Dense Gradation Research Articles

Research on the factors affecting the compressive strength of rubber powder modified cement-stabilized crushed stone based on orthogonal experiments

Based on an orthogonal experimental design, this study introduces rubber powder particle size alongside rubber powder content, aggregate gradation, and cement content as factors. A total of 16 mix proportions were formulated. For each mixture, compaction tests and unconfined compressive strength (UCS) tests were conducted. Using Statistical Product and Service Solutions (SPSS) software, a multifactor variance analysis was performed to determine the influence levels of the four factors on maximum dry density and compressive strength. The optimal mix proportion was selected based on compressive strength. The results indicate that aggregate gradation and rubber powder content significantly affect the maximum dry density of the mixture, with aggregate gradation having the greatest impact. Rubber powder content has the most substantial effect on compressive strength, while rubber particle size has the least influence. The optimal formulation is 7% cement content, 30-mesh rubber powder, 0.5% rubber powder content, and a skeletal dense gradation close to the median.

Study on Low Temperature Cracking Resistance of Carbon Fiber Geogrid Reinforced Asphalt Pavement Surface Combined Body.

Currently, there are limitations in the research on the use of carbon fiber geogrids to prevent low-temperature cracking in asphalt pavements. This study aims to comparatively investigate the effects of carbon fiber-based geogrid type and dense-graded asphalt concrete mixture (AC) surface combined body (SCB) type on the low-temperature cracking resistance of reinforced asphalt pavement through low-temperature bending damage tests. Two geogrid types were prepared: a carbon fiber geogrid (CCF) and a glass/carbon fiber composite qualified geogrid (GCF). Two SCB types were studied: AC-13/AC-20 and AC-20/AC-25. The results show that the improvement in the flexural tensile strength of CCF is similar to that for GCF. Moreover, under reinforced conditions, the improvement in the low-temperature cracking resistance of AC-20/AC-25 is better than that for AC-13/AC-20 by 16.26-24.57%. Based on the analysis, the reasonable ratio range of the aperture sizes to the major particle sizes in the dense gradation can achieve a more effective interlocking effect. This can improve the low-temperature cracking resistance of carbon fiber-based geogrid-reinforced samples. Then, increasing the bending absorption energy is a key way of improving the low-temperature cracking resistance of carbon fiber-based geogrid reinforcements. Eventually, the fracture type of carbon fiber-based geogrid-reinforced samples is a mixed plastic-brittle fracture. These results can provide a reference for the road failure analysis of geogrid-reinforced asphalt pavement.

Performance Evaluation and Degradation Analysis of Suspended Dense Broken Stone Road Foundation Stabilized by Cement under Conditions of Freezing and Thawing

A suspended dense graded broken stone road foundation stabilized by cement is a commonly employed material in roadworks, which is vulnerable to harm caused by freezing and thawing processes. This investigation intends to evaluate the laboratory behavior and the characteristics of freezing and thawing process-induced deterioration in a broken stone road foundation stabilized by cement with suspended dense grading, employing mechanical examinations and acoustical methods. The rate of mass loss in the broken stone road foundation stabilized by cement progressively rises, and the rate of decline in the compressive strength could potentially intensify as freezing and thawing processes augment. The modulus of resilience diminishes as freezing and thawing processes progress, and ultrasonic wave velocity also decreases. The patterns of mass loss, compressive strength decline, resilience modulus reduction, and ultrasonic wave velocity alteration adhere to a parabolic fitting relationship with freeze–thaw cycles, with an R2 above 0.95. The curves depicting the relationship of mass, compressive strength, resilience modulus, and ultrasonic wave velocity exhibit a steeper trend significantly after 10–15 cycles, which can be ascribed to the emergence of microcracks and the progression of flaws within the material. The evolution of damage in the broken stone road foundation stabilized by cement is monitored to progress through three distinct stages based on acoustic emission: initial, stationary, and failure. As freezing and thawing processes accumulate to 20 cycles, the length of initial phase correspondingly rises to three times, the length of failure stage diminishes to about one fifth.

Freeze-Thaw Damage Characterization of Cement-Stabilized Crushed Stone Base with Skeleton Dense Gradation.

