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The effects of modifying a 60/70 penetration grade bitumen with 3 wt% polyurethane (PU) and a Warm Mix Asphalt (WMA) additive, namely Rediset, were explored in this research. Penetration, softening point, viscosity, and ductility tests were employed for consistency testing, while the differential scanning calorimetry was used for thermal characterization. The topography and surface roughness of the modified bitumen were evaluated using atomic force microscopy. Adding PU and Rediset to the base bitumen (BB) stiffens the BB slightly, giving it a lower penetration and higher viscosity values, which improves the rutting resistance. The thermal transition of the glass temperature and melting temperature are similar to the BB. Furthermore, the addition of PU and Rediset to BB shows a clear bee structure topography in dry condition, indicating better dispersion, while in wet condition, the bee structure is mostly affected in the catana and para phase that reveals a reduced in the the wax content of the BB. The bitumen modified with PU and Rediset has a lower surface roughness than BB, making it less susceptible to moisture damage.

At present, there is a high demand for concretes with varying properties. Generally, concrete with high durability can be produced by considering the constituents of the concrete, such as cement, sand, aggregates, and water. The quality of concrete is also dependent on the mix design and production method, such as transporting and pouring of concrete. In recent years, the developed countries have been focusing on the issue of sustainability in construction to create a healthier environment and reduce the environmental impact of a building throughout its lifetime while optimizing its economic viability and ensuring the comfort and safety of the occupants. One way to achieve sustainability is using agricultural waste material such as palm oil fuel ash, rice husk, fly ash slag, sludge, and coconut shell in concrete production. This study performs a series of tests to investigate the effect of using alum sludge (AS) and palm kernel ash (PKA) with coconut shells as a partial replacement of aggregates. The concrete samples were subjected to compressive strength, flexural strength, rebound hammer, ultrasonic pulse velocity, water permeability, water absorption, carbonation, alkali-silica reaction, SEM, and shrinkage tests.

Pavement failures such as fatigue, rutting, cracking, bleeding, and stripping are typical pavement deterioration. Researchers have been experimenting with pavement modification to overcome these problems. This study determines the optimum binder content (OBC) for modifying an asphalt mixture with a partial replacement of coarse aggregate (5mm-14mm sieve size) with palm kernel shell (PKS). A 60/70 penetration grade bitumen was mixed with 10, 20 and 30% PKS at selected aggregate gradation following the Public Work Department of Malaysia (JKR/SPJ/2008-S4) specification. The preparation of 60 samples of unmodified and modified asphalt mixture employed the Marshall Method compacted with 75 blows. The OBC was determined based on five volumetric properties of asphalt mixture namely stability, flow, bulk density, void filled with asphalt, and void in total mix. The OBC and volumetric properties of the modified PKS asphalt mixture samples were compared with unmodified asphalt mixture samples in accordance to the specification. Results showed that the OBC sample with 30% aggregate replacement produced the highest OBC value of 5.53% relative to the control sample with 5.40% OBC. The trend for OBC with PKS replacement begins with 10% PKS with 5.30% OBC, 20% PKS with 5.32% OBC and 30% PKS. All volumetric properties of the PKS samples are within the specification limit. Thus, PKS has a promising potential as a coarse aggregate replacement in asphalt mixture.

This study seeks to examine the physical and high-temperature rheological performance of crude palm oil (CPO)/tire pyrolysis oil (TPO) composite asphalt to develop a more sustainable bio-rubberized asphalt (BRA) binder. The study uses the penetration, softening point, and dynamic viscosity tests to evaluate binder consistency and dynamic shear rheometer (DSR) tests to determine the linear viscoelastic properties before and after short-term aging. The nonlinear viscoelastic properties of modified asphalt were determined using the multiple stress creep recovery (MSCR) test. Results showed that the substitution of 20 asphalt with tire pyrolysis oil-modified bio-asphalt retained or enhanced the asphalt grade performance at high temperatures. All BRA binders have a higher aging resistance than the base asphalt. The MSCR results showed that, relative to all tested binders, the BRA binder containing 5 CPO and 5 TPO has optimal non-recoverable creep compliance (Jnr) and percentage of recovery (R) with a performance close to PG64H compared to the PG64S performance grade of the base asphalt. Overall, the findings of this study indicate that the incorporation of CPO/TPO in asphalt is suitable for producing bio-rubberized asphalt containing 20 recycled waste rubber and bio-oil and improves the high-temperature properties of asphalt to a certain extent. © 2021 Informa UK Limited, trading as Taylor & Francis Group.

