On the resilient modulus and permanent deformation characteristics of stabilized recycled aggregates

Author(s):  
C Gnanendran
Author(s):  
Louay N. Mohammad ◽  
Chris Abadie ◽  
Rana Gokmen ◽  
Anand J. Puppala

Permanent deformation and moisture damage are common distresses found in pavements today. The use of mineral fillers such as hydrated lime is known to provide a decrease in moisture susceptibility. In many cases, mineral fillers will also increase the mixture stiffness. Conventional asphaltic concrete mixtures and mixtures modified with hydrated lime were evaluated for their fundamental engineering properties as defined by indirect tensile strength and strain, permanent deformation characteristics, resilient modulus, and fatigue resistance. A typical Louisiana low-volume dense-graded mixture was used. The test factorial included two aggregate types (limestone and gravel) and two asphalt cement types (a conventional AC-30 and one modified with styrene-butadiene polymer). The results indicated that the addition of hydrated lime as mineral filler improved the permanent deformation characteristics and fatigue endurance of the asphaltic concrete mixtures. This improvement was particularly apparent at higher testing temperatures with mixes containing polymer-modified asphalt and limestone aggregate.


2021 ◽  
Vol 13 (6) ◽  
pp. 3315
Author(s):  
Mansour Fakhri ◽  
Danial Arzjani ◽  
Pooyan Ayar ◽  
Maede Mottaghi ◽  
Nima Arzjani

The use of waste materials has been increasingly conceived as a sustainable alternative to conventional materials in the road construction industry, as concerns have arisen from the uncontrolled exploitation of natural resources in recent years. Re-refined acidic sludge (RAS) obtained from a waste material—acidic sludge—is an alternative source for bitumen. This study’s primary purpose is to evaluate the resistance of warm mix asphalt (WMA) mixtures containing RAS and a polymeric additive against moisture damage and rutting. The modified bitumen studied in this research is a mixture of virgin bitumen 60/70, RAS (10, 20, and 30%), and amorphous poly alpha olefin (APAO) polymer. To this end, Marshall test, moisture susceptibility tests (i.e., tensile strength ratio (TSR), residual Marshall, and Texas boiling water), resilient modulus, and rutting assessment tests (i.e., dynamic creep, Marshall quotient, and Kim) were carried out. The results showed superior values for modified mixtures compared to the control mix considering the Marshall test. Moreover, the probability of a reduction in mixes’ moisture damage was proved by moisture sensitivity tests. The results showed that modified mixtures could improve asphalt mixtures’ permanent deformation resistance and its resilience modulus. Asphalt mixtures containing 20% RAS (substitute for bitumen) showed a better performance in all the experiments among the samples tested.


2019 ◽  
Vol 81 (6) ◽  
Author(s):  
Norfazira Mohd Azahar ◽  
Norhidayah Abdul Hassan ◽  
Ramadhansyah Putra Jaya ◽  
Hasanan Md. Nor ◽  
Mohd Khairul Idham Mohd Satar ◽  
...  

The use of cup lump rubber as an additive in asphalt binder has recently become the main interest of the paving industry. The innovation helps to increase the natural rubber consumption and stabilize the rubber price. This study evaluates the mechanical performance of cup lump rubber modified asphalt (CMA) mixture in terms of resilient modulus, dynamic creep and indirect tensile strength under aging conditions. The CMA mixture was prepared using dense-graded Marshall-designed mix and the observed behavior was compared with that of conventional mixture. From the results, both mixtures passed the volumetric properties as accordance to Malaysian Public Work Department (PWD) specification. The addition of cup lump rubber provides better resistance against permanent deformation through the enhanced properties of resilient modulus and dynamic creep. Furthermore, the resilient modulus of CMA mixture performed better under aging conditions.  


2014 ◽  
Vol 26 (3) ◽  
pp. 512-519 ◽  
Author(s):  
M. A. Rahman ◽  
A. Arulrajah ◽  
J. Piratheepan ◽  
M. W. Bo ◽  
M. A. Imteaz

Author(s):  
Matthew W. Frost ◽  
J. Paul Edwards ◽  
Paul R. Fleming ◽  
Stuart J. Arnold

With the increasing agenda for sustainability, the United Kingdom is attempting to move away from the empirical design of pavement foundations to develop a performance specification approach that facilitates analytical design. The measurement of the subgrade performance parameters of resilient modulus and resistance to permanent deformation is required for analytical design. These parameters ideally should be assessed concurrently under loading and environmental conditions similar to those the materials will experience in the field. To date, measurement of these parameters is largely confined to research laboratories using cyclic triaxial testing with advanced on-sample strain measurement. This apparatus is considered too complicated for routine commercial use; hence, the implementation of laboratory performance evaluation for routine pavement foundation design is potentially limited. A previous program of cyclic triaxial testing on clay subgrades indicated a series of useful correlations between strength and permanent deformation behavior (via a threshold stress) and material resilient modulus at this threshold. The previous work is reviewed; with these correlations, data from tests performed on three different clay materials to develop simplified equipment and procedures for the routine measurement of the required design parameters are presented. Simple pseudostatic tests can measure a subgrade modulus for a simplified performance-based design. The previous data (in the light of the recent work) were reevaluated to show a boundary correlation that may allow a shear strength–based parameter to control (in design) the onset of permanent deformation, and the ways long-term subgrade water content changes can be accommodated are detailed.


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