logging in or signing up pavement recycling sungadi Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 672 Category: Education License: All Rights Reserved Like it (2) Dislike it (0) Added: October 23, 2009 This Presentation is Public Favorites: 1 Presentation Description No description available. Comments Posting comment... By: sungadi (17 month(s) ago) send me all your mail ids' Saving..... Post Reply Close Saving..... Edit Comment Close By: onsori (17 month(s) ago) good job Saving..... Post Reply Close Saving..... Edit Comment Close By: navingoyal2010 (21 month(s) ago) Good presentation. Pl send me the same or allow me to download. regards. Navin Saving..... Post Reply Close Saving..... Edit Comment Close By: psreashma (31 month(s) ago) Sir, Can you make this presentation in downloaded format. thanking you, Reashma P.S. Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript Slide 1: PAVEMENT RECYCLING & DESIGN OF CENTRAL PLANT HOT MIX ASPHALT Presented by, S.Sreenivasulu (R.NO.07410415) Under the guidance of, Dr .Ryntathiang L.T Department of civil Engineering Indian Institute of Technology – Guwahati. PAVEMENT RECYCLING & DESIGN OF Life cycle costs : Life cycle costs When to Recycle : When to Recycle Pavement at end of design life Fatigue and block cracking Oxidized Raveling of thermal cracks-potholes Benefits of Recycling : Benefits of Recycling Reuses and conserves Non- renewable natural resources Preservation of environment and Reduction in land filling Energy conservation/ Reduction in truck traffic Reduction in user delays during construction Improved pavement and structural section physical properties Cost savings over traditional methods Recycling methods : Recycling methods Hot in-place recycling : Hot in-place recycling Process: heat the pavement and remove the top surface Add the calculated fresh aggregate and binder. Mix and compact the material to the required thickness Merits consumes less time, less cost, no lead. least disruption to traffic De-merits Requires bulky Machinery Hot central plant recycling : Hot central plant recycling process: RAP is combined with required quantity of bituminous binder, and fresh aggregates in a hot mix plant. The resultant mix is heated to an elevated temperature and mixed thoroughly. The hot mix is transported to paving site, placed, and compacted to the required compaction level. Merits Good quality control Less workspace Demerit Needs proper storing of RAP Cold in place recycling : Cold in place recycling Pavement is scarified, RAP is crushed to a required gradation and required fresh aggregate& binder is added (cold form) hauling cost is considerably low. Air quality problems are negligible Bulky machinery, lane needs to be closed for sufficient time so that lane can be cured Slide 15: Cold central plant recycling : Cold central plant recycling Similar to hot central plant recycling except that no heat is supplied Precise control on the mixing time is important Over-mixing may cause premature breaking of emulsified bitumen under-mixing results in insufficient coating of aggregates CASE STUDY : CASE STUDY pavement design with central plant hot mix recycled asphalt mixes. Two RAP samples are collected at Kanpur city and the recycled mix is prepared. Recycled mix is compared with virgin mix for marshal values, creep and fatigue performances. Cost comparison is made. Laboratory investigation : Laboratory investigation The quantity of old aggregates and new aggregates are to be adjusted in such a way that the resultant gradation of aggregates conforms to the specified gradation. The quantity of the aged asphalt binder, virgin asphalt binder and the rejuvenator, if any, are to be adjusted in such a way that the resultant viscosity becomes equal to the desirable viscosity at operating temperature. The total quantity of asphalt binder should be adjusted in such a way that it satisfies the desired asphalt binder quantity of the target mix. Slide 26: The other volumetric and strength parameters of the mix should also be satisfied. The RAP samples are collected, cleaned, bitumen is extracted with CBE, aggregate proportioned, and mixed with virgin asphalt binder and new aggregates, for various target bitumen contents. Standard Marshall testing is conducted for estimation of