Resilient Modulus Values Research Articles

Technical Investigation of the Usability for Foamed Bitumen Stabilized Materials inAsphalt Pavements

Asphalt recycling efforts are increasing in order to reduce the effects of high energy and rawmaterial consumption in the asphalt sector. One of the most common methods for using oldasphalt material, which still retains some value, is recycling with foam bitumen.In practice, for the preparation and evaluation of cold mixes produced using foam bitumen, ITS(Indirect Tensile Strength) and MR (Resilient Modulus) methods are generally used. Amongthese methods, ITS is mostly applied for the evaluation of the materials optimum percentagesvalues and MR test is also used for the evaluation of mixture performance.In the experimental study, firstly for the cold mixes prepared with foam bitumen, optimum foambitumen values of the production series were determined by ITS test. Then, reproductions weremade for these optimum values and resilient modulus values were determined. It was found thatthe ITS and MR values were significantly affected by the material gradation and this showedthe opposite tendency for the materials with the same gradation. The type of active filler waseffective the same as the values of the mixtures on ITS and MR. Especially, the MR resultswere affected by the bitumen grade. As a result of the study, evaluation limit values; 225 kPafor ITSDRY value, 150 kPa for ITSWET value and 70% for TSR, 400 MPa resilient modulus valueand 0.21 layer coefficient value are recommended for FBSM (Foam Bitumen StabilizedMaterial).

Long-Term Performance of Flexible Pavements Constructed on Recycled Base Layers

There has been an increased interest in using reclaimed asphalt pavement (RAP) aggregates as a base course in Wisconsin for the offered economic and environmental benefits. Laboratory studies showed that RAP can have resilient modulus values higher than typical natural aggregates, and can also have higher durability, especially in freeze–thaw cycles. However, it is also recognized that RAP exhibits temperature sensitivity and larger permanent deformations than natural aggregates. How these characteristics manifest themselves in the northern U.S. climates can only be assessed by long-term observation of field performance. Wisconsin Department of Transportation (WisDOT) has been using RAP as a base course for over 30 years. The qualitative assessment of WisDOT roads constructed with RAP showed they are performing adequately. However, this impression has not yet been verified quantitatively. This paper presents a quantitative assessment and comparisons for field performance of pavement test sections constructed with RAP and natural crushed aggregate (CA) base course layers in Wisconsin. The performance was evaluated using pavement distress surveys of roadways containing RAP and CA, falling weight deflectometer (FWD), dynamic cone penetrometer (DCP) tests, and analysis of WisDOT’s available data. Based on the field evaluation, the performance of the hot mix asphalt (HMA) pavements with RAP was found adequate and comparable to those with CA base course layers. A recommendation was given that WisDOT shall continue the practice of using RAP in base course layers of HMA pavements, given proper quality checks for materials, and proper quality control/quality assurance measures being applied during construction.

Utilization of Modified Red Mud Waste from the Bayer Process as Subgrade and Its Performance Assessment in a Large-Sale Application

The utilization of red mud waste discharged from the Bayer production process used for extracting alumina from bauxite presents a pressing demand in the aluminum industry. This study aims to adopt a chemical modifier to solidify the Bayer red mud for its application in highway subgrade. The mechanism and properties of the modified red mud using a modifier composed of cement, phosphogypsum and organic polymer, were analyzed and investigated. It was found that the optimal modifier dosage of the solidified modifier was 8%. The three-day unconfined compressive strength of the modified Bayer red mud could reach up to 3 MPa and its strength loss when immersed in water at 7 days and 28 days measured less than 20%. For its real application as subgrade, its road performance could be achieved with good bearing capacity, including a resilient modulus value greater than 90 MPa, a dynamic deformation modulus reaching up to 140 MPa and the Falling Weight Deflectometer (FWD) value measuring less than 100 (0.01 mm). Compared with traditional lime or cement stabilized soil, using locally modified Bayer red mud for subgrade filling can reduce the project cost, minimize the consumption of non-renewable resources and reduce the emission of environmental hazards, thus providing an engineering reference for large-scale and resource-based road applications.

