Journal of Materials in Civil Engineering

This study evaluated potential improvements in the physical and rheological properties of asphalt binders modified with crumb tire rubber (CTR), microcrystalline synthetic wax (MSW), and nanosilica (NS). Asphalt binder with $85/100$ penetration grade was used. A statistical analysis of the experimental data was performed to determine the effect of using CTR, MSW, and NS on $60/70$ and $85/100$ asphalt binder grades and to detect any differences. Both physical and rheological tests of pure and modified asphalt binders were conducted. The physical tests were the penetration test, softening point test, and flash and fire points test, whereas the rheological tests included the rotational viscometer (RV) test, dynamic shear rheometer (DSR) test, and bending beam rheometer (BBR) test. The results showed that adding CTR and NS enhanced the high-temperature performance, but it had no effect on low-temperature performance. The results did not indicate enhancement by MSW of high-temperature performance but indicated a negative effect on low-temperature performance. The experimental results were compared and analyzed statistically by ANOVA to find any significant differences between the effect of modifier type, binder grade, and test temperature. Based on the one-way ANOVA results, the modifier type had a significant effect on physical properties and rotational viscosity. The two-way ANOVA results revealed that the change in modifier type and binder grade together had a significant effect on flash point and rutting parameter for unaged samples at 58°C only. The three-way ANOVA indicated that changing the modifier type, binder grade, and test temperature all together had a noticeable effect on the BBR m-value test results.

The purpose of this research is to study the influence of aspect ratio and end conditions on the strength and failure mode of remolded soil samples in unconfined compressive strength tests. The digital image correlation method is used in this research to obtain the evolution process of the horizontal displacement field in remolded soil samples and analyze the deformation and failure characteristics in various sample sizes. Two-dimensional discrete element models of the soil samples are established to simulate the impact of different end-frictional conditions on stress-strain processes of samples. Results show that, with the growth of aspect ratios, the failure of samples transforms from tensile mode to shear mode, and the defects in the middle of samples become more obvious. Characteristic values of earthen sites’ soil, such as peak strain, elastic modulus, and residual stress, change with various aspect ratios. The simulation results are in accordance with typical experiments, thus verifying the rationality of established discrete element models. By comparing the particle displacement directions and the respective proportions, the constraint caused by loading plate on samples is proved to be one of the reasons for the size effect. When the aspect ratio is higher than 1.0, the size effect disappears in end-frictionless samples. The research has practical significance to deepen understanding of the mechanism for unconfined compressive strength of site soil samples and provides scientific references for protection and reinforcement of earthen sites.

Recently, a new test method, multiple stress creep and recovery (MSCR), was suggested to improve the current performance binder tests. In the MSCR test method, the behavior of binders in high temperatures was evaluated. One of the advantages of this new specification was to better capture the rutting behavior of binders. The aim of this research was to investigate the rheological behavior of modified binders through MSCR and a performance grade (PG) test and compare the results of grading binders through two different methods of MSCR and PG systems. In order to modify the original binder, the warm additives (Sasobit, Rheofalt, and Zycotherm) were used in this study. Results demonstrated that warm additives improve the rheological behavior of the original binder. The results of two parameters [nonrecoverable creep compliance ($J_{nr}$) and percent recovery ($R\%$)], which derived from MSCR test, indicated that $J_{nr}$ decreases and $R\%$ of binders increase. In comparison with modified binders, binders modified with 3% Sasobit (S) have the lowest $J_{nr}$ and highest percent recovery value, which gives rise to the original binder to better resistance against rutting. According to the PG method, binders containing 3% additive S can be used in all climatic regions in Iran.

