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The durability and strength of concrete in construction can be significantly compromised by permeability issues, which pose considerable challenges to its long-term effectiveness and reliability. By analyzing six selected articles from the Scopus database, this study meticulously synthesizes findings on the effectiveness of CAs in improving these essential properties of concrete. The research meticulously documents and analyzes key variables such as the CA dosage, water–cement ratio, evaluation duration, and treatment conditions, providing a thorough understanding of the factors that influence the performance of CAs in concrete. The results robustly indicate that CAs significantly reduce concrete permeability, thereby enhancing its resistance to water and other detrimental substances, and simultaneously boosts the compressive strength, leading to stronger and more durable concrete structures. However, the study also reveals that the impact of CAs can vary considerably depending on the specific conditions and methodologies employed in the individual studies. This underscores the importance of standardized testing procedures to ensure consistent and comparable results across different studies. This research provides valuable insights for optimizing the use of CAs in concrete formulations, ultimately aiming to improve the durability, performance, and sustainability of concrete in construction applications.

This study investigates the field performance of Warm Mix Asphalt (WMA) road overlays containing various amounts of RAP and binder. Rutting, the International Roughness Index (IRI), and transverse, longitudinal and alligator cracking are the key parameters considered here. Our research is based on a Specific Pavement Study-10 experiment (SPS-10) conducted in nine states of North America (eight in the USA and one in Canada) that included 31 road sections in dry and wet regions. Road overlays were evaluated 1 and 4 years after their placement in terms of anti-cracking behavior and were compared with the pre-treatment status of the road. The best rutting resistance occurred at 15% and 12% RAP in dry and wet regions, respectively. For IRI, 30% and 0.0% RAP were the best for dry and wet regions as well. The maximum longitudinal crack recovery rates were found at site 3 (BA01, Arizona; dry region) and site 26 (AA65, Missouri; wet region), with RAP contents of 20% and 36%, respectively. In addition, alligator cracking did not occur post-overlay, so optimal RAP and binder contents cannot be suggested. The greatest improvements were found at site 15 (AA01, Washington state; dry) and site 30 (AA63, Oklahoma; wet). The response surface method (RSM) was also developed to explore the optimal models for RAP and selection of binder contents to minimize the rutting, IRI, and transverse and longitudinal crack lengths.

Current interest in reusing waste polymer shows substantial benefits of using it as a sustainable polymer in improving asphalt properties, attaining environmental stability and promoting industrial-economic benefits. Waste plastics have a vital role in the current asphalt applications. Trial sections of roads made with waste plastic modified asphalt, during 2019 in Australia, highlighted the significant importance of laboratory assessments yet to be conducted. As such, this study is aimed to investigate the impact of using local waste Polyethylene Terephthalate (PET) plastic in binder class C320, which is a common bitumen type used for local road surfacing in Australia. The evaluation of various contents of PET modified bitumen is carried out through two stages for unaged and aged conditions. Dynamic Shear Rheometer (DSR), Rolling Thin Film Oven (RTFOT) and Pressure Aging Vessel (PAV) tests were utilised to investigate the rutting, fatigue and aging of bitumen binder. The results showed that the ideal content of waste plastic is 6–8% to improve the rutting and aging resistances. Moreover, 8% PET improves the fatigue cracking resistance as it shows a low fatigue factor (G* sin δ). Hence, application of locally-attained plastic in pavements not only reduces the costs but also improve sustainability of environment and natural resources. Further rutting and fatigue tests on asphalt samples are recommended to better understand the mechanical properties of PET plastic on asphalt mixtures with 6–8% PET plastic. In the event that the outcomes demonstrate an enhancement in the properties of the concrete paving mixture, usage of such a material would be extremely compensating in Australia. Also, this would help decrease the amount of waste scrap plastic, in turn, sustaining the environment.