The feasibility of recycled micro polyethylene terephthalate (PET) replacing natural sand in hot-mix asphalt

Microplastic pollution is contaminating the human food chain worldwide. At the same time, construction excessively exploits natural sand, requiring the incorporation of alternative materials to achieve sustainable development. From this scenario, the study evaluates the potential of recycled micro-PET replacing natural sand on hot-mix asphalt (HMA) mechanical behavior by weight and volume. The materials’ characterization occurred via XDR, XRF, TGA/DTG, FTIR, SEM, and AFM tests. The Superpave mix design, X-ray micro-tomography (μ-CT), indirect tensile strength (ITS), resilient modulus (RM), and moisture damage tests were performed in conventional and PET-incorporated mixtures, considering 2% (in wt.), 4% (in wt.), and 8% (in wt. and vol.) substitutions. The 8% PET replacing sand by volume showed no significant change in the mixture’s optimum asphalt content (OAC) due to the binder absorption equivalence between the materials’ surfaces. For the same binder content, the increase in PET content in weight decreased the binder film thickness and increased the volume of voids, visualized as non-permeable micropores in μ-CT. Although adding and incrementing PET reduced the mixtures’ ITS and RM values, its most significant contribution was enhancing the resistance to moisture damage, especially for regions where the pavement deterioration process is associated with an intensive rainfall regime, thus demonstrating this application’s practical feasibility in concrete asphalt paving.

Characterisation of road base materials treated by hybrid alkali-activated binders and cationic asphalt emulsions

ABSTRACT Using suitable chemically stabilized materials to solve the moisture-related damages on the road pavement is still essential. This study investigated the influence of cationic asphalt emulsion (CAE) on a hybrid alkali-activated binder (HAB) consisting of fly ash, hydrated lime, and solid sodium hydroxide for the chemically stabilized road base material. Adding CAE to HAB would introduce the water-repellent and elastic properties of HAB. Crushed rock (CR) treated with HAB binder prepared with two concentrations of CAE (HAB-CAEs) was characterized using a test series of compaction, unconfined compressive strength, resilient modulus, and water absorption. The compaction test results showed that CAE could decrease the optimum water content and air voids at the maximum dry density. Using CAE increased the strength of the HAB-CAE-treated CR, resulting in a sufficient compressive strength of the flexible pavement base. In addition, the HAB-CAE-treated CR had a proficient energy absorption under a static loading condition. The addition of CAE to the HAB-treated CR also provided resilient modulus and stiffness values higher than those of the conventional cement-treated base material with less water absorption. Therefore, HAB-CAE could be a viable option as a sustainable pavement base material.

Influence of Seed Layer Moduli on Backcalculation Procedure and on Overlay Design of Flexible Pavements

The seed moduli selected for backcalculation analysis of multilayer flexible pavement can have significant effects on the performance of backcalculation software and, sometimes, the final solutions of the overlay designs. Therefore, this paper aims to analyze the variability of the resilient moduli (MR) obtained by backcalculation programs, taking different seed moduli as input data. To this end, data obtained from non-destructive structural evaluation (falling weight deflectometer [FWD]) were used in three different regions of Brazil. Thereafter, the deflection basin values and the seed moduli were inputted into the two backcalculation methods: linear elastic and finite element. By varying the RM seed of one of the layers by 100%, the percentage differences in the backcalculated moduli were computed within the range of typical resilient modulus (MR) values for paving materials, and close to the upper and lower thresholds of the usual moduli in Brazil. Furthermore, with the data provided by backcalculation software and crack monitoring, these were inputted into the flexible pavement design software (MeDiNa) to also analyze the influence of the seed moduli variability on the pavement overlay design, through the cracked area percentage parameter. Therefore, it was found that the seed moduli have a high influence on the backcalculated moduli, with percentage differences of up to 68.30%, mainly for the base and subbase layers of pavement. Even with the differences obtained in the values of the backcalculated moduli, it was found that the seed moduli did not cause a significant impact on the overlay design in which the percentage difference between the cracking predicted for the surface layer was less than 2.5%.

Evaluating the Service Performance of Heavy Axle Load Ballasted Railway by Using Numerical Simulation Method

To evaluate the service performance of the track substructure of heavy axle load (HAL) railway transportation, an inverse analysis was performed to estimate the resilient modulus values of the track substructure, based on the deflection data obtained from light falling weight deflectometer testing. Subsequently, a three-dimensional finite element model was developed to simulate the effect of the train speeds (v) and axle loads (F) on the typical dynamic responses in the railway track system. The results convincingly indicated that increasing v or F can amplify the track vibration. Finally, a critical stress ratio method was adopted to evaluate the service performance based on the numerical results. A recommended range of v and F was determined to maintain the long-term stability of the HAL railway line. The findings can provide guidance for designing the track and maintenance plans to avoid track support failures and ensure track infrastructure resiliency.

