% more than those of the RC frames. Moreover, steel frames with 15 stories were better able to sustain additional damages than RC frames (by about 1.84 times).","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"104 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79187783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-17DOI: 10.22075/JRCE.2021.22745.1491
Seyed Reza Siadati, V. Broujerdian, E. M. Dehcheshmeh
In this study, the progressive collapse of reinforced concrete structures due to vehicle collision to the columns of the ground floor was modeled and examined. For this purpose, a four-story reinforced concrete building with the intermediate moment frame system was designed using ETABS software followed by the simulation of impact loading by SAP2000 software. Performing non-linear time history dynamic analysis, the critical forces required to the column failure were determined via trial and error by considering different live load contribution. Then, the corresponding critical velocities for 4, 8, and 12 ton vehicles were determined. Finally, the progressive collapse of the building was examined by the sudden removal of the column. The results showed that by increasing the percentage of live load contribution, the force and critical velocity for the instability and damage of the column will decrease. Furthermore, comparing the perimeter and corner columns showed that the corner columns are the most critical columns for occurrence of the progressive collapse. In addition, during the assessment of the progressive collapse, it was found that the number of damaged springs in the corner column removal scenario is less than that of the perimeter column removal scenario.
{"title":"Evaluation of Intermediate Reinforced Concrete Moment Frame subjected to Truck collision","authors":"Seyed Reza Siadati, V. Broujerdian, E. M. Dehcheshmeh","doi":"10.22075/JRCE.2021.22745.1491","DOIUrl":"https://doi.org/10.22075/JRCE.2021.22745.1491","url":null,"abstract":"In this study, the progressive collapse of reinforced concrete structures due to vehicle collision to the columns of the ground floor was modeled and examined. For this purpose, a four-story reinforced concrete building with the intermediate moment frame system was designed using ETABS software followed by the simulation of impact loading by SAP2000 software. Performing non-linear time history dynamic analysis, the critical forces required to the column failure were determined via trial and error by considering different live load contribution. Then, the corresponding critical velocities for 4, 8, and 12 ton vehicles were determined. Finally, the progressive collapse of the building was examined by the sudden removal of the column. The results showed that by increasing the percentage of live load contribution, the force and critical velocity for the instability and damage of the column will decrease. Furthermore, comparing the perimeter and corner columns showed that the corner columns are the most critical columns for occurrence of the progressive collapse. In addition, during the assessment of the progressive collapse, it was found that the number of damaged springs in the corner column removal scenario is less than that of the perimeter column removal scenario.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88958204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-15DOI: 10.22075/JRCE.2021.23237.1504
A. Farahani
In this study, the replacement of corroded reinforcement with new reinforcement as a rehabilitation method is considered to reduce the impact of corrosion on the performance of reinforced concrete structural elements.Also, the effect of using high-performance concrete with the method of reducing the water-to-cement ratio, as a method for maintenance of reinforced concrete structures, has been analyzed.So, the influence of the above rehabilitation methods for maintenance of reinforced concrete structures on the corrosion initiation time of reinforcement, crack initiation time and crack width of the concrete cover thickness, the service life of a reinforced concrete structure due to corrosion, and corrosion percentage of reinforcement have been investigated.For this purpose, all equations and connection between them for the corrosion phenomenon modeling (including corrosion initiation phase, corrosion propagation phase and cracking) is integrated, and the corrosion parameters are calculated and compared for the marine environmental conditions.The results indicated that, the end time of service life of a reinforced concrete structure due to corrosion (tf) increases 60.54% by applying the new reinforcement as a rehabilitation method.So, in concrete with a water-to-cement ratio of 0.35, the corrosion percentage of reinforcement in the new-reinforcement scenario has decreased by 15.60% compared to the no-repair scenario over 30 years.