the possible optimal binder content. Further, creep and fatigue tests are performed on the recycled samples in order to asses their performance. The same tests are conducted for virgin mixes, with same specification, in order to have a comparative idea of mix performance. SCHEMATIC PLAN OF THE WHOLE STUDY : SCHEMATIC PLAN OF THE WHOLE STUDY Mix preparation : Mix preparation Process1: old binder+ virgin binder= homogenous mixture of required viscosity. This mixture+ old aggregates+ fresh aggregates= recycled mix Prcoess2: (broken RAP + fresh aggregates ---heated @high temperature and for this known amount of virgin binder are added) = recycled mix Slide 30: Viscosity mixing rule: used to estimate proportion between the virgin and aged binder Where, Represent viscosity of target mix, aged and virgin binder at the reference temperature. Represent fraction of aged and virgin binder, respectively Asphalt institute recommended… : Asphalt institute recommended… Properties of extracted & virgin binder : Properties of extracted & virgin binder MARSHAL TEST : MARSHAL TEST Approximate binder demand for SDBC estimated as 5.5% Marshal samples are prepared for bitumencontentsof4.5%,5%,5.5%,6%,6.5% It may be noted that as the target binder content changes, the constituent proportions also gets changed and needs recalculation with every time. 175 blows -24h curing- kept in water bath @60 C for 30 minutes and then tested . Slide 34: Tests are conducted on virgin mix and found that the marshal criteria is ranging in between 5% to 6.4%. So choose 5.5% as optimum content. For the recycled mixes, Marshall stability and flow values almost remained within the permissible ranges and even comparable to the virgin mix. It is only the volumetric parameter values that seem to go out of the range. Schematic representation of virgin mix results : Schematic representation of virgin mix results CREEP TEST : CREEP TEST Static creep test is one of the tests that can characterize rutting potential of a mix. This involves loading and unloading for a period of 1 h each at a temperature of 40 C. The samples for creep test are prepared in similar way the samples are prepared for Marshall testing. Each sample is tested after curing for 24 h. calculated amount of load is placed at the end of the loading frame such that stress of 0.1 MPa is developed in the sample. After a period of1 h, the load is removed. The displacements are noted at different time intervals using dial gauges over the entire period. DEFORMATION VS. TIME : DEFORMATION VS. TIME VARIATION OF RECOVERABLE STRAIN WITH BINDER CONTENT : VARIATION OF RECOVERABLE STRAIN WITH BINDER CONTENT DISCUSSION… : DISCUSSION… Recoverable strain gradually increases with the binder content and then again starts decreasing for all types of mixes. From Fig. 7 it is seen that for most of the mixes, maximum recoverable strain is observed between 5.5% and 6.0% of binder content. Further, the permanent and recoverable strain components are compared in Fig. 8 for all types of mixes at particular binder content, chosen as 5.5% in the present case. It is seen that even though permanent strain component in virgin mix is less, recoverable strain in recycled mix is comparable to that of virgin mix. CREEP PERFORMANCE@5.5%BITUMEN CONTENT : CREEP PERFORMANCE@5.5%BITUMEN CONTENT FATIGUE TEST : FATIGUE TEST Beam fatigue test is one of the tests that can characterize the fatigue behavior of the mix. In this case a binder content of 5.5% is chosen for fatigue testing for all types of mixes. Constant strain amplitude fatigue testing is carried out to characterize fatigue behavior of recycled mixes. Fatigue testing machine consists of a motor, cam, load cell, LVDT, beam holding arrangement and a data acquisition system. Motor is used to apply sinusoidal loading on the specimen. The cam arrangement is used to impart displacement to the specimen, which in turn varies the strain in the beam. A load cell is used in measuring the load applied and a LVDT is used to measure displacement. Since constant strain amplitude fatigue test is carried out, the maximum displacement is kept constant for the entire period of testing on a particular beam. The beam holding arrangement is used to fix the beam rigidly in place. A photographic view of the