Investigating the Effect of Gradation, Temperature and Loading Duration on the Resilient Modulus of Asphalt Concrete

This research was carried out to assess the effect of aggregate skeleton, temperature variation, and loading duration on the resilient modulus of asphalt concrete mixtures. Two different gradation methods, i.e., the conventional method of gradation and the Bailey method of gradation, were adopted to design the aggregate skeleton. The effect of these gradation methods, with temperature and loading duration, on the resilient modulus of asphalt concrete has not been previously investigated. The Modified Marshall Test was used to determine optimum binder content against 4% air voids, and then volumetric and strength parameters were calculated against optimum binder content. For performance tests, specimens were prepared at optimum binder content using a Superpave gyratory compactor. An indirect tensile strength test on both types of mixtures was conducted, and a 20% value of indirect tensile strength was kept for peak load, whereas 10% was kept for seating load for conducting resilient modulus tests. The tests were conducted at 100 and 300 ms duration loads under two different temperatures, i.e., 25 oC and 40 oC. The results declared that aggregate skeleton, temperature, and loading duration have a prominent effect on the resilient modulus of asphalt concrete mixtures. Bailey gradation mixtures disclosed higher resilient modulus values than conventional gradation mixtures. Higher values of resilient modulus were observed for both gradation mixtures at low temperatures and under small duration loads than at high temperatures and large duration loads. The results of the two-way factorial design also confirmed the above findings. Doi: 10.28991/CEJ-2022-08-02-07 Full Text: PDF

Analysis of the Resilient Modulus and California Bearing Ratio in mixtures containing slate waste and clayey soil

The use of slate waste can help to reduce the impacts caused to the environment due to the decrease of the appropriate disposal areas and the disordered consumption of raw material. This article presents an analysis of the Resilient Modulus (RM) and the California Bearing Ratio (CBR) of this waste in mixtures with clayey soil. To analyze variations in RM and CBR due to the increase in the slate waste content, tests were carried out on reference mixtures (REF) and mixtures containing slate waste (SLT). The tests were carried out for mixtures of granular material (gneiss for REF and slate waste for SLT) and clay soil, containing different levels of granular materials (50%, 60%, 70%, 80% and 90%) It was observed that the values of Resilient Modulus and California Bearing Ratio of the SLT mixtures increased 62.8% and 127.0% with the addition of the slate waste between the SLT 50/50 and SLT 90/10 mixtures, respectively. This behavior was similar to that presented by the REF mixtures, which increased 125.0% in RM and 60.1% in CBR for the same addition of granular material. The results obtained indicate that the mixtures containing slate waste presented RM and CBR similar to those of conventional materials (such as the REF mixtures) used in layers of sub-base and the base of pavements. Finally, it was concluded that the relationship between RM and CBR is non-linear for both mixtures (REF and SLT) in function of granular material addition.

Structural sensitivity of an asphalt pavement to asphalt binder content and mix design method

The goal of this study was to analyze the structural sensitivity of a flexible pavement, whose asphalt layers underwent variations in its mechanical properties due to the asphalt binder content and the mix design method Marshall and Superpave. A variation of ±0.5% within the optimum asphalt binder contents was used (service tolerance) considering possible permissible variations in the asphalt binder content during the asphalt mixture manufacturing process. The values of resilient modulus and indirect tensile strength (Brazilian test) of the resulting asphalt mixtures were applied to the reference pavement structure analyzed by the me-PADS software. The results show that the variations in the asphalt binder content and the asphalt mixtures design method influence the mechanical properties and corresponding structural responses of the pavement investigated: the asphalt layers designed by the Marshall method presented greater sensitivity to the variation in asphalt binder content, which may constitute a technical differential of asphalt mixtures designed by the Superpave method.