The skeleton dense graded cement-stabilized crushed stone base is a widely used material for road construction. However, this material is susceptible to freeze-thaw damage, which can lead to degradation and failure, for which there is still a lack of an in-depth understanding of the freeze-thaw damage characteristics. This study aims to assess the mechanical performance and the freeze-thaw damage characteristics of the cement-stabilized crushed stone base with skeleton dense gradation based on a mechanical test and acoustic technology in a laboratory. There is a gradually increasing trend in the mass loss rate of the base material with an increase in freeze-thaw cycles. The curve steepens significantly after 15 cycles, following a parabola-fitting pattern relationship. The compressive strength of the cement-stabilized crushed stone base also decreased with a parabola-fitting pattern, and the decrease rate may accelerate as the freeze-thaw cycles increase. The resilience modulus of the base material decreased with increasing freeze-thaw cycles, following a parabolic trend. This suggests that the material's resistance to freeze-thaw damage decreases with increasing cycles. The ultrasonic wave velocity decreased with increasing freeze-thaw cycles, exhibiting a parabolic trend. This decline can be attributed to microcracks and defects developing within the material, offering insights for monitoring and predicting its service life. The damage progression of the cement-stabilized crushed stone base was found to occur in three stages: initial, stationary, and failure. The duration of stage I increased with freeze-thaw cycles, while the duration of stage III decreased. The findings provide valuable insights into the mechanisms and processes of freeze-thaw damage in a cement-stabilized crushed stone base with skeleton dense gradation.

Modeling the Dynamic Properties of the Polyurethane Mixture with Dense Gradation Using the 2S2P1D Model

The polyurethane (PU) mixture is a zero-emission and high-performance engineering mixture that could replace traditional asphalt mixtures for pavement paving. This paper investigated the feasibility of using the 2S2P1D model to characterize the linear viscoelastic (LVE) properties of the PU mixture in comparison to the styrene–butadiene–styrene (SBS)-modified asphalt mixture with identical aggregate gradation and binder content. The PU mixture showed higher prediction precision for dynamic modulus and lower prediction precision for phase angle compared to the SBS-modified asphalt mixture. The seven constants of the 2S2P1D model for the PU mixture differed significantly from those of the SBS-modified asphalt mixture. The PU mixture exhibited higher elastic properties and lower creep properties, but the viscous properties represented by the index of η were different from the loss dynamic modulus, which reflected the mixture’s viscous properties. The index η cannot accurately characterize the viscous properties of the PU mixture. The 2S2P1D model exhibited a higher prediction accuracy than the Sigmoidal Christensen Anderson and Marasteanu (SCM) model and could accurately simulate the LVE properties of the PU- and SBS-modified asphalt mixtures. However, the 2S2P1D model should enhance the creep and dashpot elements to provide a more accurate characterization of the properties of the PU mixture.

Comparative performance of DG mixes and SMA mixes with waste crumb rubber as aggregate replacement

This research paper presents a comparative study on the performance of asphalt mixes containing waste crumb rubber as an aggregate replacement. Two different mixes namely Dense Graded (DG) and Stone Matrix Asphalt (SMA) with different ratios of waste crumb rubber WCR (0.5%, 1.0%, 1.5%, and 2.0% by weight of aggregate) were produced. The performance tests including, Marshall stability, Marshall Quotient (MQ), tensile strength, tensile strength ratio, and deformation strength in Kim test were carried out on DG and SMA asphalt mixtures. The analyses of test results show that the performance of DG-mixtures is better than SMA-mixtures in term of Marshall stability, and Marshall Quotient and lower indirect tensile strength, and Deformation Strength than SMA mixes. The moisture susceptibility and temperature susceptibility can be reduced by the inclusion of waste crumb rubber in the DG asphalt mixture. A waste crumb rubber content of 0–1.0% by weight of aggregate is recommended for the aggregate replacement of the performance of asphalt concrete mixtures similar to that investigated in this study.

Study on the Influence Factors of the Dynamic Property of the Polyurethane Mixture with Dense Gradation

Similar to the asphalt mixture, the polyurethane (PU) mixture’s performance and characteristics are dependent on many variables. In this study, six variables, including aggregate gradation (limestone and basalt), aggregate type, PU type, PU content, and curing condition, and several parameter analyzing methods were chosen to determine the effect of variables on the dynamic property, rheological property, and rutting resistance of the PU mixture. The limestone aggregate gradation exhibited a substantial effect on the dynamic property, rheological property, and rutting resistance of the PU mixture; the basalt aggregate gradation exhibited significant influence on the dynamic property and rutting resistance, but a moderate effect on the rheological property. The aggregate type could influence the rheological property and rutting resistance. The slow curing speed of the PU binder decreased the dynamic modulus and rutting resistance but did not influence the phase angle. The rise in PU binder content would only improve the PU mixture’s resistance to rutting. The curing condition and color additive had no impact on the PU mixture’s properties. The generalized logistic sigmoidal (GLS) and Christensen Anderson and Marasteanu model (CAM) models could precisely predict the dynamic modulus and phase angle respectively disregarding the PU mixture features. PUM-10/B exhibited the greatest rutting resistance. The findings will aid in comprehending the properties and influencing factors of the PU mixture as well as in designing the desired mixture.