setup is given in Fig. 9. Slide 43: Asphalt mix is prepared and poured into the mould (length 380 mm, breadth 78 mm) in three layers and it is compacted with 175 blows with standard Marshall Hammer. These beams are tested for fatigue performance after 24 h of curing. Each beam is fixed to the fatigue testing machine and sinusoidal loading is applied. Load corresponding to half the initial load is noted as failure load and corresponding number of repetitions is also noted. Similar procedure is repeated for other test samples at different strain levels to develop the fatigue curve. Temperature during test is maintained 30 ± 2 C. BITUMEN FATIGUE TESTING MACHINE : BITUMEN FATIGUE TESTING MACHINE GENERAL REGRESSION BASED FATIGUE EQUATION : GENERAL REGRESSION BASED FATIGUE EQUATION Where, N = number of load repetitions the beam can sustain till failure = tensile strain = regression coefficients Discussions… : Discussions… From Fig. 10 it can be seen that at lower strain levels, the fatigue lives of the recycled mixes are better or similar to that of virgin SDBC mix. However, at higher strain level, the opposite trend is observed. Fatigue performance of S2-T1 is observed to be poorest of all other mixes. The stiffness values of Sample 1 recycled mixes are observed (refer Table 5) to be higher than virgin mix. For Sample 2 it is observed to be reverse. Fatigue performance of mixes : Fatigue performance of mixes Discussions.. : Discussions.. From Fig. 10 it can be seen that at lower strain levels, the fatigue lives of the recycled mixes are better or similar to that of virgin SDBC mix. However, at higher strain level, the opposite trend is observed. Fatigue performance of S2-T1 is observed to be poorest of all other mixes. The stiffness values of Sample 1 recycled mixes are observed (refer Table 5) to be higher than virgin mix. For Sample 2 it is observed to be reverse. Pavement design &comparison : Pavement design &comparison For performing pavement design a suitable shift factor, derived from long term pavement performance data, needs to be adopted. Different shift-factor values are suggested by various researchers. The shift factor for asphalt pavement can even vary between 5 and 700. In absence of field performance data of the recycled mixes developed, a value of 100 is chosen as shift factor for all the fatigue equations for comparison of various pavement designs. The values of k0 of fatigue Eq. for various mixes are accordingly modified Slide 50: For the present pavement design, a three layer pavement section is assumed, made up of asphalt surfacing, unbound granular layer and subgrade. Literature suggests that Poisson’s ratio generally ranges from 0.35 to 0.5 for asphalt layer, 0.2 to 0.45 for unbound granular layer and 0.3 to 0.5 for clayey subgrade. Thus, in the present case, typical Poisson’s ratio values as 0.35, 0.3 and 0.3 are chosen for asphalt surfacing, unbound granular layer and subgrade, respectively. The stiffness moduli of granular layer and subgrade have been assumed as 150 MPa and 50 MPa, respectively. Slide 51: The design traffic is assumed to be 20 million standard axles Using the fatigue equations, the allowable strains are obtained for the design traffic. For a given thickness of granular layer, some tentative thickness value of bituminous surfacing layer is assumed and the tensile strain value is calculated Now, it is possible to compare the material cost of the construction of asphalt layer made up of recycled mix and virgin mix. Designed thickness of SDBC : Designed thickness of SDBC Rate analysis of virgin SDBC mix : Rate analysis of virgin SDBC mix Conclusions.. : Conclusions.. cost of construction with recycled mix could be economical compared to virgin mix. Percentage saving in the present example problem varied between12.1% and 54.6% for different mixes. Bituminous pavement recycling technology is not yet a popular in India. USA 33 million , 0.84million tons in Sweden, 7.3 million tons in Germany, 0.53 million tons in Denmark, 20 million tons in Japan. Reference : Reference Pavement design with central plant hot mix recycled asphalt mixes - K.Aravind, Animeshdas Pavement recycling by Wilson&Co.Ltd. A Work shop on pavement recycling at IIT Kanpur during Dec’05. Slide 57: QUESTIONS…? You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