An environmentally friendly concrete is of high interest to develop because the production of portland cement as the main binder of conventional concrete is associated with generating a large amount of carbon dioxide. As a green and eligible alternative to conventional concrete, geopolymer concrete (GC) has been invented and studied over the past 2 decades. This experimental study was aimed to take one step further by examining the possibility of developing lightweight, rubberized, and lightweight rubberized geopolymer concrete. In the first step, a control mix was established for GC suitable to be cured at ambient temperature as it is necessary to promote its usage in the construction industry. Afterward, lightweight geopolymer concrete (LWGC) was developed by replacing fine aggregates with expanded polystyrene beads (called BST) at 25%, 50%, 75%, and 100% ratios by volume. Then rubberized geopolymer concrete (RGC) was produced by 10% and 20% natural aggregate replacement by volume with crumb rubber (CR) aggregate, which is another pollution source to the global environment. Finally, the possibility of developing lightweight rubberized geopolymer concrete (LWRGC) was examined using BST and CR aggregates. The performance of developed GCs is discussed based on slump flow, density, compressive, tensile, and flexural strength at 7 and 28 days in this paper. The optimal mix design concluded from LWGC and RGC mixes is also introduced for LWRGC with two different CR sizes (2–5 mm and 5–10 mm). The proposed green mixes showing acceptable fresh and hardened mechanical properties are able to be used in appropriate construction projects and hence reduce the need for cement manufacture as well as disposal of end life tires.

This study presents results on the influence of silica fume (SF) and additives on the unconfined compressive strength (UCS) of ordinary portland cement (OPC)-stabilized salt-rich marine soft clay. The effects of additives including sodium hydroxide (SH), calcium chloride (CC), weed ash (WA), eggshell powder (EP), weed ash (WA)/calcium chloride (CC), weed ash (WA)/eggshell powder (EP) and sodium hydroxide (SH)/calcium chloride (CC) on the engineering properties of salt-rich marine soft clay are investigated and evaluated. The influencing factors included in this paper are the type of additive, the additive dose, the proportion of each additive, and the curing time. The results of the investigation reveal that a single additive of sodium hydroxide or weed ash are more effective than using other additives. By adding sodium hydroxide or weed ash, the strength (at 28 days) of marine soft clay can be increased by 102.10% or 90.70%, respectively, over that without additives. However, with the addition of an increasing amount of calcium chloride, the strength of the stabilized soil slowly decreases. The influence of EP on the strength of marine soft clay is not significant. Compared with the effect of a single additive of sodium hydroxide or weed ash, the selected composite additives—namely, weed ash/calcium chloride, weed ash/EP, and sodium hydroxide/calcium chloride—could not achieve a higher strength. Based on an orthogonal experiment, the OPC-based composite stabilizer with the best stabilization performance is selected. Compared with OPC, the composite stabilizer is more effective and eco-friendly. The investigation results show that the strength of the 5.00% OPC and composite stabilizer could exceed the strength of the clay with only 10.00% OPC. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) tests are conducted to reveal the influence and stabilization mechanisms.

Liquid antistripping agents are added to asphalt binder to improve moisture resistance of the mixture. However, the chemical makeup and bonding mechanism of antistripping agents may cause significant effects on binder rheology. This paper investigates the effects of two different liquid antistripping agents, one amine based and another silane based, on the rheological properties of crumb rubber–modified binder CRMB60. Rheological properties determined included rotational viscosity, performance grade (PG), percent recovery, nonrecoverable creep compliance, creep stiffness, and rate of relaxation. The number of cycles to fatigue failure aided in evaluating the fatigue life. The results show that the addition of antistripping agents caused a decrease in rotational viscosity of CRMB60. Moreover, the silane antistripping agent was observed to cause a bump in high-temperature PG, whereas low-temperature PG remained unaffected by both antistripping agents. The multiple stress creep and recovery (MSCR) analysis exhibited that the silane antistripping agent increased the percent recovery and decreased the nonrecoverable creep compliance, whereas the contrary trend was observed with addition of the amine antistripping agent. Both the amine and silane antistripping agents caused a significant decrease in the fatigue life of CRMB60. Additionally, minor effect was observed on low-temperature cracking performance by both the amine and silane antistripping agents up to a certain temperature below which the cracking exacerbates. Overall, it was concluded that antistripping agents affect the rheology of CRMB60 and should be given due consideration prior to adopting a particular antistripping agent.