The aim of the current study was to examine passengers’ perceived satisfaction with a monorail system by determining the factors that dominated their perception. For this study, 417 data points were collected through face-to-face questionnaire surveys in Kuala Lumpur, Malaysia, from 20 September 2019 to 10 December 2019. The study involved the use of several assessments to ascertain how the perceived satisfaction of passengers with the monorail service was influenced. The tests predicted which service factors fuelled this satisfaction and included an exploratory factor analysis, Spearman’s correlation test and an artificial neural network (ANN) model (termed the multilayer perceptron neural networks model) with a feed-forward backpropagation algorithm. The findings that were produced by these methods of analysing factors revealed the extraction of eight service-quality features as the key influences on the perceived satisfaction of passengers. The correlation test results revealed that these factors have a significant and positive relationship with perceived satisfaction. Finally, the ANN model with the optimum neuron number in the hidden layer is seven neurons. This model found that the dominant service quality factors that contributed to influencing passengers’ perceived satisfaction levels were (i) the provision of information, (ii) facilities, (iii) signage. The results of this study will benefit service providers, policymakers and planners in formulating effective strategies to enhance passengers’ satisfaction with the monorail service and increase the ridership.

This research was conducted to investigate the suitability of using two models; namely the artificial neural network (ANN) and adaptive system network model Neuro-Fuzzy (ANFIS) methods to predict the flexible pavement layer moduli. The falling weight deflectometer (FWD) data obtained from the Butterworth–Kulim Expressway (BKE) in year 2011 were used to test the models. The ANN and ANFIS models have been trained and tested continuously using different parameters until the optimum output is obtained. Thereafter, a validation process has been carried out to test the ability of whole models by calculating the coefficient of determination (R2), the mean absolute error (MAE), the mean squared error (MSE) and root mean squared error (RMSE). A total of 270 data sets have been used to develop the models. Based on the analysis conducted, it was found that both models are able to predict well the flexible pavement layer moduli(R2 > 0.90). However, a further comparison suggested that the ANFIS model yield a higher precision compared to the ANN model, with lower MAE, MSE and RMSE values. Therefore, it can be inferred that the neural network models have an excellent potential to replace the existing analytical and empirical models in predicting the flexible pavement layer moduli.

The high demand for bituminous binder has affected the price and quality of binders, and this has prompted research to be conducted to discover new binders from renewable resources. Thus, this study aims to characterize engineering properties namely the physical, thermal and chemical bonds of palm kernel oil polyol (PKO-p) bio-binder by means of consistency, rational viscosity (RV), differential scanning calorimetric (DSC), thermo-gravimetric analysis (TGA) and Fourier transform infrared spectrometer (FTIR) tests. A new bio-binder containing PKO-p was used as a partial replacement for petroleum-based binder. The PKO-p was produced through esterification then condensation processes. The proposed PKO-p was blended with a 80/100 penetration grade bitumen (BB) to produce the three different bio-binder (BIB), namely 100/0, 80/20, 60/40, and 40/60 bio-binder (weight of BB to BIB). Result showed that the values of the rotational viscosity (RV) of the BIBs were very consistent with that of the control binder, and that the compaction and mixing temperatures of the BIBs were reduced by 10% comparing with those for the control binder. Conventional testing of softening point and mixing temperature yielded similar results. The activation energy (Ea) for the three bio-binders were 85.47, 90.19 and 86.62 kJ/mol while that for BB was 71.44 kJ/mol. The thermal susceptibility of the BIBs blends were very similar with that of the BB and a small difference in weight losses was observed, i.e. with values from 0, 0.12%, 1.40% and 3.36% for BB, BIB1, BIB2 and BIB3 respectively. FTIR results showed that bio-binder was distinctly different from petroleum bitumen with regard to functional group, but very similar in other aspects. The findings of this study showed that the new PKO-p bio-binder has promising properties that made it a suitable alternative for petroleum-based binder used for road pavements construction.