pavement recycling sungadi Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 672 Category: Education License: All Rights Reserved Like it (2) Dislike it (0) Added: October 23, 2009 This Presentation is Public Favorites: 1 Presentation Description No description available. Comments Posting comment... By: sungadi (17 month(s) ago) send me all your mail ids' Saving..... Post Reply Close Saving..... Edit Comment Close By: onsori (17 month(s) ago) good job Saving..... Post Reply Close Saving..... Edit Comment Close By: navingoyal2010 (21 month(s) ago) Good presentation. Pl send me the same or allow me to download. regards. Navin Saving..... Post Reply Close Saving..... Edit Comment Close By: psreashma (31 month(s) ago) Sir, Can you make this presentation in downloaded format. thanking you, Reashma P.S. Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript Slide 1: PAVEMENT RECYCLING & DESIGN OF CENTRAL PLANT HOT MIX ASPHALT Presented by, S.Sreenivasulu (R.NO.07410415) Under the guidance of, Dr .Ryntathiang L.T Department of civil Engineering Indian Institute of Technology – Guwahati. PAVEMENT RECYCLING & DESIGN OF Life cycle costs : Life cycle costs When to Recycle : When to Recycle Pavement at end of design life Fatigue and block cracking Oxidized Raveling of thermal cracks-potholes Benefits of Recycling : Benefits of Recycling Reuses and conserves Non- renewable natural resources Preservation of environment and Reduction in land filling Energy conservation/ Reduction in truck traffic Reduction in user delays during construction Improved pavement and structural section physical properties Cost savings over traditional methods Recycling methods : Recycling methods Hot in-place recycling : Hot in-place recycling Process: heat the pavement and remove the top surface Add the calculated fresh aggregate and binder. Mix and compact the material to the required thickness Merits consumes less time, less cost, no lead. least disruption to traffic De-merits Requires bulky Machinery Hot central plant recycling : Hot central plant recycling process: RAP is combined with required quantity of bituminous binder, and fresh aggregates in a hot mix plant. The resultant mix is heated to an elevated temperature and mixed thoroughly. The hot mix is transported to paving site, placed, and compacted to the required compaction level. Merits Good quality control Less workspace Demerit Needs proper storing of RAP Cold in place recycling : Cold in place recycling Pavement is scarified, RAP is crushed to a required gradation and required fresh aggregate& binder is added (cold form) hauling cost is considerably low. Air quality problems are negligible Bulky machinery, lane needs to be closed for sufficient time so that lane can be cured Slide 15: Cold central plant recycling : Cold central plant recycling Similar to hot central plant recycling except that no heat is supplied Precise control on the mixing time is important Over-mixing may cause premature breaking of emulsified bitumen under-mixing results in insufficient coating of aggregates CASE STUDY : CASE STUDY pavement design with central plant hot mix recycled asphalt mixes. Two RAP samples are collected at Kanpur city and the recycled mix is prepared. Recycled mix is compared with virgin mix for marshal values, creep and fatigue performances. Cost comparison is made. Laboratory investigation : Laboratory investigation The quantity of old aggregates and new aggregates are to be adjusted in such a way that the resultant gradation of aggregates conforms to the specified gradation. The quantity of the aged asphalt binder, virgin asphalt binder and the rejuvenator, if any, are to be adjusted in such a way that the resultant viscosity becomes equal to the desirable viscosity at operating temperature. The total quantity of asphalt binder should be adjusted in such a way that it satisfies the desired asphalt binder quantity of the target mix. Slide 26: The other volumetric and strength parameters of the mix should also be satisfied. The RAP samples are collected, cleaned, bitumen is extracted with CBE, aggregate proportioned, and mixed with virgin asphalt binder and new aggregates, for various target bitumen contents. Standard Marshall testing is conducted