In order to study the effects of steel slag on the mechanical properties and microstructure of geopolymers, the compressive strength and flexural strength of a fly-ash steel slag–based geopolymer paste/mortar have been explored. Linear analysis of strength of fly-ash steel slag–based geopolymeric mortar with steel slag content was studied. The microstructure and mechanism of fly-ash steel slag–based geopolymer were measured by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and field emission-scanning electron microscope (FE-SEM). The pore structure was tested by the Brunauer-Emmett-Teller (BET) method. The results show that the early strength of geopolymers shows an upward trend with the increase of steel slag content, however, in the later age, the compressive strength of the sample gradually decreases when the steel slag content exceeds 10%. FT-IR and XRD results indicate that both sodium aluminosilicate hydrate (N-A-S-H) gel and calcium aluminosilicate hydrate(C-S-H) gel exist in the fly-ash steel slag–based geopolymer. BET and FE-SEM results show that compared with the control sample (FAP-0), more mesopores and fewer macropores are present in the paste sample with 30% steel slag (FAP-30).

Concrete admixtures are constantly used in construction projects, and these admixtures can be used to increase/decrease the setting time, improve workability, enhance frost and sulfate resistance, and to help control strength development. The quality of admixtures play a crucial role in altering fresh concrete properties. To streamline such quality control process for regular inspections, two key procedures are necessary: (1) collection and maintenance of the baseline approved admixtures quality, and (2) usage of sound analysis tools and procedures for quality verification of newly supplied materials. However, relying on manual comparison by the naked eye makes the identification process very tedious and inaccurate due to similar patterns of admixture infrared spectrophotometry (IR) signatures. Therefore, an efficient and standardized system is necessary for an accurate quality control process. In this study, advanced quality control models are investigated and proposed by utilizing the pattern-recognition methodology using artificial neural networks (ANNs) by utilizing data-driven and self-adaptive functions and other advanced machine-learning techniques for the pattern classification function. The feasibility of the proposed models were evaluated for the automatic quality control process. To identify a mixture’s chemical and physical properties, energy absorption is measured at each wave number through the amount of transmitted infrared light. Developed pattern-recognition ANNs and other machine-learning models have shown their efficiency in learning and identifying the admixtures’ IR signature spectra. Hence, the proposed advanced quality control models can be a very useful tool to determine the admixtures’ quality accurately and quickly and eventually to guarantee their intended performance in altering the concrete’s properties.

The eco-efficiency and economy of geopolymer composites largely depend on their alkaline activator dosage. In this study, the effect of applying a pre-setting pressure and variation of the aggregate-to-fly ash ratio on the alkaline solution dosage and mechanical strength of fly ash–based geopolymer composites was explored. It is shown that through control of the aggregate-to-ash ratio and application of pre-setting pressure, compressive strength could be increased by 102% and 86% for Class F fly ash–based geopolymer and alkali-activated Class C fly ash–based mixture, respectively. The total alkaline solution consumption could be reduced from 718 to $188\mathrm{kg}/{\mathrm{m}}^3$ and from 769 to $262\mathrm{kg}/{\mathrm{m}}^3$ for Class F fly ash–based geopolymer and alkali-activated Class C fly ash–based mixture, respectively. The proposed method reduced the alkaline solution consumption per compressive strength ($6.2\mathrm{kg}·{\mathrm{m}}^{-3}·{\mathrm{MPa}}^{-1}$) by up to 85% compared to that of the reference manually consolidated control geopolymer. The findings demonstrate that fly ash–based geopolymers could be made more sustainable and eco-efficient through tailored production techniques.

Rutting of asphalt pavement is the accumulation of plastic deformations and is one of its major distresses and concerns. To date, rutting of asphalt pavement cannot be accurately predicted because of the complex material behavior. The repeated-load test was deemed to be a good method for asphalt concrete rutting analysis. In this paper, the strain recovery characteristic of the asphalt mixture is studied to reflect material rutting resistance based on the repeated-load test. Fiber Bragg grating-based three-dimensional (3D) strain measurement equipment was used to synchronously measure the vertical and lateral strain of the test specimen. The rutting resistance evaluation method was demonstrated through an analysis of the repeated-load test data of four types of asphalt mixtures with nanosized volcanic ash fine fillers. A new phase angle calculation model was developed, and the calculated strain curve based on this model coincides well with the test data. The calculated phase angle of the asphalt mixtures used in this paper is two times larger than that obtained from the traditional direct curve comparison method. A new indicator, the ratio of residual strain (RRS), which is not influenced by the aggregate skeleton, was used for the rutting resistance evaluation of all of the materials. The mechanism of the generation of plastic deformation was also analyzed based on the test data.