Microstructure analysis of porous asphalt incorporating kenaf fiber in the pavement

Hot mix asphalt (HMA) is the most of the popular pavement in Malaysia and most economical materials available. Besides that, this pavement type also very suitable with this country climate but HMA need frequency rehabilitation and maintenance due the damages caused by traffic load. In ways to minimize the damage and increase the services life of pavement, modification of asphalt binder is one of the approaches to improve pavement performance and services life. HMA can be modified with many types of fibre including natural fibre. This study utilises the usage of natural fibre as modifier of porous asphalt. The performance of modified porous asphalt is assessed by microstructure analysis. Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), Fourier Transform Infrared Spectrophotometer (FTIR), Powder X-ray Diffractometer (XRD), and Permanence Deformation Resistance are some of the laboratory results that have been used. The characteristics of PA modification with 0.3% kenaf fibre are demonstrated in this research. In the interior structure of PA, kenaf fiber diffuses effectively. C and Ca elements contributed the most in the experiment, as did the element and chemical content of PA modified with kenaf fiber. In comparison to the control specimen, changed PA has more persistent deformation and PA with 0.6% kenaf fiber had the greatest resilient modulus value. From the results, it displays that the addition of natural fibre is able to enhance the performance of porous asphalt. This study also promotes the sustainable building materials especially in pavement construction.

Characterization of physical & mechanical properties of asphalt concrete containing low- & high-density polyethylene waste as aggregates

Coarse aggregate is one of the main ingredients of asphalt concrete as it plays a vital role in the serviceability and durability of a flexible pavement. This study aimed at evaluating the effect of partially adding waste plastic aggregates in asphalt mix and studying its influence on different physical and mechanical properties. For this purpose, plastic waste was collected from landfill sites and classified into low density polyethylene (LDPE) and high-density polyethylene (HDPE), and, shredded into aggregates of desired size. Natural aggregates were replaced with these synthetic aggregates in different proportions such as 5%, 15% and 25%. Results showed that the incorporation of both types of plastic wastes reduced the density of asphalt mixture due to increase in air voids. The stability and flow values increased up to 15% partial replacement of natural aggregates with LDPE and HDPE. Similarly, LDPE-25 samples had lowest rut depth followed by HDPE-25. HDPE-15 sample showed the highest value of resilient modulus with a percentage increase of about 168.5% as compared to control sample. The dynamic modulus of asphalt also improved with plastic aggregates. However, the dynamic modulus values reduced with the increase in frequency for all study samples.

Modification of roadbed soil by crushed glass wastes

This study aims to use the crushed glass obtained from waste flasks to improve the properties of the weak roadbed soil. The study included crushing and powdering waste flasks. Afterward, the crushed glass was sieved and separated into three classes depending on the particle size: class A contains particles with diameter less than 4.75 mm and more than 1.18 mm, class B contains particles with diameter less than 1.18 mm and more than 0.08 mm, and class C contains particles with diameter less than 0.08 mm. For each of these classes, 6 different crushed glass contents were mixed with a weak roadbed soil to study their influences on its engineering properties. To attain this objective, four laboratory tests were applied: California Bearing Ratio (CBR), which determines the bearing value and the swelling ratio, triaxial compression test under cyclic loading, which determines the resilient modulus (MR), and the Oedometer test, which determines the compressibility coefficients (Cc and Cr). The results showed that increasing the crushed glass content enhances the tightness of the roadbed soil and reduces its volume changeability. Nevertheless, the use of class C showed the highest enhancement compared to the other two classes. Compared with original roadbed soil, CBR values and resilient modulus (MR) values of the roadbed soil samples mixed with 18% of class C of the crushed glass were increased to more than 8 times and 4 times respectively. In addition, swelling ratio, Cc, and Cr were reduced to 53%, 50%, and 35% respectively.

Performance of granular road base and sub-base layers containing recycled concrete aggregate in different ratios

ABSTRACT In this study, the usability and performance properties of recycled concrete aggregates (RCA) as granular road base (GRB) and granular road subbase (GRSB) material were investigated. A natural aggregate and the RCAs obtained from concretes with three different compressive strength and mixtures created by adding the RCAs to NA at the ratios of 25, 50 and 75% were used. Physical properties, modified Proctor, resilient modulus, permanent deformation, California bearing ratio (CBR), and permeability tests were carried out on all mixtures. Resilient modulus values (Mr) were obtained using three different resilient modulus models. The highest Mr value among pure RCAs was observed for RCA2 (average of 200 MPa). For the mixture samples, the highest Mr values were obtained in the mixtures containing RCA1 (average of 250 MPa). The minimum of permanent deformation value (ϵ p ) for the mixtures was obtained when the ratio of the RCA1 in the mixtures was 50% (ϵ p = 0.238%). The obtained CBR values were not related to the Mr values, and the highest CBR values were found for the pure RCAs (average of 126%). High permeability coefficient values (average of 9.973×10−6 m/s) were obtained for the RCAs. As a result, it was more appropriate to blend the RCAs with the natural material rather than to use them in pure form. In general, it was appropriate to use 50% of RCAs in the mixtures. It was observed that if concrete compressive strength is as high as in RCA1 (18.5 MPa), RCA can be used even in the mixture at a ratio of 75%.