{"title":"Rehabilitation of Corroded Reinforced Concrete Elements by Rebar Replacement","authors":"A. Farahani","doi":"10.22075/JRCE.2021.23237.1504","DOIUrl":"https://doi.org/10.22075/JRCE.2021.23237.1504","url":null,"abstract":"In this study, the replacement of corroded reinforcement with new reinforcement as a rehabilitation method is considered to reduce the impact of corrosion on the performance of reinforced concrete structural elements.Also, the effect of using high-performance concrete with the method of reducing the water-to-cement ratio, as a method for maintenance of reinforced concrete structures, has been analyzed.So, the influence of the above rehabilitation methods for maintenance of reinforced concrete structures on the corrosion initiation time of reinforcement, crack initiation time and crack width of the concrete cover thickness, the service life of a reinforced concrete structure due to corrosion, and corrosion percentage of reinforcement have been investigated.For this purpose, all equations and connection between them for the corrosion phenomenon modeling (including corrosion initiation phase, corrosion propagation phase and cracking) is integrated, and the corrosion parameters are calculated and compared for the marine environmental conditions.The results indicated that, the end time of service life of a reinforced concrete structure due to corrosion (tf) increases 60.54% by applying the new reinforcement as a rehabilitation method.So, in concrete with a water-to-cement ratio of 0.35, the corrosion percentage of reinforcement in the new-reinforcement scenario has decreased by 15.60% compared to the no-repair scenario over 30 years.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"68 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73823044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-13DOI: 10.22075/JRCE.2021.23198.1501
S. M. Khatami, Hamed Momenabadi
Terrorist blast attacks have increased in recent years. Hand bombs are one of the means for terrorist operations because of their dangerous progressive damages. In this paper, a full coupled numerical method is adopted to study the dynamic response of a metro tunnel in the sandy loam. The numerical model is developed using LS-DYNA and will be able to present a realistic behavior for the physics of this phenomenon. In the current study, the ALE method has been used. The air, explosive charge, and soil are considered as ALE’s parts; while, the structure of the tunnel has Lagrangian mesh. Two paths have been studied in the longitudinal and the circular directions for assessing tunnel lining safety. In the free-field state, the accuracy of the model is verified by comparing the peak pressure and acceleration in the soil with the empirical predictions available in the literature. The safety assessment has been done according to blast vibration criteria. The tunnel would not be safe, as per the PPV standard, under the condition of w=500kg and R=4m. Tunnel crowns are the most vulnerable areas while the peak particle velocity is 19cm/s with maximum permanent vertical deformation.
{"title":"A Full Coupled Numerical Method for Dynamic Response of Metro Tunnel Subjected to Surface Explosion","authors":"S. M. Khatami, Hamed Momenabadi","doi":"10.22075/JRCE.2021.23198.1501","DOIUrl":"https://doi.org/10.22075/JRCE.2021.23198.1501","url":null,"abstract":"Terrorist blast attacks have increased in recent years. Hand bombs are one of the means for terrorist operations because of their dangerous progressive damages. In this paper, a full coupled numerical method is adopted to study the dynamic response of a metro tunnel in the sandy loam. The numerical model is developed using LS-DYNA and will be able to present a realistic behavior for the physics of this phenomenon. In the current study, the ALE method has been used. The air, explosive charge, and soil are considered as ALE’s parts; while, the structure of the tunnel has Lagrangian mesh. Two paths have been studied in the longitudinal and the circular directions for assessing tunnel lining safety. In the free-field state, the accuracy of the model is verified by comparing the peak pressure and acceleration in the soil with the empirical predictions available in the literature. The safety assessment has been done according to blast vibration criteria. The tunnel would not be safe, as per the PPV standard, under the condition of w=500kg and R=4m. Tunnel crowns are the most vulnerable areas while the peak particle velocity is 19cm/s with maximum permanent vertical deformation.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85512456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-13DOI: 10.22075/JRCE.2021.24176.1536
M. J. Al-Waily, M. S. Al-Qaisi
The current investigation used 16 model tests with two alternative foundation shapes, one strip and the other square, for a total of eight model tests for each foundation type. A model test was conducted only on natural soils to evaluate the two types of foundation and both circumstances of improvement utilizing RAP. The model square footing was laid on a layer of (RAP), with the varied widths (1.25B and 1.75B) and different thicknesses (0.25 B, 0.50 B, and 0.75 B in which B=footing width). Six model tests are tested in two widths (1.25B and 2.50B) in model strip footing treated (RAP), and three thicknesses (0.50B, 1B, and 1.5B) in each width are done. The settlement improvement factor was utilized to show the (RAP) layer's influence.The data suggested that the (RAP) layer beneath the foundations influenced settlement significantly. The RAP material in a square footing with a depth of 0.75 B offered the most efficient settlement reduction, with the lowest settlement improvement factor of all model tests. A model test was run with a RAP width of B and a depth of 0.25 B. It was discovered that RAP soil treatment reduced settlement by 0.34, implying that treated soil settled by 34% less than untreated soil.