Rubber particles can become compressed during testing of asphalt binders modified with crumb rubber (CR) in dynamic shear rheometer (DSR) parallel-plate geometry. This is especially true at high concentrations and/or large CR sizes. There have been claims in the literature that this compressed condition does not represent the true properties of CR-binder suspension rheology. This has resulted in questioning the applicability of the Superpave performance grading (PG) procedure to these binders. An alternative test geometry commonly used in the food industry, concentric cylinder geometry, was proposed to allow for better suspension of CR during testing. However, because CR particles are compressed within an asphalt mixture, binder properties measured using parallel plates may correlate better to mixture properties than those obtained by the concentric cylinder. In this study, a comparative analysis was conducted for the dynamic shear moduli of CR-modified binders measured using these two DSR geometries. The modified binders were produced with different CR concentrations and sizes. Comparisons were also made with dynamic moduli of mixtures produced with these different binders. It was observed that parallel plates correlate to mixture properties as good as or better than the concentric cylinder geometry.

Road construction consumes vast quantities of high-quality quarry materials. Lateritic soil (LS) is commonly used as a natural resource for subbase and base materials in Thailand. This research aims to study the feasibility of using crushed slag (CS) and fly ash (FA) to improve the physical properties of marginal LS prior to cement (C) stabilization for pavement applications. The pozzolanic materials in CS and FA were found to react with $\mathrm{Ca}(\mathrm{OH}{)}_2$ produced by hydration, which results in the formation of cementitious products over time. Geotechnical engineering laboratory tests were conducted to evaluate the possibility of using cement stabilized LS/CS/FA blends as pavement subbase/base materials. The durability of the blends against wetting and drying cycles were also studied. The unconfined compressive strength (UCS) development of the mixtures was examined by using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. CS was found to have a high potential for minimizing swelling, which controls the durability of the stabilized material. Based on the specification of the Department of Highways, Thailand, the 3% C samples were found to be suitable as a subbase material when blended with 30% CS replacement and as a base material when blended with CS and FA at $\mathrm{LS}:\mathrm{CS}:\mathrm{FA}=70:0:30$ and $70:15:15$. The CS replacement was found to prolong the service life of stabilized subbases/bases with up to 12 wetting-drying cycles. This research confirms the possibility of incorporating LS/CS/FA in road work applications, with significant environmental benefits.

This study reports the combined effects of fly ashes, hemp fibers, and shives on the strength performance of modified mortars. Fly ashes are first processed using high-intensity mechanical milling. Natural fibers are observed using X-ray microtomography to reveal the microstructural arrangement. Preliminary formulations are attempted with different proportions of hemp fibers and shives up to 4%. X-ray diffraction, infrared, and thermal gravimetric analysis (TGA) methods are used to reveal the main structural changes in modified cement pastes. Workability and strength characteristics of various formulations are evaluated for ranking. The best performing modified mortars are selected based on their strength performance to formulate the mix proportions of milled fly ash and cement mortar. The experimental results demonstrate the beneficial effect of adding hemp fibers with shiv to achieve acceptable workability. In addition, it was found that the optimal hemp content in modified mortar was 3%. This amount minimizes the negative effect of natural additions on mechanical strength. Finally, fly ashes are found to be an efficient leverage to formulate modified mortars exhibiting a strength performance superior to that of the reference mortar.