Use of Waste Material as Filler in Bituminous Mix Design

Abstract: Bituminous concrete is a costlier and highest payment flexible payment layer. For satisfy the design requirements of stability and durability the bituminous mixes should be designed effectively. The ingredients of the mixture include dense grading of coarse aggregates, fine aggregates, fillers and bitumen binder. In this Study an attempt was made to find the effect of filler on the behavior of bituminous mixes. Fillers play an important role in the filling of voids and hence change the physical and chemical properties. Thus their effect is of utter importance. Bitumen in combination with filler forms mastic. This mastic can be seen as a constituent of mixture of asphalt that holds the aggregates together. An important role is played by the fillers that pass through 0.075mm sieve. With the increase in the amount of filler, Marshall Stability of the bitumen mix increases directly. Use of 4-8% filler in asphalt concrete is recommended by the Asphalt Institute. In India, waste concrete dust and brick dust are considered to be cheaper and are available in plenty. In this study an attempt was made to find the effect of fillers on the bitumen mixes. In this study, concrete dust and brick dust was used as filler. The properties of bituminous mixes containing these fillers were studied and compared with each other. For the purpose of comparison Marshall Method of mix design was used. In this study various tests were also conducted on aggregates and bitumen and the results were compared with the specifications. The study revealed that use of concrete dust and brick dust as filler improves the physical characteristics of bitumen. Marshall Stability and flow value of bitumen mix also improved.

Study on the Dynamic Performance of PU and SBS-Modified Asphalt Mixtures with Dense Gradation

A polyurethane (PU) mixture with excellent strength is regarded as an alternative to a modified asphalt mixture, but characteristic analysis on them is lacking. In this paper, the dynamic modulus of PU- and SBS-modified asphalt mixtures with the same gradation, aggregate type, and binder content was investigated and compared in terms of dynamic and viscoelastic properties. Compared with the SBS-modified asphalt mixture, the PU mixture with an extremely high dynamic modulus and reduced phase angle at high temperatures had lower temperature sensitivity, which allowed it to resist high-temperature deformation. While the phase angle did not show a statistically significant correlation, the dynamic modulus between the two mixtures did. The dynamic modulus and phase angle values of the PU mixture showed relatively small deviations and could be fitted to produce acceptable master curves, which exhibited obvious differences compared to those of the SBS-modified asphalt mixture. The PU mixture exhibited elastic properties during the test temperature range and, since its thermal rheological property is much smaller than that of the SBS-modified asphalt mixture, it is closer to viscoelastic material. This study provides an understanding of the PU mixture’s dynamic and viscoelastic properties, as well as material information for pavement design and performance prediction with PU mixture layers.

Laboratory Investigation into the Partial Replacement of Aggregates with Recycled High-Density Polyethylene in a Dense Graded Asphalt Mix

Plastic waste is a growing concern today, as landfills fill up and pollution leads to global climatic problems. Some research has been conducted on using plastics in asphalt, but the effect that high-density polyethylene (HDPE) can have in the performance of the asphalt is not understood. This research examines the impact on the moisture damage, rutting, and cracking resistance of recycled HDPE plastics as a portion of aggregates in a dense graded asphalt mix. Two types of recycled HDPE were used—flakes and pellets. Mixes with 5% by volume of recycled HDPE were designed and compared with a control mix. The results indicate that the use of recycled HDPE allowed for a reduction of 0.5% binder requirement. Tensile strength ratio testing showed that, with no anti-stripping agent, the HDPE-modified mixes had acceptable moisture resistance. Both types of HDPE-modified mixes showcased superior rutting resistance based on the flow number parameter. However, the use of HDPE decreased the cracking resistance of the mixes measured with the Illinois Flexibility Index Test at intermediate temperatures. The dynamic modulus test indicated a decrease in the stiffness of the mixes at low temperatures and confirmed the increase of the stiffness at high operating temperatures. Overall, the results indicate that the use of HDPE as partial replacement of aggregates is feasible and future research could explore balancing the performance of the HDPE-modified mix.

