BIOASPHALT AS RAP REJUVENATORAND ASBUTON MODIFIER IN HOT MIX ASPHALT

• Main Author: Verani Rouly Sihombing, Atmy
• Format: Dissertations
• Language: Indonesia
• Subjects: Teknik sipil
• Online Access: https://digilib.itb.ac.id/gdl/view/79268
• Institution: Institut Teknologi Bandung

Indonesia still uses asphalt as a material for road construction and maintenance. According to data from the Director-General of Bina Marga KemenPUPR, 2019 asphalt needs are 1.3 - 1.5 million tons/year, of which 70% will still rely on imports. Efforts that can be made to overcome these imports are by utilizing Reclaimed Asphalt Pavement (RAP) or waste from the old pavement and optimally utilizing natural resources in Indonesia, namely Asbuton. In its use, both RAP and Asbuton, especially granular Asbuton (ASB) require rejuvenator/modifier. It's just that until now, the rejuvenating materials used in Indonesia still rely on imported rejuvenating ingredients, so the use of RAP and ASB are considered not effective in addressing domestic asphalt needs. For this reason, a local rejuvenating agent needs to be found to make effective use of RAP and ASB. Bio-asphalt as asphalt is produced from non-food ingredients (agricultural residues and plantation waste) or biomass containing lignin, where one of its functions can be used as a rejuvenating material. One of the lignin-containing biomass found in Indonesia is coconut shell waste, which reaches 360 thousand tons annually. With a lignin content of 29.4%, the coconut shell is considered to have considerable potential as a local rejuvenating ingredient. To test its potential, coconut shell bioaspal (BTK) needs to be tested for its performance as a rejuvenator / ingredient for asphalt mixtures containing RAP and as a modifier for asphalt mixtures containing ASB based on criteria for asphalt mixture resistance to fatigue. Bio-asphalt used in this research is bio-asphalt from coconut shells (BTK) and Bitutech RAP (BT). The use of bio asphalt as modifier in this study was reviewed by adding bio asphalt to RAP bitumen and Asbuton B 50/30 (ASB), by looking at the characteristics of asphalt before and after adding bio-asphalt based on chemical structure testing using FTIR, asphalt morphology with SEM and EDX, asphalt rheology and mechanical asphalt rheology with DSR temperature sweep and frequency sweep. The use of bio asphalt was also investigated by looking at its effect as a modifier/rejuvenator for AC-WC hot asphalt mixture containing RAP with variations in RAP content: 10%; 20%, and 30%, as well as AC-WC mixtures containing ASB with content variations: 7%; 11%, and 15%. Asphalt mixture testing is done by the Marshall test, Smix uses UMATTA in OBC conditions, the results are then compared with the results of the calculation of the Nottingham and Shell models and also develops the Smix model. The fatigue resistance review is carried out using a Four-Point Bending Test (4PBT) in OBC conditions, the results are then compared with the results of the calculation of the Shell model and Austroad model and the development of the fatigue resistance (Nf) model. The test results of bio-asphalt on RAP are 1). Based on the characteristics of asphalt, bio-asphalt (BTK and BT) can be used as a rejuvenating agent for RAP bitumen, 23% BTK content and 17% BT (from RAP bitumen weight) that can meet performance pen 60/70; 2). Based on the characteristics of the asphalt mixture of AC-WC, the addition of bio-asphalt as a modifier/rejuvenator in AC-WC mixtures containing RAP up to 30%, can produce OBC that meet the criteria of the AC-WC mixture, this shows that bio-asphalt can rejuvenate RAP bitumen; 3). Based on Smix testing, the performance of bioaspal in AC-WC mixture containing RAP, shown by the Smix produced even though the number of RAP increased, this indicates the rejuvenation of RAP bitumen, so that bonding occurs between bitumen and mixed aggregate; 4). Based on the fatigue life, both bio-asphalt produced a mixture of AC-WC containing RAP with a longer fatigue life compared to AC-WC control. The results of bio-asphalt test on ASB are 1). Based on the characteristics of asphalt, bio-asphalt (BTK and BT) can be used as a modifier for ASB bitumen, ASB bitumen performance can achieve pen 60/70 performance with 6.5% BTK and 8% BT from ASB bitumen weight; 2). Based on the characteristics of the asphalt mixture, only BTK can be used as a modifier on AC-WC mixtures containing up to 15% ASB, which is indicated by the resulting OBC that meets the criteria of ACWC mixture; 3) Smix values are produced even though the ASB number increased, shows that BTK can be used as a modifier in AC-WC mixture containing ASB; 4) Based on Marshall and UMATTA testing, it is known that the best mixture design for ACWC + BTK + ASB is design 2 with an optimum ASB content of 7% and bioasphalt content 25% of the weight of ASB; 5) Based on the fatigue resistance test, a mixture of AC-WC + BTK + ASB gives a longer fatigue life compared to AC-WC control. Smix and Nf models for each mixture are 1). AC-WC + BTK + RAP, Smix is a function of Sbit, Tuji, VMA, and RAP with adj R2 = 0.97 and the Nf model is a function of Smix, strain, and RAP with adj R2 = 0.87; 2). AC-WC + BT + RAP, Smix is a function of Sbit, Tuji, VIM, and RAP with adj R2 = 0.93 and Nf is a function of Smix, strain, and RAP with adj R2 = 0.88; 3). AC-WC + BTK + ASB, Smix is a function of Sbit, Tuji, VMA, and RAP with adj R2 = 0.97 and Nf is a function of Smix and strain with adj R2 = 0.69, with a 95% confidence level (? = 0.05). The limitation of the resilient modulus prediction model is the minimum value of asphalt stiffness of 5 MPa, the maximum amount of RAP 30% and ASBUTON B 50/30 15% of the weight of the asphalt mixture, the percentage of BTK 23%, BT 17% of the weight of asphalt RAP and BTK 25% of the weight ASB, the smix value obtained from the UMATTA test tool with a 250 ms pulse width loading and 3000 ms pulse repetition. Limitation of fatigue resistance prediction models is testing done with 4PBT, a controlled strain between 300 ?? to 500 ??, temperature 20 ° C, Smix based on lab tests for mixtures with RAP and based on Smix models for mixes with ASB.