Influence of tensile strength of geogrid and subgrade modulus on layer coefficients of granular bases

This paper presents a series of large-scale laboratory experiments conducted on pavement sections to evaluate the performance of geogrid-reinforced base layer overlying various subgrade conditions (resilient modulus ranging between 10 MPa and 72 MPa). Four types of geogrids with different tensile strengths, aperture sizes, and polymer types were used to investigate the influence of geogrids on the structural coefficients in terms of modulus improvement factor (MIF) and base layer coefficient ratios (LCRs). Further, a thorough analysis was performed on a three-layer flexible pavement system to propose firstly new models for base layer coefficients (a2u) for control (unreinforced) sections; and secondly, LCR equations and layer coefficient models for geogrid-reinforced base layers (a2r). The experimental results indicate that the stiffness of the subgrade significantly influences the performance of the pavement system. The optimum reinforcement depth was found to be one-third of the base layer thickness measured from the top surface. For an optimum geogrid configuration on a weak subgrade, a maximum LCR value obtained was about 1.8. As-built pavement section of Interstate Highway-8, Arizona, was evaluated to validate the proposed models. Based on the study, limiting values for MIF and LCR for geogrid-reinforced bases were proposed. Finally, a set of design charts were provided to determine the granular layer (base and subbase) thickness for a given subgrade and traffic conditions and a practical range of base layer resilient modulus values (200–400 MPa).

Predicting Resilient Modulus of Cementitiously Stabilized Subgrade Soils Using Neural Network, Support Vector Machine, and Gaussian Process Regression

Artificial neural network (ANN), support vector machine (SVM), and Gaussian process regression (GPR) were developed in this study for predicting resilient modulus (Mr) values of cementitously stabilized subgrade soils. A database was developed using laboratory test results on 160 specimens prepared by using four soils stabilized with three cementitious additives, namely, lime (3%, 6%, 9%), CFA (5%, 10%, 15%), and CKD (5%, 10%, 15%). Of these, 120 specimens (development dataset) prepared using three types of soils were used in development, and the remaining 40 specimens (validation dataset) were used in the validation of the developed models. A commercial software, MATLAB, was leveraged to develop three ANN models (radial basis function network/RBFN; a multilayer perceptrons network/MLPN with one hidden layer; and MLPN with two hidden layers); four SVM models (linear, quadratic, cubic, and radial basis function kernels); and three GPR models (rational quadratic, Matérn, and exponential kernels) by using codes written in MATLAB language. The strengths and weaknesses of the developed models were examined by comparing the predicted Mr values with the observed/experimental values with respect to the mean squared error (MSE) values and determination coefficient (R2) values. Through comprehensive comparison among these three types of models, an MLPN model with one hidden layer was determined as the best performing model developed in this study. It can be used to predict Mr of cementitiously stabilized subgrade soils for Level 2 pavement design applications. This model as well as the other models could be refined using an enriched database.

Stabilization of PET plastic-demolition waste blends using fly ash and slag-based geopolymers in light traffic road bases/subbases

Polyethylene terephthalate (PET) plastic and construction and demolition (C&D) wastes contribute to a substantial fraction of the annual landfilling waste composition of the world. Substituting traditional road construction materials with PET/C&D blends is a sustainable solution for the increasing landfilling requirement and increasing demand for the natural quarry aggregates. This study evaluates the main geotechnical parameters of the geopolymer-stabilized blends comprising of two main C&D types, namely recycled concrete aggregate (RCA) and crushed brick (CB), in blends with 5% PET fragments (% by mass). 10%Fly ash (FA), 10%Slag (S) and 5%FA + 5%S were used as the precursors at a fixed liquid activator to precursor ratio of 0.4, and the alkaline activator for the geopolymer solution was comprised of 30:70 ratio of liquid NaOH:Na2SiO3 solution. Strength and stiffness characteristics of the stabilized blends were evaluated by unconfined compressive strength (UCS) tests. The resilient modulus (MR) values of the geopolymer-stabilized blends under different cyclic axial stresses and confining stresses were assessed by repeated load triaxial (RLT) tests. Bulk stress and three-parameter model parameters were determined from the RLT test data to predict the variation of MR of the geopolymer-stabilized PET/C&D blends. All the geopolymer-stabilized blends using 5%FA + 5%S and 10%S as precursors satisfied the minimum UCS limit of the granular materials for light traffic road bases/subbases. Geopolymer-stabilized PET/C&D was identified as a potential, sustainable option for the stabilization of upcoming road bases/subbases.