Study on the Phase Angle Master Curve of the Polyurethane Mixture with Dense Gradation

The phase angle master curve of the PU mixture is a new research field that is urgently needed to characterize the viscoelastic of the PU mixture under different conditions. In this paper, five master curve models, five shift factor equations, and four error minimization methods were introduced to fitting the phase angle master curve of the PU mixture. The results analysis indicated that the master curves fitted by different error minimization methods had small differences when the loading frequency was higher than 10−3 Hz. The R2 maximization as the main constraint and the others as the additional constraints were recommended as the error minimization method. The combination of the Christensen Anderson and Marasteanu model (CAM) and kaelble shift factor equation was recommended for fitting the phase angle master curve of the PU mixture. The phase angle master curve of the PU mixture did not follow the “Bell” shape of the asphalt mixture. The PU mixture with smaller temperature susceptibility would still be subject to the PU at higher temperatures and was closer to that of the viscoelastic material. The phase angle master curve construction was analyzed for the first time and proper master curve fitting parameters were recommended for pavement performance predicting and analyzing.

Study on the Construction of Dynamic Modulus Master Curve of Polyurethane Mixture with Dense Gradation

The PU mixture considered here is a new kind of pavement material with excellent road performance, which lacks study into its dynamic mechanical and viscoelastic properties. In this study, the dynamic modulus of the polyurethane (PU) mixture was fitted by using five master curve models, five shift factor equations, and four error minimization methods. According to test results, the log–log plot form was able to more effectively display the differences between master curves. The solver method, the sum of square error minimization (≤0.02), proved to be more appropriate and accurate with higher fitting parameter results. The line of equality statistic and Pearson linear correlation analysis results demonstrated that WLF and Kaelble equations were appropriate for five master curve models with trend line R2 values higher than 0.98. The GLS and SCM model with the WLF equation had the most accurate master curve fitting results. The dynamic modulus master curve shape of the PU mixture did not follow the traditional smooth “S” shape and did not show the ultimate dynamic modulus at extreme frequency. The viscoelasticity of the PU mixture is quite different from that of the asphalt mixture. This study recommended the most accurate error minimization method, the master curve model, and shift factor equations for characterizing the dynamic properties of the PU mixture.

Establishment and application of theoretical-empirical prediction model of VMA in hot mix asphalt mixture

Voids in mineral aggregate (VMA) is a basic gradation design index of mineral aggregate in hot mix asphalt (HMA). In order to avoid the tedious process of selecting qualified gradation by obtaining measured VMA values from a large number of experiments, a prediction method of VMA value ranking without testing is established in this paper. Several theoretical-empirical models about VMA corresponding to skeleton porosity, skeleton dense and suspension dense gradations are set up, respectively. According to VMA standard value, measured VCA and the established equation for calculating the passing rate of 2.36 mm or 4.75 mm sieve of skeleton dense gradation, the gradation types of several gradations to be analyzed can be determined, and then the corresponding prediction model maybe selected to predict the VMA value of each gradation. The experimental results based on AC13 (Asphalt concrete with nominal maximum particle size of 13.2 mm) show that the estimated VMA size order is exactly consistent with the measured values, which demonstrates the effectiveness of the prediction method.

Study on the Influence Factors of Dynamic Modulus and Phase Angle of Dense Gradation Polyurethane Mixture

Polyurethane (PU) mixture is a new pavement material with excellent pavement performance, and most research was focused on the enhancement of pavement performance, but rarely on the dynamic property. This paper studied the factors including gradation, aggregate type, PU type, and PU content, which may influence the dynamic property of the PU mixture. Test results showed that the PU mixture is a kind of linear viscoelastic material, its dynamic modulus and phase angle changed with test temperature and loading frequency, the dynamic modulus would drop by 40%~50% with the temperature raised from 5 °C to 55 °C. All of the factors could affect the dynamic property of the PU mixture which was proved by the analysis of covariance. The effect of gradation did not change with the increase of the nominal maximum aggregate size (NMAS), the dynamic modulus of the PU mixture with limestone was higher than that of the PU mixture with basalt, and the curing speed of PU could affect the ultimate stiffness of the PU mixture, and the increase of the PU content did not help in the increase of the dynamic modulus of the PU mixture. So, more consideration about the selection of gradation, aggregate type, PU type, and PU content should be taken into the design of the PU mixture, which could produce the best pavement structure combination and save more investment.