Previous studies on coconut fibre reinforced concrete, and coconut shell concrete showed the potential of these wastes to be used as alternative materials in building construction. Presence of coconut fibre and coconut shell gives beneficial to concrete in increasing concrete toughness and produced lightweight concrete. In this experimental study, a combination of these coconut components (fibre and shell) was used as concrete composite to investigate its physical properties and compressive strength. Three types of concrete were cast, i.e. normal concrete, coconut shell concrete and coconut fibre reinforced coconut shell concrete. The amount of coconut fibre added in coconut shell concrete was 0.5% of mass volume. The results showed that replacing aggregate with coconut shell reduced the concrete density and compressive strength. Additional coconut fibre aided in holding the coconut shell concrete material and improve the slump value.

Aging of asphalt binders occurs when oxidation takes place in the binder, and this in turn causes the deterioration of pavement. This paper presents the effect of aging on 60/70 penetration grade asphalt binder incorporated with polyurethane (PU) in terms of chemical interaction, morphological and wettability properties. The chemical characteristics of the base binder (BB) and polyurethane modified binder (PUMB) was evaluated using Fourier Transform Infrared while the morphological properties were analyzed using Raman Spectroscopy. Contact angle test was performed to determine the wettability of PUMB over the aggregates. In this study, the BB is modified with 3 wt% PU. Rolling Thin Film Oven and Pressure Aging Vessel tests were conducted to simulate the short-term aged and long-term aged of the samples. Results showed that the addition of PU to BB has no significant effect on the chemical interaction in the modified binder before and after aging. The incorporation of PU and the aging of modified binder resulted in a reduced bee-structure in the BB, which in turn reduced the wettability of the asphalt binder. The incorporation of PU to the BB improved the oxidative aging of the binder.

Pavement failure phenomena is normally caused by low quality of mixture materials, especially bitumen. The modification of bitumen is one of the alternatives to improve the performance of the material. Therefore, this study was conducted to investigate the performance of a polymer-modified binder (PG-76) with the addition of different percentages of Reduce Heat-Warm Mix Asphalt (RH-WMA) at 1, 2, 3, 4 and 5 % (by-weight of binder). Several testings such as penetration, softening point and ductility tests were conducted to determine the physical properties of PG-76 and RH-WMA modified binders. The molecular structures of the materials were analysed using Fourier transform infrared spectroscopy (FTIR) test while the contact angle test was conducted to investigate the type of binder’s surface. In addition, an optical microscopy test was carried out to determine the morphological properties of the modified binders. Results show that the PG-76’s hardness decreases with the increasing of RH-WMA percentage, but the ductility values are still within the specification. The FTIR test shows an increase of RH-WMA percentage does not provide a significant reaction of the binder and the original properties of the materials remain. The morphology test shows that all percentage of RH-WMA selected are well dispersed in bitumen PG-76. Based on the contact angle results, all the PG-76 and RH-WMA modified binders fall into hydrophobic category.