In this study, recycled coarse aggregate concrete (RAC) with incorporation of high-performance water-reducer and air-entraining agent was designed with a water to cement ratio of 0.25. Rapid salt-frost tests were conducted on the RAC specimens, during which mass loss and relative dynamic modulus of elasticity of the RAC specimens after salt-frost cycles (SFC) were obtained. Cubic compressive strength, splitting tensile strength, and uniaxial compression stress–strain curve of the RAC after SFC were also obtained. The loss of mass and relative dynamic modulus of elasticity of the RAC after 250 SFC was 0.5% and 19.31%, respectively; both much lower than the corresponding critical failure values of 5% and 40%, respectively. The cubic compressive strength, splitting tensile strength, peak stress, and modulus of elasticity of the RAC after SFC were found to decrease with the increase in the number of SFC, by 56.9%, 41.3%, 7.9%, and 15.0%, respectively, after 250 SFC. The elastic Poisson ratio and peak strain of the RAC after 0–250 SFC varied slightly around 0.22 and 2,200 με, respectively. In addition, the equations for describing the uniaxial compression stress–strain curve of the RAC after 0–250 SFC are presented, which fit well with the experimental results.

The feasibility of using red mud as an alkali source in alkali-activated fly ash and Portland cement (PC) based binary binder for controlled low-strength material (CLSM) is investigated. The alkalis in red mud are NaOH and ${\mathrm{Na}}_2{\mathrm{CO}}_3$. The inclusion of red mud increases the pH value of pore solutions in the mixtures by direct dissolution of NaOH and reaction of ${\mathrm{Na}}_2{\mathrm{CO}}_3$ with portlandite formed in PC hydration. The mixture with increased pH value accelerates the hydration of fly ash and PC based binary binder, contributing to the strength development of CLSM. The red mud also acts as a micro-filler that refines the pore structure and thus reduces the concentration of harmful pores ($\ge 50\mathrm{nm}$). The engineering performance is enhanced with inclusion of red mud, which is mainly attributed to the accelerated hydration of the binary binder and the refined pore structure.

Viscosity modifying admixtures (VMAs) show great potential in achieving the desired rheological properties for 3D concrete printing. In addition to rheology, water transport properties are critically important; due to the absence of formwork, freshly printed components with high exposed surface areas are susceptible to excessive water loss. In this study, the effect of VMAs (i.e., attapulgite/palygorskite nanoclay and diutan gum) on the water transport properties of cement pastes were investigated. Bleeding, water retention under suction pressure, and evaporation under airflow were measured. The nanoclay was found to reduce bleeding but had no effect on water retention or evaporation. The diutan gum was found to reduce bleeding, improve water retention, and decrease evaporation loss. The potential working mechanisms of nanoclay and diutan gum are discussed and tied to observations of the rheological and water transport properties of the modified pastes.

Asphalt is a kind of temperature-sensitive material, and the temperature stability of asphalt mixtures is not very good. The production of hot-mix asphalt mixtures consumes a substantial amount of energy and produces carbon dioxide (${\mathrm{CO}}_2$) emissions. Polyurethane (PU) mixtures have better high-temperature stability and durability. Besides, the production of PU mixtures can save energy and reduce ${\mathrm{CO}}_2$ emissions because the materials can be prepared at room temperature. However, traditional mixture structures were not suitable for PU binders. In this work, the GB5 mix design was used to decrease the influence of boundary interactions and discrete interactions on the void ratio of aggregates; therefore, a PU mixture with a skeleton-interlocking structure (PUM) was prepared. Properties and functional groups of the PU were assessed by use of the Brookfield rotational viscosity test, Fourier transform infrared spectroscopy (FTIR), and dynamic mechanical analysis (DMA). The high- and low-temperature stability, water stability, and fatigue resistance of mixtures were evaluated by use of the wheel-tracking test, low-temperature bending test, freeze-thaw splitting test, and fatigue test. Results suggested that the PU material was the prepolymer of isocyanate and polyhydric alcohols, and the isocyanate group was present in excess. Higher construction temperatures were indicative of shorter operating times of PUM. Additionally, 3% retarder of PU can prolong the allowable operating time for 5–10 min, and 5% retarder can prolong for 10–20 min. Measurements of PUM met requirements for hot-mixed modified-asphalt mixtures. The low-temperature stability, water stability, and fatigue resistance of PUM were improved when compared with other mixtures. In addition, PUM demonstrated excellent high-temperature stability.