A Laboratory Study on Open and Dense Graded Cold Asphalt Emulsion Mixtures for Surface Courses

Cold Asphalt Emulsion Mixture (CAEM) is considered as an eco-friendly asphalt mixture because it eliminates the emission. It is produced at ambient temperatures and reducing the requirement to heat aggregates and bitumen prior to mixing process, so it is good for energy saving in pavement construction. In application, there are two type gradations of aggregate for cold asphalt mixture, dense gradation and open gradation. A series of laboratory works were conducted to analyse the performance of dense and open graded cold mixture for surface courses, which is the main objective of this study. Marshall Samples were kept indoor at room temperature for 7 days prior to Marshall Test to obtain the effect of curing process for cold mixtures. All samples were tested using Marshall Tests for stability and flow. The results show that dense graded mixtures need less bitumen content than open graded mixtures. For cured samples, dense graded mixtures produces higher Marshall Stability than open grades mixtures, while uncured samples have almost the same Marshall stability value for both gradations. For open graded mixtures, curing process reduce the porosity of mixtures.

Investigation on temperature shrinkage characteristics of the combined structure in asphalt pavement

The temperature shrinkage of materials primarily causes transverse cracking. Current research mainly focuses on the temperature shrinkage of single materials. This work aims to analyze the effect of the structural combination on temperature shrinkage. To this end, the temperature rise method was first discussed to measure the shrinkage coefficient to replace the traditional temperature drop method. Then, the temperature shrinkage coefficients of the lime–fly ash-stabilized macadam, and ATB and AC asphalt mixtures were measured. The effect of gradation types, lime–fly ash content, and nominal maximum aggregate size on the temperature shrinkage was studied. Finally, the temperature shrinkage of composite structural characteristics was analyzed. The results show that the difference between the temperature shrinkage coefficients obtained by temperature rise and drop methods was relatively small. Thus, the temperature rise method can be used to measure the temperature shrinkage coefficient. In addition, the lime–fly ash-stabilized macadam with the suspended dense gradation or a higher lime–fly ash content has the largest temperature shrinkage strain. The suspended dense gradation should be avoided, and the content of lime–fly ash should be approximately reduced to control the temperature shrinkage strain of the semi-rigid base course. As for the asphalt mixture, the temperature shrinkage strain increased with the decrease in the nominal maximum aggregate size. The asphalt mixture with a larger nominal maximum aggregate size should be given priority to control the temperature shrinkage. Finally, when combined with the base course or surface layer, the temperature shrinkage of the base course was promoted by the surface layer, while the base course inhibited the surface layer. Meanwhile, the mutual influence between the semi-rigid base course and the surface layer was more substantial than that of the mutual influence between the flexible base course and surface layer.

The optimal use of crumb rubber in hot-mix asphalt by dry process: A laboratory investigation using Marshall mix design

This paper aims to use the Marshall method to design and evaluate crumb-rubber modified (CRM) and conventional dense-graded (DG) hot mix asphalt (HMA), as there were limited previous experimental investigations that compared their properties by varying crumb rubber (CR) sizes, CR contents and aggregate types. Two types of crushed aggregate – diorite and granite – were mixed with 5.0% to 7.0% bitumen contents and 0%, 1%, 2% and 4% CR contents sized at 0.71 mm, 2 mm and 2.36 mm by dry process. The laboratory test results showed that the optimum bitumen content (OBC) and CR content that commonly satisfied international standards of CRM-DG-HMA by dry process and conventional DG-HMA were 5.5% and 1% respectively. CR content significantly contributed to the swelling of the CRM-DG-HMA, followed by the aggregate type and CR size. CRM-DG-HMA using granite aggregate was slightly more prone to swelling than that with diorite aggregate. Diorite-based CRM-DG-HMA with 2 mm CR size was more durable than conventional DG-HMA, granite-based CRM-DG-HMA and diorite-based CRM-DG-HMA with 0.71 mm CR size, with the last two being less durable than conventional DG-HMA. Granite-based CRM-DG-HMA was more stable and stiffer than conventional DG-HMA, while diorite-based CRM-DG-HMA was less stable but stiffer than conventional DG-HMA. Moreover, granite-based CRM-DG-HMA was more stable and stiffer than diorite-based CRM-DG-HMA with 0.71 mm CR size, with the latter being more stable and stiffer than diorite-based CRM-DG-HMA with 2 mm CR size. The findings from this paper have shown that partial replacement of mineral aggregate with CR in DG-HMA is a sustainable option, which could yield comparable or improved properties over conventional DG-HMA, provided that the CR size, CR content and aggregate type have been determined and selected in the mix design.