Stone mastic asphalt (SMA) has become widely used in the field of pavement engineering. Using specific additives in SMA is necessary due to climate change and load condition variations. Thus, it is essential to utilise a modern mixture with a high capacity to survive the high traffic loads. The current study aims to use a combination of waste polyethene terephthalate (PET) and Nano-silica (NS) as a newly developed hybrid additive in SMA modification to improve rutting and fatigue performance. Waste PET and NS were blended with the C320 bitumen binder by using the wet-mix process, producing SMA mixtures. The Nano-silica was added to the C320 binder (2%, 4%, 6% and 8% by weight of the binder). The engineering properties was assessed through the Marshall stability, wheel tracking test, indirect tensile strength ratio test, resilient modulus test, and drain-off tests. The results indicated that adding 4–8% of Nano-silica with 6% waste PET plastic improves the rutting performance, stiffness modulus, tensile strength ratio, and fatigue performance of the modified SMA mixtures in comparison to non-modified mixtures. The significant performance of rut depth and stiffness modulus, tensile strength ratio and drain-offs were recorded as 1.2 mm, 6100 MPa, 96.4%, and 0.04%, respectively. Results revealed that mixtures modified with the hybrid additive of 6%PET6%NS have superior performance concerning better stiffness and rutting resistance. The results showed that the increase in Nano-silica content with PET plastic increased the fatigue life to the highest extent, at up to 220,490, for the hybrid additive of 6PET6NS mixtures. Based on the results of rutting and fatigue performance, the hybrid additive of 6PET6NS mixtures reflects the optimum and ideal content. The results demonstrated that the inclusion of NS with PET successfully decreased the drain-off rates, increased the rutting resistance, and improved the fatigue life.

Using stone mastic asphalt (SMA) has increased considerably, mostly due to the improvement in serviceability of pavements. This type of asphalt mix is made with more coarse aggregates than fine aggregates. Therefore, using proper bitumen with a better coating among the aggregates is important. On the other hand, since the population grows, the production of waste materials drastically increases. Therefore, the importance of using recycled materials in other industries has increased every day. One of the most prominent types of waste materials is high-density polyethene (HDPE). HDPE is polymer waste and can improve the performance of bitumen. HDPE can be found in many municipal wastes, such as plastic bottles. Therefore, constructing pavements containing HDPE can reduce waste materials and the cost of maintaining and rehabilitating roads from the improvements of mechanical properties and performances of mixtures. This study aimed to investigate the effectiveness of HDPE on the mechanical properties and performance of SMA. Hence, Marshall properties, maximum density, bulk density, and stability were measured for the mechanical properties. Wheel tracking and four-point bending test were carried out as the performance evaluation of rutting and fatigue resistance, respectively. The results showed SMA mixtures containing 4% HDPE had the best fatigue resistance, while rutting performance was 8% HDPE. The maximum fatigue life and minimum rutting depth were recorded as 157,090 cycles and 1.05 mm, respectively.

When Portland cement (PC) is used for soil stabilisation, exposure to sodium chloride (NaCl) is a major problem in geotechnical engineering. NaCl's effect decreases the soil's structural stability and weakens its mechanical performances. The recycled powder recycled tyre (PRT) can be utilised to improve the mechanical characteristics of soil while reducing the landfills matters. The resistivity to chloride of cement clay after 7 days, 14 days and 28 days of curing were evaluated. Compressive strength tests (UCS) were performed. Half of which were performed on the control sample (unexposed) and half on the sample exposed to NaCl. The addition of 3 % PRT increased the UCS (qu) value under standard conditions and when exposed to NaCl. The same trend was observed for the addition of 5 % and 10 % PRT. The exposure reduced the UCS value, and the higher PRT dosage showed a better outcome. The analysis has shown that, when exposed to NaCl, cement hydration products, such as calcium silicate hydrate (CSH) and calcium aluminate hydrate (CAH), are degraded, causing huge voids.