Asphalt mixtures made with recycled concrete aggregates (RCAs) derived from construction and demolition (C&D) wastes exhibits inferior properties to mixtures containing natural aggregates only. This is mainly because of old cement mortar attached to RCA surfaces, and other impurities such as bricks and tiles. This study developed a new state-of-the-art coating technique to improve the behavior of RCA–asphalt mixtures. The technique was based on combining two treatments: coating and heating. It is therefore called the double-coating technique (DCT). The coarse RCA was first coated with bitumen emulsion to upgrade its durability. However, postcoating, some areas of RCA surfaces were found not coated with bitumen emulsion. Therefore, asphalt mixtures made with such particles were cured in an oven maintained at 155°C for 90 min. The bitumen is expected to be less viscous at 155°C, and flowed through the uncoated areas and sealed them. A second treatment was applied to minimize the expected moisture degradation and improve adhesion between RCAs and bitumen. The treated RCA is called double-coated recycled concrete aggregate (DCRCA). Mixes with 0%, 20%, 40%, and 60% DCRCAs were evaluated. The use of DCRCAs was found to improve the resistance of asphalt mixes against permanent deformation. The fatigue life (number of cycles to failure) also was improved by the addition of DCRCAs in asphalt mixtures. The number of load cycles of DCRCA mixes was 12%, 23%, and 141% higher than that of the control mix. The DCRCA mixes exhibited either comparable or better dynamic modulus than that of control mix. Although the use of RCAs in flexible pavement construction is not yet permitted in Australia, the results presented in this work indicate the suitability of DCRCAs to be used in asphalt mixtures production.

Lateral swelling pressure (LSP) of expansive soils included in the total lateral pressure (TLP) often results in instability and even sliding failure of retaining walls. In this study, a modified oedometer was developed and adopted to overcome certain limitations in previous laboratory swelling tests on expansive soils. A method for measuring LSP is proposed. TLPs of medium expansive soils samples were measured under different water contents, dry unit weights, and immersion vertical pressures. From experimental results, it was indicated that the ratio of LSP to vertical swelling pressure (VSP) at a constant volume of expansive soils with different initial water contents ranged from 0.27 to 0.31. A case study was carried out to investigate the stability of a 3-m-high gravity retaining wall backfilled with expansive soils. In active state, the larger resultant force of LSP is two times of that of active earth pressure on the retaining wall, resulting in sliding failure of retaining wall.

To render thermal-resistant aggregates more suitable in asphalt mixtures, the optimal process for treating three typical thermal-resistant aggregates—shale ceramsite (SC), porous volcanic rock (PVR), and refractory gravel (RG)—with two organic treatment agents—silicone resin (SR) and silicone–acrylic (SA) emulsion—was determined according to the basic properties test. Further, the best agent for different aggregates was recommended according to a scanning electron microscopy and road performance. The results indicate that the optimum concentrations of SR for SC, PVR, and RG are 25%, 25%, and 15%, respectively, and the curing temperature is 160°C. In contrast, the optimum concentrations of the SA emulsion are 35%, 25%, and 15%, respectively, the additive content is 3%, and the film formation temperature is 30°C. Furthermore, the surface package effect of SR-treated aggregates is better than that of the SA-treated aggregates. Both agents can improve the road performance of thermal-resistant aggregates. Finally, using SR to treat SCs and PVRs, and to treat RGs with a SA emulsion, is recommended.

With the advent of new materials that possess enhanced properties, designing concrete mixtures targeting a certain strength is a misleading concept. Hence, shifting to performance-based design is becoming a global trend that allows more flexibility in selecting and proportioning concrete ingredients. This study investigates the potential of increasing electric resistivity for fiber-reinforced concrete (i.e., reducing corrosion risk) while maintaining adequate strength. The key parameters included mixture ingredients, electrical conductivity, and physical properties of the used fibers. Two categories of fibers were considered: conductive (steel fiber) and nonconductive fibers (i.e., polypropylene and nylon). These fibers were incorporated in concrete mixtures with and without silica fume. Compressive and splitting tensile strengths, rapid chloride penetration, bulk, and surface electric resistivity were evaluated for all tested mixtures in order to illustrate potential interactions. Results show that there is a high potential to achieve highly electrically resistant concrete with adequate strength through the use of nonconductive fibers. Moreover, results emphasize the beneficial synergistic effect of nonconductive fibers and silica fume in optimizing the performance. Developed relationships between mechanical properties and electric resistivity are anticipated to guide engineers in selecting suitable mixtures based on the targeted performance.

