Comparison of Linear Viscoelastic Properties of Crumb Rubber–Modified Binders Measured Using Parallel-Plate and Concentric Cylinder Geometries with Asphalt Mixture Dynamic Modulus

2020 ◽  
Vol 32 (2) ◽  
pp. 04019352 ◽  
Author(s):  
Anas A. Jamrah ◽  
M. Emin Kutay
Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5051
Author(s):  
Fei Zhang ◽  
Lan Wang ◽  
Chao Li ◽  
Yongming Xing

To identify the most accurate approach for constructing of the dynamic modulus master curves for warm mix crumb rubber modified asphalt mixtures and assess the feasibility of predicting the phase angle master curves from the dynamic modulus ones. The SM (Sigmoidal model) and GSM (generalized sigmoidal model) were utilized to construct the dynamic modulus master curve, respectively. Subsequently, the master curve of phase angle could be predicted from the master curve of dynamic modulus in term of the K-K (Kramers–Kronig) relations. The results show that both SM and GSM can predict the dynamic modulus very well, except that the GSM shows a slightly higher correlation coefficient than SM. Therefore, it is recommended to construct the dynamic modulus master curve using GSM and obtain the corresponding phase angle master curve in term of the K-K relations. The Black space diagram and Wicket diagram were utilized to verify the predictions were consistent with the LVE (linear viscoelastic) theory. Then the master curve of storage modulus and loss modulus were also obtained. Finally, the creep compliance and relaxation modulus can be used to represent the creep and relaxation properties of warm-mix crumb rubber-modified asphalt mixtures.


2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Xinquan Xu ◽  
Guilin Lu ◽  
Jun Yang ◽  
Xinhai Liu

High-modulus asphalt concrete (HMAC) is considered as an effective paving material for addressing the increasing heavy traffic and rutting problems. Therefore, one high-modulus agent was used in this study to prepare high-modulus asphalt binder with different dosages. The objective of this study is to investigate the performance and modification mechanism of high-modulus asphalt. The effects of high-modulus agent on the viscoelastic properties of asphalt with different dosages were quantified via rheological tests as compared to base binder and styrene-butadiene-styrene- (SBS-) modified asphalt. Moreover, the modification mechanism of the high-modulus agent was examined using fluorescence microscopy and infrared spectrum test. Based on rutting and dynamic modulus tests, the differences of road performances between high-modulus modified asphalt mixture and SBS-modified asphalt mixture were compared. The results demonstrate that the high-modulus agent improves the high-temperature performance and viscoelastic properties of the matrix asphalt. When the dosage increases to 6.67%, the modification effect is better than that of the SBS-modified asphalt. Furthermore, the results of the rutting test show that the high-modulus modified asphalt mixture has better resistance to deformation than the SBS-modified asphalt mixture. The dynamic modulus test further demonstrates that the high-modulus modified asphalt mixture exhibits superior performance in high-temperature range. Fluorescence microscopy shows that the high-modulus agent particles can swell in the asphalt to form polymer links that improve the viscoelastic properties of the asphalt. Based on the results of the infrared spectrum test, it can be concluded that a high-modulus agent changes the asphalt matrix via physical blending modification.


2005 ◽  
Vol 19 (07n09) ◽  
pp. 1198-1204 ◽  
Author(s):  
W. H. LI ◽  
P. Q. ZHANG ◽  
X. L. GONG ◽  
P. B. KOSASIH

The paper presents investigation of dynamic properties of MR fluids by using a rheometer with parallel-plate geometry. The sample is reduced iron powder based MR suspensions. Linear viscoelastic properties of such sample, which can be variably controlled using a magnetic field, are obtained and summarized based on oscillatory tests. Four field-induced regimes, I, II, III, and IV, are found in the system, which are defined by three critical field strengths: BC1< BC2< BC3. MR fluids in regime I through IV experience four typical structural convolutions: coexisting of particles and random chains; coexisting of chains and random clusters; coexisting of clusters and chains; stable clusters. Such results are in good accord with experimental results achieved by Liu's group using light scattering techniques.


Author(s):  
Salih Kocak ◽  
M. Emin Kutay

Three major methods are used to produce crumb rubber modified asphalt pavement: the dry process (CRDry), the terminal blend process (CRTB), and the wet process (CRWet). Although the CRDry process replaces the portion of fine aggregate in the asphalt mixture with crumb rubber (CR) particles, the CRWet process incorporates CR particles into hot liquid asphalt before it is mixed with aggregates. CRTB is known as a special type of CRWet process in which the CR is blended with asphalt binder at the asphalt terminal. In general, the CRWet process can integrate 15% to 22% CR by weight of the binder. This amount ranges from 10% to 12% in the CRTB process as a result of the limitations associated with transportation and pumping. This study investigated the feasibility of increasing the CR content of CRTB modified asphalt mixtures. The addition to the mixture of about 0.5% CR (by weight of the mix) through the CRDry process doubled the amount of rubber to be found in a conventional CRTB mix. The relative performances of the CRTB and the CRTB+CRDry processes [i.e., crumb rubber hybrid (CRHY)] were investigated with respect to their linear viscoelastic properties, rutting susceptibility, moisture damage, resistance to fatigue, and low temperature cracking. It was shown that it was possible to increase the amount of CR in the mixture through the use of the CRHY method proposed here, without adverse effect on the performance of the mixture.


Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3446
Author(s):  
Wladyslaw Gardziejczyk ◽  
Andrzej Plewa ◽  
Raman Pakholak

The use of rubber granulate in the composition of asphalt mixtures, as well as the use of poroelastic layers, is indicated by many research centers as a factor with a positive effect on tire/road noise reduction. Attention is however paid to their lower structural durability compared to asphalt concrete (AC) or stone mastic asphalt (SMA). Stone mastic asphalt reducing tire/road noise (SMA LA) layers have also been recently used as low-noise road surfaces. The article presents the test results of viscoelastic properties of asphalt mixtures SMA8 LA, SMA8 LA containing 10%, 20%, and 30% of rubber granulate, with bitumen 50/70, bitumen 50/70 modified with styrene butadiene styrene (SBS) copolymer, crumb rubber, and mixtures with bitumen modified simultaneously with crumb rubber and SBS copolymer. The reference asphalt mixture was the porous asphalt (PA8). The presented results of water damage resistance, degradation resistance in the Cantabro abrasion loss test, stiffness modulus as a function of temperature and hysteresis loop proved that the amount of rubber granulate and the type of binder significantly affect the values of these parameters. Attention was paid to the possibility of using the results of uniaxial cyclic compression tests when determining the proportion of rubber granulate in SMA8 LA mixtures. Tests of hysteresis loops and stiffness modulus confirm much higher elasticity of SMA8 LA mixtures with rubber granulate as compared to mixtures without the addition of granulate.


2007 ◽  
Vol 17 (6) ◽  
pp. 62563-1-62563-8
Author(s):  
Chelsea A. Braybrook ◽  
Jennifer A. Lee ◽  
Philip J. Bates ◽  
Marianna Kontopoulou

Abstract A newly designed and constructed sliding plate rheometer is used to measure the high frequency (210 Hz) linear viscoelastic properties of two model polymers: polybutene (PB) and polydimethylsiloxane (PDMS). Using well-known rheological models, extrapolations of the viscoelastic measurements obtained on a rotational parallel plate rheometer to a frequency of 210 Hz are used to assess the performance of the high frequency sliding plate rheometer. Good agreement between the extrapolated and measured data demonstrates the ability of the sliding plate rheometer to measure the high frequency rheological properties of both Newtonian and shear-thinning materials.


Author(s):  
Yasmina Mahmoudi ◽  
Salvatore Mangiafico ◽  
Cédric Sauzéat ◽  
Hervé Di Benedetto ◽  
Simon Pouget ◽  
...  

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1321
Author(s):  
Sanqiang Yang ◽  
Shuang Sun ◽  
Lusheng Qin ◽  
Qian Li

The applications of rubber-modified asphalt and its mixtures have received widespread attention due to the environmental and economic benefits of such materials. However, studies on the structural performance of rubber-powder-modified asphalt pavement are only concentrated on a certain scale, leading to research on the structural performance of pavement mostly focusing on mechanical responses at a macro scale. Therefore, the present study adopts the concept of multi-scale research to analyze the viscoelasticity of high-dosage-modified asphalt and its mixtures at a microscopic scale from the perspective of meso-mechanical analysis. In this paper, to ensure the overall durability of a structure, the effective asphalt film thickness and coarse aggregate angularity index of the test material were measured first. The viscoelasticity of asphalt modified with rubber powder was then analyzed using a Brinell viscosity test, scanning electron microscopy (SEM), and a dynamic shear rheometer (DSR). We determined the optimal amount of rubber powder to be 30%. A universal testing machine was used to study the influence of different temperatures and loading frequencies on the viscoelastic properties of different asphalt mixtures. Research on the dynamic modulus found that the incorporation of rubber powder increases the elastic properties of the mixture such that the rubber-powder-modified asphalt mixture had a higher dynamic modulus. At the same time, the high-dosage-modified asphalt mixture was found to be closer to an elastomer under a low temperature and high frequency. At a high temperature and low frequency, the asphalt mixture changed into a viscoelastic body whose viscous properties were mainly affected by the asphalt binder. The addition of rubber powder changed the temperature sensitivity of the asphalt and then affected the viscoelastic properties of the asphalt mixture.


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