Silicon, as the most abundant element in the earth’s crust and the most common material used in electronic and optical equipment, has attracted the attention of many individuals to change the properties of this material, improving its electronic and optical properties. One of these efforts relies on the reduction of surface reflection by making use of different methods. However, among them, the use of lasers in creating surface microstructures has been of special importance because there is no need for masks and other additional materials. In this work, a theoretical method is utilized to analyze these textures with the theorem of diffraction grating on a micrometer scale. The surface reflection of the microstructure created by excimer laser exposure on a silicon surface is simulated. The theoretical Coordinate transformation method (C method) gives out notable results against the experimental records by approximating triangular and trapezoidal microstructures. The model is useful for predicting the reflective response of the modified microstructural morphology. One of the main applications is the texturing of the solar cell front faces to enhance their efficiency, mainly due to photon trapping.

This study investigates effect of addition of ground recycled tyre on ammonium nitrate exposed specimens by performing a significant number of unconfined compressive strength (UCS) tests when cured at different curing periods. The results showed that addition of ground recycled tyre enhanced UCS values of control and exposed specimens for all three curing periods. The microstructural analysis encompasses XRD and SEM analysis conducted on the samples and the results showed that exposure of the specimens to the ammonium nitrate cause formation of a poor connection amongst soil, cement, and ground recycled tyre particles and a reduction on hydration product generation of the cement. The results of this study showed that the ground recycled tyre is an effective replacement for cement and can successfully applied while cement contribution is reduced, and strength of the specimens have not been compromised.

From the perspective of sustainability and environmental concerns, the use of cold-mix asphalt (CMA) and recycled asphalt pavement (RAP) is more advantageous than the use of hot mix asphalt (HMA) and warm mix asphalt (WMA). Some researchers used a mixture of CMA and RAP to improve the mechanical properties of pavement and made it more economical. However, only a few studies have focused on using a high content of RAP—particularly 100% RAP—as the virgin aggregate. Therefore, this study aims to analyse cold-mix asphalt (CMA) using 100% recycled asphalt pavement (RAP) instead of virgin aggregate raw materials and to determine the best mixture for the production of environmentally friendly asphalt. It is necessary to investigate the performance of CMA mixed with RAP in terms of the resilient modulus, indirect tensile strength, fatigue and rutting resistance. In this study, the percentage of bitumen emulsions added is 2%, 2.5%, 3%, 3.5%, and 4%, along with 100% RAP material. The results indicate that the fatigue life of the RAP mixture increased by 49.34% with the addition of bitumen emulsion (BE) from 2% to 4%, while the wheel tracking test experienced a decrease in rutting depth along with an increase in BE dose of 4%, which was 9 mm. The mixture containing 4% asphalt emulsion has the best performance. The results suggested that increasing the BE dosage increases the resistance against rutting and fatigue.

This study aims to investigate the effect and the possibility of using waste plastic as a sustainable cost-effective polymer to modify bitumen binders. Different types of waste plastic have been used in this modification, including polyethylene terephthalate (PET), high-density polyethylene (HDPE), and low-density polyethylene (LDPE). The modification targets the physical characteristics, rheological properties, and binders’ resistance to ageing. Both long- and short-term ageing are investigated to determine the durability and ageing resistance of the modified binder using rolling thin film oven tests (RTFOT) and pressure ageing vessels (PAVs). Penetration tests and dynamic shear rheometer (DSR) tests were conducted to investigate and evaluate the complex shear modulus, stiffness, elasticity, and viscous properties. The results show that 2% and 4% of HDPE and LDPE are recommended as ideal contents for good performance, as reflected by the penetration tests before and after ageing. However, higher contents, such as 6% and 8% HDPE and LDPE, are not significant in improving the stiffness, elasticity, and ageing resistance. Therefore, samples of 6–8% HDPE and LDPE are more vulnerable to permanent deformation. Furthermore, using waste PET exhibits obvious improvements in terms of the physical characteristics, rheological properties, stiffness, elasticity, and ageing resistance with up to 8% PET-modified bitumen. Based on the results, the ideal type and content is 6–8% PET waste plastic.

