scholarly journals Influence of Additives on Permanent Deformation and Resilient Modulus of Recycled Asphalt Concrete

2020 ◽  
Vol 26 (2) ◽  
pp. 159-175
Author(s):  
Mustafa Shakir Mahdi ◽  
Prof. saad Isa Sarsam

Tests were performed on asphalt concrete specimens with (101.6 mm in diameter and 101.6 mm in height), and the results were implemented for calculating permanent deformation and resilient modulus under repeated compressive stress with different levels of stresses (0.068, 0.138 and 0.206) MPa at 40 ºC. Two types of additives namely (carbon black-asphalt) and (SBR-asphalt) were tried as rejuvenators with three percentages of (0.5, 1 and 1.5) % by weight of asphalt cement along with two ratios of AC (1 and 2) % have been implemented as rejuvenator and blended with the reclaimed asphalt concrete. Aged materials were obtained from the site. 100% Reclaimed Asphalt Pavement material from the reclaimed mixture is implemented. A set of (3) specimens were prepared for every mixture; three specimens were tested under (repeated compressive stress) at each level of stress. The objective of this work was to study the effect of two types of additives (Styrene-Butadiene-Rubber (SBR) and carbon black) on the performance of recycled asphalt concrete mixture. It was concluded that the Resilient modulus (Mr) at (0.138 and 0.206) MPa stress level decreases by (14, 22 and 8) % and (22, 34 and 11) for reclaimed and recycle mixtures with (carbon black-asphalt and SBR-asphalt) respectively when compared with that at 0.068 MPa. Permanent deformation for recycled mixtures with (carbon black-asphalt and SBR-asphalt) increased by (65.9, 4.54) %, (146.6, 27.2) % and (79, 5.5) % at level of stresses (0.068, 0.138 and 0.206) MPa respectively when compared to reclaimed mixture.

2020 ◽  
Vol 1 (4) ◽  
pp. 1-6
Author(s):  
Saad Issa Sarsam

Asphalt concrete usually practices cracking and distress during its service life. However, recycling process as well as crack healing phenomena can enhance the physical properties and extend the pavement service life. This investigation is concerned with monitoring the microcrack healing of recycled asphalt concrete through its influence on deformation measurement under three testing techniques, repeated (compressive, tensile and shear stresses). Reclaimed asphalt concrete mixture was recycled with [carbon black-asphalt] and [Styrene Butadiene Rubber (SBR)-asphalt] rejuvenators. Specimens have been tested with the aid of the pneumatic repeated load system (PRLS). The repeated loading of the three testing techniques was terminated after 1000 load repetitions, and the specimens could heal by external heating at 60°C for 120 minutes. Specimens were returned to the (PRLS) and subjected to another run of repeated stresses application after healing. It was concluded that the deformation increases after recycling process while it declines after microcrack healing regardless of the testing technique adopted. The deformation declines by (31.8, 5.8 and 19)%, (43 ,49 and 24 )% and (44 ,10 and 13 )% under three level of repeated compressive stresses of (0.068, 0.138, and 0.206) MPa at (40 °C) after healing cycle for reclaimed and recycled mixture with (carbon black-asphalt) and (SBR-asphalt) respectively when compared with permanent deformation before the healing cycle. The permanent deformation under repeated punching shear and indirect tensile stresses declines after microcrack healing by (32, 26 and 25.7) % and (73, 78.7 and 78.2) % for reclaimed, recycled with (carbon black-asphalt) and recycled with (SBR-asphalt) mixtures respectively.


2019 ◽  
Vol 8 (4) ◽  
pp. 168-174
Author(s):  
Saad Issa Sarsam ◽  
Mohammed Chaloob Saleem

Utilizing reclaimed asphalt pavement (RAP) in new asphalt mixtures has increased in recent years because of its economic and environmental benefits. The flexibility of the recycled asphalt concrete (with cutback and emulsion) in terms of resilient modulus (Mr), rutting resistance, and permanent microstrain have been investigated in this work. Cylindrical specimens of 102 mm in diameter and 102 mm in height have been prepared from the recycled mixture after the short-term aging process. Specimens were subjected to 1200 repeated compressive stresses at (25) ºC. The vertical permanent microstrain was monitored through video capture. It was concluded that RAP mixture can hold the applied loading with minimal permanent deformation as compared to the recycled mixtures. The resilient modulus is lower by (24 and 39) % for mixes recycled with cutback and emulsion respectively as compared to that of RAP. The rate of strain (slope) increases by 11 % and 4 % when cutback and emulsion were implemented as recycling agent respectively as compared to that for RAP mixture.


2020 ◽  
Vol 39 (1) ◽  
pp. 81-90
Author(s):  
An Zhao ◽  
Xuan-Yu Shi ◽  
Shi-Hao Sun ◽  
Hai-Mo Zhang ◽  
Min Zuo ◽  
...  

2016 ◽  
Vol 700 ◽  
pp. 238-246 ◽  
Author(s):  
Dewi Sri Jayanti ◽  
Ramadhansyah Putra Jaya ◽  
Siti Aspalaili Mohamd Sharif ◽  
Norhidayah Abdul Hassan ◽  
Siti Nur Amiera Jeffry ◽  
...  

This study investigated the effects of adding various percentages of styrene–butadiene rubber (SBR) on the engineering properties and performance of asphaltic concrete. SBR was added into the mixture at 0%, 1%, 3%, and 5% on a mass-to-mass basis. Conventional bitumen used in this study was 80/100 PEN. The performances of SBR on the asphalt mixture properties were evaluated based on Marshall Stability, abrasion loss, resilient modulus, and dynamic creep test. Results indicated an improvement in the engineering properties and performance with the addition of SBR content. For instance, stability increased by 18.8% as the SBR content increased from 0% to 5%. Dynamic creep stiffness also increased by 46.2%. Similarly, the resilient modulus was also found to increase by approximately 84.6%.


2012 ◽  
Vol 19 (01) ◽  
pp. 1250003
Author(s):  
JIAN CHEN ◽  
YONGZHONG JIN ◽  
JINGYU ZHANG ◽  
YAFENG WU ◽  
CHUNCAI MENG

Bound rubber in carbon black (CB) filled rubber (natural rubber (NR) and styrene–butadiene rubber (SBS)) was prepared by the solvent method. The nanomorphology of CB and rubber/CB soluble rubber was observed by atomic force microscope. The results show that high-structure CB DZ13 has a "grape cluster" structure which consists of many original particles with the grain size of about 30–50 nm. Graphitizing process of CB decreases the amount of bound rubber. The NR/DZ13 soluble rubber with island–rim structure has been obtained, where the islands are DZ13 particles and the rims around the islands are occupied by NR film. But when the graphitized DZ13 particles were used as fillers of rubber, we have only observed that some graphitized DZ13 particles were deposited on the surface of the globular-like NR molecular chains, instead of the spreading of NR molecular chains along the surface of DZ13 particles, indicating that graphitized DZ13 has lower chemical activity than ungraphitized DZ13. Especially, we have already observed an interesting unusual bound rubber phenomenon, the blocked "bracelet" structure with the diameter of about 600 nm in which CB particles were blocked in ring-shaped SBS monomer.


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