Permanent Deformation and Rutting Resistance of Demolition Waste Triple Blends in Unbound Pavement Applications.

Virgin quarried materials are becoming increasingly scarce in our environment, and these materials are no longer a viable or economical solution for the construction industry. The construction industry is constantly seeking new markets for recycled waste in civil engineering applications. This research’s primary focus is the optimization of the usage of recycled materials such as recycled glass (RG), crushed brick (CB), and crushed concrete (CC), in pavement base/sub-base applications. Various percentages of RG, up to 40%, were blended with two types of CC in this research. The CC and CB, which were used as triple blends in this research, were utilized for the upper (100% CC) and lower sub-bases (up to 50% CB). This study sought to establish the maximum amount of RG that could be incorporated in the triple blends with CB and CC whilst maintaining an acceptable performance. Thus, a comprehensive series of fundamental and advanced geotechnical laboratory tests, including repeated load triaxial (RLT) and wheel-tracker (WT) tests, were performed to assess the engineering properties and permanent deformation characteristics of these triple blends. The particle-size distribution curve and California Bearing Ratio (CBR) values of all the blends met the minimum requirements. Results of RLT tests confirmed that all the nominated blends were found to provide the resilient modulus value required to be used as pavement materials. The WT results on the triple blend with 15% RG showed that the specimen performed exceptionally well during the test and comfortably met the requirements to be used in pavement applications. Based on the engineering properties and permanent deformation results, up to 15% RG can be suggested for incorporation as an accompanying material in unbound roadwork applications. Subject to the outcomes of future field testing, there might be potential to increase the percentage of RG added in the blends up to 30%.

Stress and Strain Characteristic of Stone Mastic Asphalt Incorporating Eggshell Powder

Stone mastic asphalt (SMA) is a type of gap graded asphalt mixture. Due to large difference between the gap of large and small size aggregate, this type of mixture suffers a few drawbacks such as low resistance towards permanent deformation. Thus, the usage of ecofriendly and sustainable additive is crucial in enhancing the performance of SMA. Thus, this study is utilizing various amount of eggshell powder as asphalt modifier. Among the tests involve to evaluate the stress-strain characteristic of modified SMA are Resilient Modulus Test and Dynamic Creep Test. From the test, it shows that the addition of 4% eggshell powder produces the highest value of resilient modulus and lowest value of dynamic creep for SMA. In conclusion, this study proves that the eggshell powder is capable in enhancing the performance of SMA especially in terms of permanent deformation resistance.

Performance of Stone Mastic Asphalt incorporating Kenaf fiber

Stone mastic asphalt (SMA) is a type of gap-graded asphalt mixture that contain large gap between big size and small size of aggregate. These criteria tend to reduce the tensile strength of mixture. To solve this, SMA usually mixed with synthetic fiber to increase tensile strength. However, synthetic fiber is costly and rarely obtained from local supplies. Thus, the aim of this study is to utilize different percentages of natural fiber which is kenaf fiber in SMA to overcome issues related to SMA. Among the test involved were LA Abrasion, Marshall Stability, Resilient Modulus, and Dynamic Creep. From the results, it shows that the addition of 0.2% fiber contributes to lowest value of abrasion. In addition, 0.2% fiber also produces the highest density of SMA20 (Stone Mastic Asphalt Grade 20). It could be seen that 0.6% of kenaf fiber producing highest value of resilient modulus. Dynamic creep also shows a significant value for 0.2% amount of kenaf fiber. Thus, it can be concluded that the existence of fiber is capable in enhancing the performance of SMA which is evident for instance, the density. The outcome of this study also contributes to the improvement of current guideline in designing SMA mixture especially for Public Work Department of Malaysia.