for estimation of the possible optimal binder content. Further, creep and fatigue tests are performed on the recycled samples in order to asses their performance. The same tests are conducted for virgin mixes, with same specification, in order to have a comparative idea of mix performance. SCHEMATIC PLAN OF THE WHOLE STUDY : SCHEMATIC PLAN OF THE WHOLE STUDY Mix preparation : Mix preparation Process1: old binder+ virgin binder= homogenous mixture of required viscosity. This mixture+ old aggregates+ fresh aggregates= recycled mix Prcoess2: (broken RAP + fresh aggregates ---heated @high temperature and for this known amount of virgin binder are added) = recycled mix Slide 30: Viscosity mixing rule: used to estimate proportion between the virgin and aged binder Where, Represent viscosity of target mix, aged and virgin binder at the reference temperature. Represent fraction of aged and virgin binder, respectively Asphalt institute recommended… : Asphalt institute recommended… Properties of extracted & virgin binder : Properties of extracted & virgin binder MARSHAL TEST : MARSHAL TEST Approximate binder demand for SDBC estimated as 5.5% Marshal samples are prepared for bitumencontentsof4.5%,5%,5.5%,6%,6.5% It may be noted that as the target binder content changes, the constituent proportions also gets changed and needs recalculation with every time. 175 blows -24h curing- kept in water bath @60 C for 30 minutes and then tested . Slide 34: Tests are conducted on virgin mix and found that the marshal criteria is ranging in between 5% to 6.4%. So choose 5.5% as optimum content. For the recycled mixes, Marshall stability and flow values almost remained within the permissible ranges and even comparable to the virgin mix. It is only the volumetric parameter values that seem to go out of the range. Schematic representation of virgin mix results : Schematic representation of virgin mix results CREEP TEST : CREEP TEST Static creep test is one of the tests that can characterize rutting potential of a mix. This involves loading and unloading for a period of 1 h each at a temperature of 40 C. The samples for creep test are prepared in similar way the samples are prepared for Marshall testing. Each sample is tested after curing for 24 h. calculated amount of load is placed at the end of the loading frame such that stress of 0.1 MPa is developed in the sample. After a period of1 h, the load is removed. The displacements are noted at different time intervals using dial gauges over the entire period. DEFORMATION VS. TIME : DEFORMATION VS. TIME VARIATION OF RECOVERABLE STRAIN WITH BINDER CONTENT : VARIATION OF RECOVERABLE STRAIN WITH BINDER CONTENT DISCUSSION… : DISCUSSION… Recoverable strain gradually increases with the binder content and then again starts decreasing for all types of mixes. From Fig. 7 it is seen that for most of the mixes, maximum recoverable strain is observed between 5.5% and 6.0% of binder content. Further, the permanent and recoverable strain components are compared in Fig. 8 for all types of mixes at particular binder content, chosen as 5.5% in the present case. It is seen that even though permanent strain component in virgin mix is less, recoverable strain in recycled mix is comparable to that of virgin mix. CREEP PERFORMANCE@5.5%BITUMEN CONTENT : CREEP PERFORMANCE@5.5%BITUMEN CONTENT FATIGUE TEST : FATIGUE TEST Beam fatigue test is one of the tests that can characterize the fatigue behavior of the mix. In this case a binder content of 5.5% is chosen for fatigue testing for all types of mixes. Constant strain amplitude fatigue testing is carried out to characterize fatigue behavior of recycled mixes. Fatigue testing machine consists of a motor, cam, load cell, LVDT, beam holding arrangement and a data acquisition system. Motor is used to apply sinusoidal loading on the specimen. The cam arrangement is used to impart displacement to the specimen, which in turn varies the strain in the beam. A load cell is used in measuring the load applied and a LVDT is used to measure displacement. Since constant strain amplitude fatigue test is carried out, the maximum displacement is kept constant for the entire period of testing on a particular beam. The beam holding arrangement is used to fix the beam rigidly in place. A photographic