Influence of Compaction, Gradations, and Stress Levels on Fatigue Performance of SMA-13 Mixtures

The fatigue characteristics of the stone-mastic asphalt (SMA) mixture and pavement structure are the basis of SMA mixture pavement design. However, the fatigue performance of the SMA mixture compacted by a vertical vibration compaction method (VTM) has been rarely studied. This paper presents the indirect tensile fatigue test results of a laboratory investigation focused on the influence of compaction methods (Marshall compaction method, vertical vibration compaction method, and Superpave gyration compaction method), gradations (specification gradation and skeleton dense gradation), and stress levels on the fatigue performance of the SMA mixture with the nominal maximum particle size of 13.2 mm (SMA-13 mixture). Results showed that the fatigue life of the SMA-13 mixtures decreases linearly with the increase of the stress level under the same failure probability. The fatigue life of the SMA-13 mixture was 156% and 310% higher than that of the SGC and Marshall methods under the same loading stress, respectively. Furthermore, the fatigue life of the SMA-13 mixture with skeleton dense gradation was 55% higher than that of specification gradation. Through comparing the fatigue life of SMA-13 mixtures prepared under different compaction methods and gradations, the compaction methods of VTM and the skeleton dense gradation were recommended for SMA-13 mixture design.

Potential improvements in montmorillonite-nanoclay-modified Cold-Mix Asphalt

Over the years, Cold-Mix Asphalts (CMAs) used principally for pothole patching and partial-depth repairs in Ghana have performed abysmally. Given the convenience, environmental friendliness and low cost associated with CMA production, the use of the material in Ghana is likely to continue for a long time to come. Therefore, to justify it continual use in road maintenance, especially pothole patching, the material must be improved in quality considerably beyond what currently pertains to achieve a more successful product. Fillers used in bituminous mixtures have been identified as having the potential to improve mixture properties positively. In view of this, in the quest to improve CMAs, montmorillonite- nanoclay filler (pulverized clay particles of size 1-100 nm) was incorporated in CMAs formulated from five dense gradation regimes adopted from the Asphalt Institute M-19 Specification. The nanoclay filler was added from 1-3% by weight of aggregate at 1% incremental levels. Using the Marshall Mix Design procedure, mixture properties (Stability, Flow, Optimum Bitumen Content and Voids) were accordingly determined. It was observed that when montmorillonite nanoclay was introduced as a filler in the cold mixes, all the gradation groups recorded improvements in their stability at each nanoclay content. At 2% nanoclay content, all the mixtures yielded optimum values. The increase in stability can be attributed partly to the increase in adhesion between bitumen and aggregate and also partly to the possible increase in inter-particle friction occasioned by the presence of the nanoclay particles which add to the rigidity of the compacted matrix. However, on the contrary, flow values increased significantly. In between the nanoclay contents, from 1-2% and 2-3%, average flow increased by 1.8% and 12%, respectively. The same could be said of the Optimum Bitumen Content which increased for all gradation groups when nanoclay was added. The increase in Optimum Bitumen Content can be said to be accountable for the flow increases realized for mixtures with nanoclay. Even though high stability reflects the bitumen binding strength and the internal friction, a benchmark of the interlocking and friction resistance of aggregates, the high flow values observed are also indicative of the potential susceptibility of the cold mixes to rutting deformation, especially at elevated temperatures.

Laboratory Evaluation of the Properties of Dense Graded Asphalt Mixtures Containing Waste Glass Fibre and Crumb Rubber

Due to environmental issues and rising costs of construction materials, there is an increasing desire to use reclaimed asphalt pavement (RAP) material in road construction. However, using too much of this material may lead to impairment of fundamental properties of asphalt mix. Glass fibre material is a well-known modifier and could be used to compensate possible downgrade of properties. Research articles and theoretical material have shown that adding too much fibre glass reinforcement could cause damage to asphalt mixture. Therefore, in this research, reference mixture has been compared to three projected AC 11 surface mixtures with different amount of fibre glass. The same has been done to HMAC mixtures, but in this case, there is crumb rubber used as mixture modifier. Experimental part has shown that using fibre glass in asphalt mixtures for both construction layers may have positive influence on fundamental parameters of HMAC and AC asphalt mixes, which can be a good solvation for using waste glass fibre in road construction.