This study aims to investigate the engineering properties (i.e., physical, chemical, and adhesion properties) of bitumen incorporated with RH-Warm Mix Asphalt (RH-WMA) additive. Base bitumen with a penetration grade of 80/100 was added with 3.0, 3.5, and 4.0% RH-WMA (by total weight of bitumen). The Response Surface Method (RSM) was used to determine the optimum values of the base bitumen and RH-WMA additive which meet the bitumen specification with penetration and softening point chosen as responses in the design layout. Three solutions of 3.04, 3.55 and 3.91% RH-WMA additive that were obtained from the RSM analysis were selected as the optimal values. Results of the physical tests show that adding RH-WMA increases the penetration and ductility values whilst simultaneously reducing the value for the softening point. Analysis of viscosity at various temperatures shows that RH-WMA additive lowers viscosity when the temperature was raised from 100 to 165 °C. The lower viscosity of the modified binders improves their workability. The result of the Fourier Transform Infrared (FTIR) test shows that there is no complex chemical reaction between the base bitumen and the RH-WMA. The surface free energy (SFE) test conducted on the base bitumen and the RH-WMA modified bitumen shows that the total SFE component of the base bitumen increases when higher amounts of RH-WMA was incorporated. The addition of 3.5% RH-WMA results in the highest SFE value of 24.98 mJ/m2. The increase in the total SFE suggests good adhesion between the bitumen and the aggregates.

Hot Mix Asphalt (HMA) is a combination of asphalt and aggregates that will give durable road surface for pavement and is widely used in Malaysia. However, due to damages caused by excessive traffic loadings, the HMA pavement normally required frequently maintenance and rehabilitation works. Therefore in recent years, research on modification of HMA has tremendously increased in highway construction field using natural sources and recycling products such as rubber, plastic, anti-stripping agents, waste materials and etc. This study was conducted to evaluate the effect of sugarcane bagasse ash (SCBA) used as filler in HMA. Experimental laboratory were done to compare the properties of normal HMA sample with modified HMA sample using SCBA. Result obtained for both sample were compared to Malaysian Public Works Department (MPWD) specification. The laboratory result reveals that SCBA are effective in increasing the Marshall stability, flow and Resilient Modulus of normal HMA. The SCBA increases Marshall stability by 0.6%, flow 4.9% and Resilient Modulus 17.4% respectively of ordinary HMA and all test and analysis parameters for asphaltic concrete of SCBA sample comply with MPWD requirements. Therefore, SCBA has potential in modifying normal HMA.

This paper discusses the utilization of Response Surface Method (RSM) statistical tool to determine the optimal amount of polyurethane (PU) for modifying 80/100 penetration grade bitumen. Central composite design (CCD) was used to develop an experimental design matrix where bitumen and PU are designated as the factors while penetration, softening point and viscosity are designated as the response. Numerical analysis of polyurethane modified bitumen (PUMB) shows that the optimal amount of PU in the modification of the bitumen is 5%. Verification of the chosen model shows that it is in consistent with the experimental value since the percentage error is less than 5%. Result of the consistency test shows that the addition of 5% PU resulted in higher penetration and viscosity values but lower softening point value, which in consequent improve bonding strength as the flow of bitumen is reduced.

Bridge parapet is one the most critical part of the bridge superstructure, which functions as a safety feature during accident or collision at the edges of the bridge. For steel parapet railing, complete full-scale field testing needs to be carried out before installation of new parapet railing. Field testing not only expensive but also very time-consuming for preparation and testing works. In this study, a comparison between the results of an actual field test and numerical simulation works was investigated. The chosen 3S two-beam steel parapet had passed the field testing conducted by the Korean Transportation Safety Agency (KOTSA). For comparison, the performance of the steel parapet selected railing was simulated under impact loading of heavy trucks, whereby no passenger car test was conducted. The parapet railing design was modelled and simulated using the SolidWorks and the NASTRAN/PATRAN software, respectively. Five case studies were derived to ensure the reliability and accuracy of the obtained results. Case 3 recorded the lowest difference percentage of 3.6% for the maximum deformation of the parapet railing. However, other case study recorded more than 10% discrepancy of the maximum deformation (i.e. Case 1, 2, 4 and 5). It can be concluded that Case 3 as the right position where the impact load exerted during the field testing. These results proved that the numerical simulation results provide a reliable result for testing the quality of the parapet railing with a minimum cost and time required, consequently, tackle the shortcomings of the field testing.