view of the setup is given in Fig. 9. Slide 43: Asphalt mix is prepared and poured into the mould (length 380 mm, breadth 78 mm) in three layers and it is compacted with 175 blows with standard Marshall Hammer. These beams are tested for fatigue performance after 24 h of curing. Each beam is fixed to the fatigue testing machine and sinusoidal loading is applied. Load corresponding to half the initial load is noted as failure load and corresponding number of repetitions is also noted. Similar procedure is repeated for other test samples at different strain levels to develop the fatigue curve. Temperature during test is maintained 30 ± 2 C. BITUMEN FATIGUE TESTING MACHINE : BITUMEN FATIGUE TESTING MACHINE GENERAL REGRESSION BASED FATIGUE EQUATION : GENERAL REGRESSION BASED FATIGUE EQUATION Where, N = number of load repetitions the beam can sustain till failure = tensile strain = regression coefficients Discussions… : Discussions… From Fig. 10 it can be seen that at lower strain levels, the fatigue lives of the recycled mixes are better or similar to that of virgin SDBC mix. However, at higher strain level, the opposite trend is observed. Fatigue performance of S2-T1 is observed to be poorest of all other mixes. The stiffness values of Sample 1 recycled mixes are observed (refer Table 5) to be higher than virgin mix. For Sample 2 it is observed to be reverse. Fatigue performance of mixes : Fatigue performance of mixes Discussions.. : Discussions.. From Fig. 10 it can be seen that at lower strain levels, the fatigue lives of the recycled mixes are better or similar to that of virgin SDBC mix. However, at higher strain level, the opposite trend is observed. Fatigue performance of S2-T1 is observed to be poorest of all other mixes. The stiffness values of Sample 1 recycled mixes are observed (refer Table 5) to be higher than virgin mix. For Sample 2 it is observed to be reverse. Pavement design &comparison : Pavement design &comparison For performing pavement design a suitable shift factor, derived from long term pavement performance data, needs to be adopted. Different shift-factor values are suggested by various researchers. The shift factor for asphalt pavement can even vary between 5 and 700. In absence of field performance data of the recycled mixes developed, a value of 100 is chosen as shift factor for all the fatigue equations for comparison of various pavement designs. The values of k0 of fatigue Eq. for various mixes are accordingly modified Slide 50: For the present pavement design, a three layer pavement section is assumed, made up of asphalt surfacing, unbound granular layer and subgrade. Literature suggests that Poisson’s ratio generally ranges from 0.35 to 0.5 for asphalt layer, 0.2 to 0.45 for unbound granular layer and 0.3 to 0.5 for clayey subgrade. Thus, in the present case, typical Poisson’s ratio values as 0.35, 0.3 and 0.3 are chosen for asphalt surfacing, unbound granular layer and subgrade, respectively. The stiffness moduli of granular layer and subgrade have been assumed as 150 MPa and 50 MPa, respectively. Slide 51: The design traffic is assumed to be 20 million standard axles Using the fatigue equations, the allowable strains are obtained for the design traffic. For a given thickness of granular layer, some tentative thickness value of bituminous surfacing layer is assumed and the tensile strain value is calculated Now, it is possible to compare the material cost of the construction of asphalt layer made up of recycled mix and virgin mix. Designed thickness of SDBC : Designed thickness of SDBC Rate analysis of virgin SDBC mix : Rate analysis of virgin SDBC mix Conclusions.. : Conclusions.. cost of construction with recycled mix could be economical compared to virgin mix. Percentage saving in the present example problem varied between12.1% and 54.6% for different mixes. Bituminous pavement recycling technology is not yet a popular in India. USA 33 million , 0.84million tons in Sweden, 7.3 million tons in Germany, 0.53 million tons in Denmark, 20 million tons in Japan. Reference : Reference Pavement design with central plant hot mix recycled asphalt mixes - K.Aravind, Animeshdas Pavement recycling by Wilson&Co.Ltd. A Work shop on pavement recycling at IIT Kanpur during Dec’05. Slide 57: QUESTIONS…?