{"title":"Evaluation of RAP Engineering Characteristics in Layered Soil","authors":"M. J. Al-Waily, M. S. Al-Qaisi","doi":"10.22075/JRCE.2021.24176.1536","DOIUrl":"https://doi.org/10.22075/JRCE.2021.24176.1536","url":null,"abstract":"The current investigation used 16 model tests with two alternative foundation shapes, one strip and the other square, for a total of eight model tests for each foundation type. A model test was conducted only on natural soils to evaluate the two types of foundation and both circumstances of improvement utilizing RAP. The model square footing was laid on a layer of (RAP), with the varied widths (1.25B and 1.75B) and different thicknesses (0.25 B, 0.50 B, and 0.75 B in which B=footing width). Six model tests are tested in two widths (1.25B and 2.50B) in model strip footing treated (RAP), and three thicknesses (0.50B, 1B, and 1.5B) in each width are done. The settlement improvement factor was utilized to show the (RAP) layer's influence.The data suggested that the (RAP) layer beneath the foundations influenced settlement significantly. The RAP material in a square footing with a depth of 0.75 B offered the most efficient settlement reduction, with the lowest settlement improvement factor of all model tests. A model test was run with a RAP width of B and a depth of 0.25 B. It was discovered that RAP soil treatment reduced settlement by 0.34, implying that treated soil settled by 34% less than untreated soil.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"80 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80793418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-13DOI: 10.22075/JRCE.2021.23343.1508
Sahil Khan, K. Nagarajan, R. Narwade
The use of concrete as parent material is now an old technique, but it is widely used today due to its unique characteristics. India has witnessed development in the construction field from Harappa civilization to the British era for many years. Even after independence, in 1947, India has advanced in construction techniques in concerning time. However, improper management, design, and ignorance of repairs and rehabilitation of structure cause the collapse of buildings which causes many deaths to occur every year in Mumbai and throughout the country. But the people living in dilapidated buildings risk their lives. Many people are constrained to live in them due to various reasons like skyrocketing rise in real estate prices, fear of losing their houses after vacating for redevelopment projects. Repair and rehabilitation are significant for preserving the structure’s capacity and increasing its performance capacity, which deteriorates due to aging factors, environmental factors. This paper aims to determine the various risks involved in dilapidated buildings by studying various health and safety factors that affect the age of the building. This research also focuses on scrutinizing various problems faced by the residing people in dilapidated buildings. The methodology adopted in this research is by doing unstructured interviews with a questionnaire survey of tenants, performing field surveys of various structures in the study area, and segregating the buildings based on the building’s various safety and hygienic conditions. The result shows the DI (Dilapidation index) score, which is done based on the comfort level of tenants.
{"title":"Risk assessment and challenges faced in repairs and rehabilitation of dilapidated buildings.","authors":"Sahil Khan, K. Nagarajan, R. Narwade","doi":"10.22075/JRCE.2021.23343.1508","DOIUrl":"https://doi.org/10.22075/JRCE.2021.23343.1508","url":null,"abstract":"The use of concrete as parent material is now an old technique, but it is widely used today due to its unique characteristics. India has witnessed development in the construction field from Harappa civilization to the British era for many years. Even after independence, in 1947, India has advanced in construction techniques in concerning time. However, improper management, design, and ignorance of repairs and rehabilitation of structure cause the collapse of buildings which causes many deaths to occur every year in Mumbai and throughout the country. But the people living in dilapidated buildings risk their lives. Many people are constrained to live in them due to various reasons like skyrocketing rise in real estate prices, fear of losing their houses after vacating for redevelopment projects. Repair and rehabilitation are significant for preserving the structure’s capacity and increasing its performance capacity, which deteriorates due to aging factors, environmental factors. This paper aims to determine the various risks involved in dilapidated buildings by studying various health and safety factors that affect the age of the building. This research also focuses on scrutinizing various problems faced by the residing people in dilapidated buildings. The methodology adopted in this research is by doing unstructured interviews with a questionnaire survey of tenants, performing field surveys of various structures in the study area, and segregating the buildings based on the building’s various safety and hygienic conditions. The result shows the DI (Dilapidation index) score, which is done based on the comfort level of tenants.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"75 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76698848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-01DOI: 10.22075/JRCE.2021.22232.1468