Based on the long-term maintenance data, the performance and service lives of several orthotropic steel bridge deck (OSBD) pavement materials in long-span suspension bridges were studied and evaluated. According to the results, the pavement service life was found to have a strong relationship with traffic volume, so limiting overload of vehicles is an effective means to ensure the performance and prolong the pavement service life. Gussasphalt (GA) and ordinary road pavement asphalt mixtures cannot meet the requirement of OSBD pavement in suspension bridges, and cold-mixed resin-asphalt concretes are expensive and their application effects were not excellent enough. High-resilience polymer and rubber-modified asphalt concrete can be used as an alternative material in the maintenance of OSBD pavement because of their acceptable service life and proper cost. Epoxy asphalt concretes (EAC) were found to be the most successful materials in suspension bridge OSBD pavements. One kind of EAC, named Kindai Bridge Epoxy Pavement (KD-BEP), was confirmed to be more suitable for the maintenance of long-span suspension bridges’ OSBD pavement because of its simpler construction process, shorter curing period, and more stable quality.

Creep effect becomes an important consideration in the design of high-strength steel structures subjected to a soaking period at elevated temperatures such as in stress-relieving post-weld heat treatment (PWHT) circumstances. However, very limited experimental data can be found for the creep property of the thermal-mechanical control process (TMCP) of high-strength steel (HSS) at different elevated temperatures and stress levels, which seriously restricts the numerical modelling for the creep effect and analysis of the mechanical behavior of TMCP HSS structural elements. To this end, the physical mechanisms underlying the creep in TMCP HSS were firstly discussed in this paper, after which the mechanical properties of Q690CFD at ambient and elevated temperatures were investigated. An experimental investigation on the creep properties of Q690CFD at elevated temperatures was organized in the current study. The effect of environmental temperature and stress level on the creep behavior of TMCP HSS was also studied. A constitutive model was proposed to describe the creep behavior of TMCP HSS under elevated temperatures. Finally, validation of the constitutive model shows good agreement with the test results.

Aluminum alloys are increasingly applied in spatial structures owing to their light weight and favorable ductility. The study on mechanical properties at different temperatures is of significance in studying the behavior of aluminum alloy structures under extreme conditions. In this study, tensile tests on certain brands of aluminum alloys commonly used in spatial structures were performed at temperatures ranged from $-100°\mathrm{C}$ to 300°C. The elastic modulus, ultimate strength, nominal yield strength, and elongation of the specimens were obtained. It was revealed that aluminum alloys perform improvement in both strength and ductility at low temperatures, and the mechanical properties of aluminum alloys drop rapidly at high temperatures. Subsequently, the constitutive relationship of aluminum alloys at different temperatures was investigated. Moreover, fracture analysis carried out through scanning electron microscope (SEM) indicated different microscopic mechanisms at extreme temperatures. Finally, the temperature influence factor for mechanical properties, which are necessary in spatial structure design, were proposed.

Current laboratory procedures to predict the erosion potential of cohesive geomaterials test undisturbed or remolded samples at ambient laboratory temperatures, which may not represent field conditions. This paper analyzed the effects of both water and soil temperatures on cohesive soil erosion. Remolded cohesive soil samples were tested in an erosion function apparatus at independently controlled water and soil temperatures. The findings showed that testing at ambient laboratory conditions may underestimate in situ erosion when higher temperatures are experienced in the field. Furthermore, the results indicated that the water temperature influences erosion more than does soil temperature alone due to convective heat transfer between the water and soil. The recommendation from this study is that the water temperature be controlled in laboratory erosion testing at the maximum anticipated temperatures in the field.