Juraidah Ahmad

Comparative evaluation of hot-mix asphalt design methods

This study was done to evaluate superior performing asphalt pavements (Superpave) mixture design using local materials in Malaysia. Comparison was also done with the conventional Marshall method-designed mixture conforming to the specifications of the Malaysia Public Works Department (PWD). The experimental plan consisted of a matrix involving one granite aggregate source, two different aggregate gradation and two different asphalt binder types. Local granite aggregates being produced presently were found to conform to the consensus and source aggregate properties criteria of the Superpave mixture design system. Mixture volumetric properties showed that Superpave-designed mixture uses less asphalt binder than the PWD Marshall mixture. Rutting and moisture susceptibility tests showed that Superpave-designed mixtures are more resistant to rutting and moisture damage compared with the PWD mixture. Mixture characterisation tests showed that Superpave mixtures have higher stiffness than the PWD mixture. These indicate that Superpave-designed mixtures are superior to the PWD Marshall-designed mixture.

Rutting Performance of Hot Mix Asphalt Mixture Using Nanopolyacrylate Polymer Modifier

Rutting is a common pavement failure in road pavement. Rutting occurs mainly due to several factors including increasing of vehicles numbers, environmental conditions and also due to construction and design errors. As a consequence the service life of asphalt pavement is affected and will be decreased. Various researches reported that using different types of polymers in bitumen modification could be a solution to delay deterioration of asphalt pavement. The main purpose of the study was to investigate the effect of the NPA polymer modifier on the rutting behaviour of the asphalt mixtures through Superpave designed mixtures. . Two different types of dense graded Superpave HMA mix were developed consists of Control mix and nanopolyacrylate (NPA) mix. Results showed that all the mixes passed the Superpave volumetric properties criteria which indicate that these mixtures were good with respect to durability and flexibility. Furthermore there is a significant difference between Control mix and NPA mix in terms of rutting in which rut depth after 8000 passes for Control mix was 5.94 mm while for NPA mix was 2.98 mm. The results of this investigation indicated that the Rutting test result of NPA demonstrates 3% better resistance to rutting than those prepared using Control mix. This is due to the addition of NPA to the bitumen has certainly improved the bitumen properties significantly and hence increase the resistant to rutting of the asphalt mixture. Therefore, it can be concluded that NPA polymer is feasible to be used as asphalt modifier and has potential for improvement in the field of pavement material and construction in future.

Privatization of low-volume-road maintenance management : Malaysian experience

In 2001, the Malaysian government privatized the maintenance of its federal road network. The network was divided into four maintenance regions. The southern region consists of about 4,000 km of roads; of that, about 1,800 km is under the Federal Land Development Authority (FELDA) scheme. Under the privatization contract, the concessionaire is required to carry out periodic, routine, and emergency maintenance of all roads within the FELDA scheme. The implementation of the privatized maintenance management program for the low-volume road network is discussed. The current management program includes road condition data collection, maintenance strategy and pavement materials selection, and use of innovative pavement maintenance technology. Data collection is carried out by using a high-speed road data collection survey vehicle; structural assessment is made by using the falling weight deflectometer, coring and dynamic cone penetrometer, and a conventional visual condition survey. An inventory system was also developed. Components of this privatized maintenance contract are discussed in detail.

Dynamic modulus of nanosilica modified porous asphalt

Porous asphalt (PA) is a flexible pavement layer with high interconnected air void contents and constructed using open-graded aggregates. Due to high temperature environment and increased traffic volume in Malaysia, PA may have deficiencies particularly in rutting and stiffness of the mix. A possible way to improve these deficiencies is to improve the asphalt binder used. Binder is normally modified using polymer materials to improve its properties. However, nanotechnology presently is being gradually used for asphalt modification. Nanosilica (NS), a byproduct of rice husk and palm oil fuel ash is used as additive in this study. The aim of this study is to enhance the rutting resistance and stiffness performance of PA using NS. This study focused on the performance of PA in terms of dynamic modulus with the addition of NS modified binder to produce better and more durable PA. From the result of Dynamic SPT Test, it shows that the addition of NS was capable in enhancing the stiffness and rutting resistance of PA. The addition of NS also increase the dynamic modulus value of PA by 50%.