G. Shafabakhsh, A. Rahmani, M. Sadeghnejad
In recent decades, with increasing in traffic load, a great portion of repair and maintenance budget is being spent on improving the pavement failure. Asphalt fatigue, which is due to traffic cyclic loading, is one of the most important failure in asphalt pavements, therefore, increasing fatigue life in pavement can lead to a decrease in repair and maintenance budget. As a result, replacing or adding some additives to improve the fatigue behavior of the asphalt mixture, can help to reduce the fatigue cracks and increase the mixture life. In this research, fatigue behavior of asphalt mixture has been analyzed by using four point bending beam test with constant strain method on control and modified specimens with cement, coal waste and lime as filler. Fatigue behavior has been assessed at 2 strain 400 and 600 with replacing cement, coal waste and lime as the filler in the mixture. Results show that using each of 3 fillers at both strain state, leads to an improvement in fatigue life of asphalt mixture. Analyzing the results show that using above fillers could be used as an approach to improve the pavement’s function. Quantitatively, the three fillers, cement, coal waste and lime improved the fatigue life compared to the witness specimen by 75%, 55% and 8.2% at strain state of 400 and 107%, 72% and 7.1% at strain state of 600, respectively. Using coal waste can reduce the environmental issues due to coal waste deposits in addition to improving the fatigue life of asphalt mixture.
{"title":"Evaluation the Effect of Different Kind of Waste and Mineral Filler on the Fatigue Life of Asphalt Mixtures with Dissipated Energy Method","authors":"G. Shafabakhsh, A. Rahmani, M. Sadeghnejad","doi":"10.22075/JRCE.2021.22232.1468","DOIUrl":"https://doi.org/10.22075/JRCE.2021.22232.1468","url":null,"abstract":"In recent decades, with increasing in traffic load, a great portion of repair and maintenance budget is being spent on improving the pavement failure. Asphalt fatigue, which is due to traffic cyclic loading, is one of the most important failure in asphalt pavements, therefore, increasing fatigue life in pavement can lead to a decrease in repair and maintenance budget. As a result, replacing or adding some additives to improve the fatigue behavior of the asphalt mixture, can help to reduce the fatigue cracks and increase the mixture life. In this research, fatigue behavior of asphalt mixture has been analyzed by using four point bending beam test with constant strain method on control and modified specimens with cement, coal waste and lime as filler. Fatigue behavior has been assessed at 2 strain 400 and 600 with replacing cement, coal waste and lime as the filler in the mixture. Results show that using each of 3 fillers at both strain state, leads to an improvement in fatigue life of asphalt mixture. Analyzing the results show that using above fillers could be used as an approach to improve the pavement’s function. Quantitatively, the three fillers, cement, coal waste and lime improved the fatigue life compared to the witness specimen by 75%, 55% and 8.2% at strain state of 400 and 107%, 72% and 7.1% at strain state of 600, respectively. Using coal waste can reduce the environmental issues due to coal waste deposits in addition to improving the fatigue life of asphalt mixture.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81768787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-28DOI: 10.22075/JRCE.2021.21898.1456
Hossein Razzaghi, R. Madandoust, Hassan Aghabarati
This paper aimed at assessing the in-situ strength of steel fibre reinforced concrete containing recycled coarse aggregate (RCA) using the correlation between ultrasonic and point load tests. The mechanical properties of recycled aggregate concrete can be improved by adding fibres in concrete mixes. On the other hand, the importance of strength estimation of existing concrete at the building site has led to use non-destructive and partially testing methods. So, in this research, the compressive strength of wet and dry cured mixes made with RCA and steel fibre (SF) at 1.5% by volume was evaluated by mean of point load test (PLT) and ultrasonic method. As per the experimental outputs, the standard deviation (SD) values increased up to 20% by increasing the substitution amount of natural aggregate with RCA from 50% to 100%. In addition, the point load index (PLI) of wet cured concrete mixes was obtained averagely about 14.3% more than that of dry cured concrete mixes. Furthermore, the strength estimation of conventional concrete or fibre reinforced recycled aggregate concrete at different ages was carried out using a two-variable equation between ultrasonic pulse velocity (UPV) and PLI values.