The construction of hundreds of kilometres of roads around the world every year results in the consumption of large amounts of raw materials and the depletion of natural resources. In addition, technologically advanced countries such as Australia are currently facing a major issue regarding the waste materials produced daily by their citizens. The disposal of these waste materials is a critical issue faced by municipalities in modern cities. Currently, using waste materials in civil and construction engineering is of great interest to researchers and industry. This study investigates the impact of using waste polyethylene terephthalate to modify asphalt mixtures following Australian design guidelines and criteria. Different types of asphalt are used to investigate and determine the mechanical properties of modified asphalt mixtures. The Marshall stability, Marshall flow, Marshall quotient, and wheel-tracking tests were tested. The Marshall stability, Marshall flow, and MQ of the Marshall test results exhibited significant improvements when using PET in modified SMA and AC mixtures. It can be seen that the 8% PET produced a mixture with the highest stability of 19.78 kN. The lowest rut depth was about 2.08 mm for samples modified with 8% PET.

Industrial waste materials are increasingly being used in asphalt to improve pavement quality and reduce environmental impacts. The aim of this research was to test the pavement distress-related effects of using ground-granulated blast-furnace slag (GGBFS) as a filler in hot mix asphalt. There is potential for GGBFS to be integrated into Western Australian (WA) asphalt pavements. GGBFS was used as a replacement for the conventional hydrated lime (HL) filler used in mix designs of the Main Roads WA specifications. A control mixture (1.5% HL) was compared with three prototype mixtures containing 1.5%, 3% or 5% GGBFS instead of HL. To investigate their characteristics, we conducted wheel tracking tests, four-point bending tests, and assessments with an asphalt mixture performance tester (AMPT). The findings support the use of GGBFS in asphalt pavements. The mixture with 3% GGBFS had the best fatigue life, rutting resistance and AMPT results.

Silty soil is abundant in alluvium deposits within urban areas, and determination of its long-term settlement characteristics is a crucial issue. This study aims to investigate the effect of four different strain rates (i.e., 1, 0.1, 0.01, 0.001 ​mm/min) on the creep and stress-relaxation behaviour of a natural type of sandy silt by performing a series of triaxial compression tests. In monotonic (reference) tests, the peak deviatoric stress increased and the volumetric strain decreased by increasing the shearing rate. The results in greater shearing rates showed that the deviatoric stress curves have a greater quasi-elastic behaviour followed by a slight yield point. Also, an almost uniform behaviour was recorded in the deviatoric stress of the specimens tested at lower shearing rates. The creep testing showed that the specimens tested at greater initial shearing rates have a greater axial strain than those tested at lower shearing rates. Also, the stress-relaxation testing showed that the specimens tested at higher shearing rates have a greater relaxation than the specimens tested at lower initial shearing rates. A comparison between particle breakages that occurred in each testing condition showed that the particle breakage index (PBI) in a monotonic condition is 1.25 and 1.5 times (in average) greater than the creep and stress-relaxation tests respectively.

This study investigates effect of coconut coir (CC) on Portland cement (PC) blended with bentonite against magnesium sulphate (MgSO4). The mixtures were bentonite clay and 3, 5 and 7% PC and 2, 4 and 6% CC when cured for 7, 14 and 28 days. A total number of 78 UCS tests were conducted on both benchmark and MgSO4 exposed samples. PC treated samples indicated an enhancement in UCS beneath all circumstances. It was also noted that the addition of 2% CC was the most effective in this research. Also, the results showed that 4 and 6% coconut coir increment to be over-reinforcement and appears create a poor bonding forces and therefore lower resistance recorded. Keywords: Oil mechanics, Sulphate attack, Clay, Cement, Coconut coir