Influence of Warm Porous Asphalt on Permeability Reduction Due to Binder Flow

Warm mix asphalt (WMA) is a new technology in Malaysian context. The technology can help to reduce the global warming issues. In this research, the warm mix asphalt technology was used in porous asphalt pavement which is known as warm porous asphalt (WPA) mix. WPA loses permeability mainly due to clogging. Apart from typical clogging agents such as dust and tyre rubber, the binder flow is also another source of permeability reduction. The objective of this study was to investigate the binder flow phenomenon that affected the permeability reduction in WPA. To obtain the binder flow phenomenon, samples were conditioned at 35 °C for 120 days. The different mixing and compaction temperatures with bitumen 60/70 + 3 % RH-WMA additive were used in preparing the samples. A falling head water permeameter was used to determine the permeability loss which is related to time and temperatures. The result from the permeability loss was significant to high mixing temperatures over time. Due to time, self-weight of the binder and high mixing temperature, the asphalt mastic start to flow down according to gravitational forces and finally the coefficient of permeability reduced, yet the time of flow increased. The outcome of this research indicated that the different temperatures during mixing and compaction were significant to the binder flow. Hence, the low mixing temperature using WMA technologies could reduce the clogging problem due to self-weight of the binder.

Moisture-Induced Damage Evaluation of Nanopolymer-Modified Binder in Stone Mastic Asphalt (SMA) Mixtures

This paper presents laboratory investigation on mix design and moisture-induced damage performance of nanopolymer-modified asphalt binder SMA mixture. The effect of nanopolyacrylate (NP) in the mixture was investigated using Marshall mix design and modified Lottman test. Nanopolyacrylate polymer-modified binder was prepared with addition of 0–6 % NP polymer by weight into asphalt binder. Results of SMA14 mixture showed that all the volumetric properties of the mixtures passed the Marshall requirement, which indicates that these mixtures were good with respect to durability and flexibility. The ITS of NC2% and NC4% mixtures increased with an increase in percentage of NP but not as good as the conventional mixture, NC0% which is added with PG76 polymer-modified binder. However, NC6% mixture showed higher tensile strength compared to PG76 modified binder. Results of the moisture-induced damage showed that all the mixes passed the AASHTOT283 criteria with TSR values greater than 80 %. The results also showed that the optimum NP obtained is 6 % by weight of asphalt binder is the most effective and potential proportion to improve moisture-induced damage performance. Thus, addition of nanopolyacrylate polymer to the binder has significantly improved the cohesion as well as adhesion properties of the binder, and hence the performance of stripping.

Abrasion Loss and Binder Draindown of Porous Asphalt with Nanosilica-Modified Binder

This paper details the performance evaluation of porous asphalt (PA) with nanosilica (NS)-modified binder in terms of binder draindown and abrasion loss. Both tests are widely used to evaluate the lower limit and upper limit of the design binder content for porous asphalt. The existence of nanoparticle with different proportions can affect binder draindown and abrasion resistance behavior of PA. Six different percentages of nanosilica were mixed with PEN 60–70 type of binder in this study. Then, all these blended modified binders were used to prepare PA samples using Marshall mix design method. Nanoparticle used in this study was nanosilica with the average size of 10–15 nm. Binder Draindown test was performed using a metal basket with 3 mm perforation. Then, abrasion loss value was evaluated using Los Angeles Abrasion Machine without steel ball. In accordance to PWD of Malaysia Specification for Road Works, which states that binder draindown for PA should not be more than 0.3 % of total weight of sample, while abrasion loss should not be more than 15 % also by weight of total sample. Based on Cantabro loss Test and Binder draindown test, 2–5 % NS are considered as the effective amounts of NS to be mixed with binder in order to reduce the abrasion loss and binder draindown of PA. In addition, 4 % NS is also considered as the optimum NS proportion. The existence of NS is capable to enhance the physical and rheological properties of asphalt binder, while at the same time it disperses well in asphalt binder. Thus, the performance of PA is also enhanced with the addition of NS in the binder.