{"title":"Strength assessment of steel fibre reinforced recycled aggregate concrete by means of correlation between ultrasonic and point load tests","authors":"Hossein Razzaghi, R. Madandoust, Hassan Aghabarati","doi":"10.22075/JRCE.2021.21898.1456","DOIUrl":"https://doi.org/10.22075/JRCE.2021.21898.1456","url":null,"abstract":"This paper aimed at assessing the in-situ strength of steel fibre reinforced concrete containing recycled coarse aggregate (RCA) using the correlation between ultrasonic and point load tests. The mechanical properties of recycled aggregate concrete can be improved by adding fibres in concrete mixes. On the other hand, the importance of strength estimation of existing concrete at the building site has led to use non-destructive and partially testing methods. So, in this research, the compressive strength of wet and dry cured mixes made with RCA and steel fibre (SF) at 1.5% by volume was evaluated by mean of point load test (PLT) and ultrasonic method. As per the experimental outputs, the standard deviation (SD) values increased up to 20% by increasing the substitution amount of natural aggregate with RCA from 50% to 100%. In addition, the point load index (PLI) of wet cured concrete mixes was obtained averagely about 14.3% more than that of dry cured concrete mixes. Furthermore, the strength estimation of conventional concrete or fibre reinforced recycled aggregate concrete at different ages was carried out using a two-variable equation between ultrasonic pulse velocity (UPV) and PLI values.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80092778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-28DOI: 10.22075/JRCE.2021.23214.1502
G. Shafabakhsh, Hamed Momenabadi, S. M. Mirabdolazimi
Fatigue behavior of Asphalt pavement is dependent on different parameters, including the bitumen, Aggregate, and mixture design. This study aims to investigate the effects of different air void contents of asphalt mixes prepared using two common bitumen types in Iran, 60/70 and 85/100, and limestone as well as silica aggregates on the fatigue life of the asphalt mixes at 5℃. First, the optimal amount of bitumen was calculated for each aggregate using the Marshall test. Then, to determine the fatigue behavior of the asphalt samples, indirect tensile tests were performed with controlled stresses at the levels of 100, 200, and 300 kPa. The results indicated that the 60/70 bitumen sample had a longer fatigue life than the 85/100 bitumen sample. The effect of the changing the bitumen type from 60/70 to 85/100 on fatigue life is more noticeable than the effect of the changing the air void content. Furthermore, it was revealed that lime aggregates have a higher fatigue life in comparison to silica aggregates, and the influence of increasing the air void content on fatigue life reduction is larger than that of changing the aggregate type. Eventually, some models were proposed to describe the fatigue life of asphalt mixes with different materials and different air void contents based on experimental studies and numerical analyses.
{"title":"The experimental investigation of fatigue life of Hot Mix Asphalt with different air void contents, aggregate type and bitumen grade at low temperature","authors":"G. Shafabakhsh, Hamed Momenabadi, S. M. Mirabdolazimi","doi":"10.22075/JRCE.2021.23214.1502","DOIUrl":"https://doi.org/10.22075/JRCE.2021.23214.1502","url":null,"abstract":"Fatigue behavior of Asphalt pavement is dependent on different parameters, including the bitumen, Aggregate, and mixture design. This study aims to investigate the effects of different air void contents of asphalt mixes prepared using two common bitumen types in Iran, 60/70 and 85/100, and limestone as well as silica aggregates on the fatigue life of the asphalt mixes at 5℃. First, the optimal amount of bitumen was calculated for each aggregate using the Marshall test. Then, to determine the fatigue behavior of the asphalt samples, indirect tensile tests were performed with controlled stresses at the levels of 100, 200, and 300 kPa. The results indicated that the 60/70 bitumen sample had a longer fatigue life than the 85/100 bitumen sample. The effect of the changing the bitumen type from 60/70 to 85/100 on fatigue life is more noticeable than the effect of the changing the air void content. Furthermore, it was revealed that lime aggregates have a higher fatigue life in comparison to silica aggregates, and the influence of increasing the air void content on fatigue life reduction is larger than that of changing the aggregate type. Eventually, some models were proposed to describe the fatigue life of asphalt mixes with different materials and different air void contents based on experimental studies and numerical analyses.","PeriodicalId":52415,"journal":{"name":"Journal of Rehabilitation in Civil Engineering","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81993934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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