The asphalt industry is increasingly developing with greater focus on sustainability. This study focuses on the benefits of a binder modification of stone mastic asphalt (SMA) by adding a rubber—ethylene propylene diene monomer (EPDM)—into a class 320 bitumen. This study observes the advantages that occur for the rutting and fatigue performance of the samples. The binder modification was made by incorporating 0, 2, 4 and 6% binder weight into each sample. The tests performed on the samples were the wheel-tracking test and the four-point beam bending test. The results revealed varied outcomes, with the four-point beam bending test showing the 6% sample having the highest initial stiffness and modulus of elasticity but the lowest cycle to failure. Therefore, the best performer was determined as the 4% sample, which performed consistently throughout, having the highest cumulative dissipated energy and second-highest initial flexural stiffness, modulus of elasticity and cycle to failure results. There was a clear indication of the best performer for the wheel-tracking test, with the 4% sample having the lowest rut depth, although there were signs of further improvement to be achieved within the 4–6% range. In addition, drain-off tests were conducted on the mixtures, and the addition of EPDM significantly reduced the SMA drain-off values. Overall, the best improvements through binder modification for an SMA mix with EPDM concerning fatigue and rutting resistance came from a 4% incorporation.

Commercial polymers have been used in pavement modification for decades; however, a major drawback of these polymers is their high cost. Waste plastic polymers could be used as a sustainable and cost-effective additive for improving asphalt properties, attaining combined environmental–economic benefits. Since 2019, in Australia, trial segments of roads have been built using waste materials, including plastic, requiring that laboratory evaluations first be carried out. This study aims to examine and evaluate the effect of using a domestic waste plastic, polyethylene terephthalate (PET), in modifying C320 bitumen. The assessment of several contents of PET-modified bitumen is carried out in two phases: modified bitumen binders and modified asphalt mixtures. Dynamic shear rheometer (DSR) and rolling thin film oven tests (RTFOT) were utilised to investigate the engineering properties and visco-elastic behaviour of plastic-modified bitumen binders. For evaluating the engineering properties of the plastic-modified asphalt mixtures, the Marshall stability, Marshall flow, Marshall quotient and rutting tests were conducted. The results demonstrated that 6–8% is the ideal percentage of waste plastic proposed to amend and enhance the stiffness and elasticity behaviour of asphalt binders. Furthermore, the 8% waste PET-modified asphalt mixture showed the most improvement in stability and rutting resistance, as indicated by increased Marshal stability, increased Marshall quotient and decreased rut depth. Future fatigue and modulus stiffness tests on waste plastic-modified asphalt mixtures are suggested to further investigate the mechanical properties.

Four-point bending fatigue experimental work was conducted on specimens that were cut from slabs to examine the fatigue life of concrete pavements. The variables considered were the volume fraction of fibres added in plain or steel bar reinforced concrete. It was found that the strain-based approach to fatigue testing on scaled-down concrete pavements is suitable to investigate the fatigue performance of scaled-down thin rigid pavements. The addition of fibres at 0.5% volume fraction in concrete improved the fatigue life by at least 135% and reduced the energy dissipated per cycle by 74%. As the volume fraction of fibres increased, it was found that the fatigue life of rigid pavements improved; total energy dissipation also increased but the energy dissipated per cycle was reduced in concrete pavements. This is due to the crack bridging effect of fibres that reduces the microcracking of concrete. The energy dissipation per cycle from fracture energy does not remain constant for rigid pavements under fatigue testing as it was found that the type of reinforcements influences the quantity of energy dissipated. Finally, hybrid reinforced pavements with both steel bars and fibres yielded the best performance in fatigue, with the highest number of fatigue cycles and lowest energy dissipated per cycle.

Literature has shown positive results to using waste plastic as an alternative source for PMBs where considerable interest in using waste High-density polyethylene (HDPE) has been highlighted on improving rutting resistance. Most importantly, using a waste polymer for an application has benefits (i.e., maintenance, environmental) by improving the durability and quality of our roads and by avoiding polymers from landfill or incineration. This research uses the Multiple Stress Creep Recovery (MSCR) test to assess the performance of a binder modified with waste HDPE polymer. The outcomes of this research highlights that a HDPE content of 2–4% shows a substantial increase in rutting resistance and an improvement in elastic recovery. The elastic recovery reported does improve from previous research results however it does underperform in comparison with the Styrene butadiene styrene (SBS) polymer counterpart. Furthermore, it can be indicated by the aging index that a HDPE content of greater than 4% can be detrimental to the aging effects leading to fatigue cracking. It is recommended that a combination of both waste HDPE and an elastomeric polymer such as crumb rubber is to be used in future test work to improve the elastic recovery and address the effects of fatigue cracking.