Stripping Performance and Volumetric Properties Evaluation of Hot Mix Asphalt (HMA) Mix Design Using Natural Rubber Latex Polymer Modified Binder (NRMB)

Striping one of the most common pavement failure usually occurs in pavement structures. This failure reduced the service life of the pavement, reduced driver safety and increase cost of maintenance. Polymer modified binder has been conducted previously to find an alternative material in pavement construction that can be used as new improvement for asphalt mix design. This paper presents the stripping potential benefits of natural rubber (NR) for the asphalt mixtures used on pavement. This research evaluates the physical properties and stripping performance of dense graded Superpave-designed HMA mix. Two different types of dense graded Superpave HMA mix were developed consists of unmodified binder asphalt mix (UMB) and natural rubber polymer modified binder asphalt mix (NRMB). Natural rubber polymer modified binder was prepared from addition of 8 % of NR into asphalt binder. Stripping results from Modified Lottman test and Boiling Water test were determined to evaluate the performance of these mixtures. Results showed that all the mixes passed the Superpave volumetric properties criteria which indicate that these mixtures were good with respect to durability and flexibility. The Stripping result of NPMB demonstrates better resistance to stripping than those prepared using UMB mix. Addition of NR to the binder has certainly improved the binder properties significantly and hence increase the resistant to stripping of the asphalt mixture. The results also shows that the optimum NR obtained is 8 % by weight of asphalt binder is the most effective proportion that having potential to improve physical properties and the performance of polymer modified asphalt binder. Therefore, it can be concluded that the NR polymer is suitable to be used as a modifier to modified binder in order to enhance the properties of the binder and thus improves the performance of asphalt mixes.

Using Nanopolyacrylate and Nanocomposite as Binder Modifiers for Stone Mastic Asphalt (SMA)

This paper presents the potential benefits of using nanopolyacrylate (NP) and nanocomposite (NC) polymers as modified binders in SMA mixtures. The optimum binder content of the SMA control mix was designed using PG76 binder and Modified Lottman test (AASHTO T283) was used to determine the stripping performance. A total of six (6) SMA modified mix were prepared using NP and NC modified binder formulations at 2%, 4% and 6%. Results from tensile strength test showed that SMA-NC6 have the highest IDT (521kPa) followed by SMA-NP6 (511 kPa), SMA-Control (500 kPa), SMA-NC4 (449kPa), SMA-NC2 (403kPa) and SMA-NP2 (379kPa). The stripping test on both control and modified SMA mixtures showed that TSR values for all the mix pass the 80 percent limit which fulfils the AASTHO T283 standard requirement and are therefore least susceptible to stripping. Based on the tensile strength test results and stripping performance, it was found that the addition of NC and NP modified binder demonstrate great potential in SMA mixtures showing significantly improved cohesion as well as adhesion properties of the binder. The results from this study found that all the SMA mix are resistance to moisture damage which could sustain the load from vehicles and exposed to severe condition without large degradation of the structure.

Physical Properties of Modified Asphalt Binder with Nanopolyacrylate

Modification of asphalt binder using polymers has been increasingly used by our government to enhance the properties of bituminous mixes and to prolong the lifetime of roads in the face of increased traffic. This paper reports the procedure for determining the physical properties of asphalt binder using penetration grade binder of 80/100 with nanopolyacrylates (NPA). The asphalt binder was modified with different percentages of NPA (0, 2, 4, 6, 8 and 10 % by weight of asphalt binder) in order to determine the appropriate proportion of asphalt binder and NPA that can provide special potential in enhancing the properties and strength of the bituminous road to achieve the specifications required. Asphalt binder properties were evaluated in penetration, softening and penetration index. The results of this investigation indicated that the 6 % by weight of NPA in asphalt binder is the most effective proportion, having potential to improve physical properties of asphalt such as increasing softening point and decreasing the penetration and high penetration index. The results also demonstrate that the NPA binders outperformed conventional asphalt binder in term of engineering properties and it can be concluded that NPA polymer is feasible to be used as asphalt modifier and has potential for improvement in the field of pavement material and construction in future.