Asphalt binders have been modified with various additives and modifiers as an effort to fulfil the demand for high-performance pavements. Therefore, this study aims to investigate the engineering and leaching properties of 60/70 penetration grade asphalt binder modified with polyurethane (PU) and Cecabase additives for warm-mix asphalt (WMA) application. Measurements of the physical properties of unmodified and modified asphalt binders were made via penetration, softening point, ductility and viscosity tests. The binder-aggregate adhesivity was established by performing the Vialit test while X-Ray Diffraction (XRD) analysis was conducted to determine crystallinity of the binder. Differential Scanning Calorimetry (DSC) was used to determine thermal behavior of the asphalt binders. Synthetic precipitation leaching procedure (SPLP) test was carried out to determine the mobility of organic and inorganic elements present in the binder. PU as modifier and Cecabase as the WMA additive-enhanced binder stiffness. In contrast to Cecabase, the addition of PU increased viscosity of the binder at varying temperatures. PU also enhanced the interfacial adhesion between the binder and the aggregates. The XRD patterns showed that the incorporation of PU and Cecabase has no influence in the crystalline structure of the asphalt binders. Both PU and Cecabase have the ability to improve the workability of the binder at low temperature. The incorporation PU and Cecabase to the asphalt binder showed insignificant shift of the Tg and Tm. SPLP test results indicated that the amount of heavy metals leached out from the asphalt binder samples have no adverse effect on the environment and also did not exceed the standard for drinking.

This study was conducted to investigate the mechanical properties and water absorption of geopolymer modified bitumen. Modification of 80/100 penetration grade bitumen with the 3, 5, 7 and 9% geopolymer (by weight of bitumen) were conducted using a melt blending technique. The study of mechanical properties of geopolymer modified bitumen was conducted using impact and hardness tests. On the other hand, water absorbed behaviour of bitumen was investigated using water absorption test. The results showed that the modification of base bitumen using geopolymer has increased the strength and hardness of binder up to 108% and 82% compared to the base bitumen. The absorption amount recorded by geopolymer modified bitumen can be considered as acceptable. This study found that 5% geopolymer is the optimum content of the modifier. Therefore, geopolymer can be considered as an alternative material to modify the mechanical properties of bitumen.

This paper presents physical, thermal, and chemical analyses of polyurethane (PU) modified bitumen added with two types of warm mix asphalt (WMA) additives namely; Cecabase and Rediset. The response surface method (RSM) was used to determine the optimal amount of PU modifier in the bitumen, via central composite design (CCD). Numerical optimization showed that the optimal amount of PU in the modification of bitumen was at 3 wt%. Modified bitumen comprising of 3 wt% PU (B-PU) was then mixed with 0.5 wt% Cecabase and 0.6 wt% Rediset. These new materials were then evaluated using the penetration, softening point, ductility, viscosity and storage stability tests; thermogravimetry (TGA), Raman spectroscopy, and Fourier transform infrared (FTIR) spectroscopy analysis. Testings of the asphalt mixture include resilient modulus at different temperature and loading, and dynamic creep test was conducted to investigate the performance of modified mixtures. Results showed that PU increased the stiffness of bitumen either with or without the addition of Cecabase and Rediset. Inclusion of PU modifier into bitumen increased its viscosity, which consequently improved rutting resistance. However, adding both Cecabase and Rediset to B-PU reduced its viscosity, and this resulted in decreasing the mixing and compacting temperatures while simultaneously increasing the fatigue resistance of the mixtures. All modified bitumen were storage stable blends at high-temperatures. TGA analysis showed that the addition of PU, Cecabase and Rediset has limited effect on the thermal stability of the bitumen. Raman spectra analysis revealed that modified bitumen did not change the order structures and bee-structures of the pristine bitumen. This is consistent with result from the FTIR spectroscopy analysis, which showed the absence of chemical interaction in the modified bitumen. The addition of PU can improve resistance to fatigue and rutting at both intermediate and higher temperatures. Therefore, the addition of 3 wt% of PU showed great potential as a bitumen modifier.