Nine alkali-activated concrete beams were produced and tested under pure torsional load to failure. The alkali-activated concrete beams were produced with following variables: (i) fibres only, (ii) conventionally reinforced or (iii) a hybrid of both fibres and conventional steel reinforcement. The fibres only beams were found to have approximately 20% higher cracking torque than conventionally reinforced beams. However, fibres only beams were observed to have lower post crack ductility and inconsistent post crack behaviour, in comparison to conventionally reinforced alkali-activated concrete (AAC) beams. On the other hand, the hybrid reinforcements in AAC beams were found to demonstrate more ductile post crack behaviour consistently of the beams tested. Hybrid reinforcement was also shown to have 20% and 25% improvement in cracking and ultimate torque compared to conventionally reinforced, which suggests that it is suitable for industrial applications to improve structure capacity. The ultimate torque results of the beams were compared to an analytical model that considered the contribution of fibres. It was found that the ultimate torque of the hybrid reinforced beam has good correlation with the model but overestimated conventionally reinforced beams.

Atrazine (ATZ) is one of the most heavily used types of herbicide that is currently applied in the agricultural industry all around the world, especially Australia and the United States. This study investigates the effect of atrazine contamination on the mechanical characteristics of two Western Australian natural clays and one commercial type of clay. A series of the Atterberg limit, compaction, and torsional ring shear tests were performed on the clays contaminated with 2, 4, and 6% atrazine content. The results showed that increasing the atrazine content led to a reduction in both liquid limit (LL) and plastic (PL) of the tested soils. Similarly, the optimum moisture content (OMC) and maximum dry density (MDD) decreased by increasing the atrazine in all tested clays. The ring shear results showed that the peak shear strength and residual stress ratio of the clays decreased by increasing the contamination. Also, the results showed that atrazine contamination caused an increase in cohesion and a decrease in the friction angle of the tested soils. Also, longer periods of contamination caused a reduction in strength characteristics of the tested soils.

Application of sawdust in civil engineering projects, specifically those with geotechnical applications, has been the interest of many studies. This study focuses on exposure of soil samples treated with sawdust to MgSO4. This study was conducted in three stages. The first stage was compaction. In this stage, the compaction characteristics of each mixture were derived. The second stage was to run unconfined compressive strength (UCS) testing and report the UCS peaks relevant to each mixture. The third stage was microstructural examination (i.e., SEM) conducted on the chosen samples before and after sulphate exposure to highlight the reactions during exposure. The results of first stage (i.e., compaction tests) suggested that increasing sawdust content, the OMC (Optimum moisture content) decreased and MDD (Maximum dry density) decreased. In the second stage, the UCS (Unconfined compressive strength) testing was conducted on 640 samples [including reliability tests] and the outcome suggested that sawdust increased the resistance of samples against sulphate attack. In stage three, the micro analysis backed the main body results, suggesting that sawdust had a positive effect on helping to form a better connection between the particles and therefore more resistance noted.

This paper presents the results of an investigation into the impact of ship berthing upon floating piers using highly advanced numerical software Abaqus. The ship and floating piers were modeled as solid bodies. For the first time, the effect of soil on the total energy absorption of the system was considered using both elastic and elastic-perfectly plastic soil models. First the results for the elastic soil model were compared to and verified by the existing literature using a spring soil model.Then a continuum soil model was utilized instead of a spring soil model, with the results showing 27% higher energy absorption compared to the spring model. The investigation also considered a model with soil as an elastic-perfectly plastic material, being more aligned with the soil material’s real behavior. With this model the results produced 1% more energy absorption as the soil did not reach plastic failure.