Journal of Materials in Civil Engineering

This study compares the durability, in terms of resistance to corrosion, of strain-hardening fiber-reinforced cement-based composite (SHCC) and the same matrix without fiber (mortar). The corrosion mass loss of embedded steel bars and the cracking behavior of specimens under the influence of varied applied voltages and concrete cover depths were investigated. The relationship between the crack width and cover depth and its relation to corrosion mass loss is established. The study has been performed through an accelerated corrosion test. The test setup involved the placement of the reinforced SHCC and mortar prism specimens in a 5% (by weight) sodium chloride solution and then applying various direct currents (DC) by a power source in the range of 10–30 V to the specimens to accelerate the corrosion process. Actual and estimated corrosion mass losses (using Faraday’s equation) at different concrete cover depths were also compared. The result has shown that applied voltage and concrete cover depth have significant effects on the corrosion mass loss and cracking behavior of SHCC and mortar. However, mortar specimens had significantly higher crack widths than SHCC specimens.

To mitigate flood damage in cities, pervious concrete has been developed as a viable and sustainable alternative to traditional concrete to facilitate drainage. Previous studies have tended to evaluate the drainage capacity of pervious blocks through permeability and drainage tests in simplified conditions, giving little consideration to multiple environmental factors such as rainfall rate and temporal changes in the blocks’ drainage capacity. This study presents experimental results of the runoff and drainage capacity of pervious blocks subjected to time-dependent evaporation and corresponding changes in their degree of saturation. Different levels of repeated water charging at designated time intervals simulated the urban environment, and both runoff and drainage were continuously monitored. The results highlight that runoff can take place after certain time intervals despite the same water charge because of evaporation and prewetting-induced changes in water-retention capacity. The effects of the surface layer, the bedding layer, and clogging (all part of the urban areas) on the drainage were also observed. The findings underscore the significance of the actual, rather than the simplified laboratory-based, drainage capacity in urban areas.

This paper presents the results of an experimental investigation of the strength, permeability, abrasion, carbonation, and shrinkage characteristics of concrete containing various percentages of copper tailing as partial replacement of natural fine aggregates. M 25 Grade concrete was designed as per specific national specifications. Copper tailing was used to replace natural sand in the range of 0–80%. It was observed that the copper-tailing concrete with up to 80% substitution exhibited a comparable compressive and flexural strength when compared to the control specimens. From the abrasion test, it was noted that the specimens could be implemented in general-purpose and heavy-duty floor tiles. The shrinkage strains, water permeability, and carbonation of copper-tailing concrete were observed to be increasing with increasing replacement amounts of copper tailing. The concrete containing copper tailing replacing up to 70% of natural fine aggregates could be recommended for all applications, and substitution levels beyond 70% could be recommended for nonstructural applications, pavements, etc.

Nanosilica powder was added to modify the properties of epoxy binder. Two types of modified epoxy resin binder [crack glue and fiber-reinforced plastic (FRP) glue] are developed to repair cracks and to glue fiber fabrics to the concrete surface, respectively. Bonding strength of FRP concrete interface is tested, the flexural strength test for FRP-strengthened cracked concrete is conducted, and the effects of FRP dimensions, concrete strengths, and types of premade crack and epoxy binder on strengthening are analyzed. Nanosilica powder greatly improves the ductility, strength, and workability of epoxy binders. Effective bonding between FRP and concrete can be achieved by nanomodified FRP glue. Nanomodified crack glue is able to repair concrete containing cracks without diminishing concrete capacity. The failure regions are beyond the premade cracks. The ultimate capacity, ultimate displacement, and fracture energy of cracked concrete are significantly improved by strengthening with crack glue and FRP.

Warm mix asphalt (WMA) and recycled asphalt pavements (RAP) are two popularly used sustainable technologies in pavement industry. Because RAP materials contain aged binder, its use is limited to a certain percentage in hot mix asphalt (HMA) as it may affect the workability and, fatigue and thermal cracking performance. Higher percentages of RAP can be incorporated into HMA with softer asphalt binder or in combination with softening agent. However, the combination of WMA and RAP may allow for greater percentages of RAP without modifying the original HMA job mix formula. The objective of this study was to explore the use of higher percentage of RAP, using two different WMA technologies—Evotherm additive and foamed asphalt—to study the workability and moisture sensitivity of WMA-RAP asphalt mixtures. The study found that the use of WMA technologies can eliminate the need for a softer grade binder in high RAP mixtures.

An effort is being carried out to encompass the influence of molding moisture content ($\omega$) on the dose procedures aimed at binder enhanced fine-grained soils built on sound criteria. The porosity/cement index ($\eta /C_{iv}$) plays an essential role in initial shear stiffness ($G_0$), tensile ($q_t$), and compressive ($q_u$) strength, and triaxial failure envelope parameters determination. This study aims to assess $G_0$, $q_t$, $q_u$, $q_t/q_u$ and $G_0/q_u$ relationships of fine-grained soils treated with distinct cement amounts, distinguishing dry densities and different molding moisture contents to show that the effect of distinct structures because of the influence of moisture content and the porosity/cement index play a major function in establishing stiffness and resistance of fine-grained materials. The ruling factors assessed were molding moisture content and adjusted porosity/cement index. Ultrasonic pulse velocity, unconfined compression, split tensile and drained triaxial tests were performed in current research. Higher values of parameters $G_0$, $q_t$, and $q_u$ are observed with the rise of binder content and reduction of porosity of the compacted mixture. In addition power functions are used to represent these interaction diagrams relating $G_0$, $q_t$, or $q_u$ with cement content or porosity/cement index. Therefore, the porosity/cement index is shown to be suitable to evaluate $G_0$, $q_u$, and $q_t$ of the fine-grained soil-binder blend studied. $q_t/q_u$ ends to be independent of parameters $\eta /C_{iv}$ and $\omega$ for the fine-grained soil-cement studied. Distinctive relations between $G_0/q_u$ and $\eta /C_{iv}$ of the silt-cement mixtures are presented for every moisture content considered, connecting stiffness and resistance.

A large-scale triaxial testing apparatus was upgraded by incorporating two pressure stabilization techniques so as to suppress the confining pressure fluctuation in dynamic experiments. Then it was used to study the residual strain behavior of a rockfill material subjected to different initial stress states and dynamic loading. It was found that the strain of the material under dynamic loading can be decomposed into a cyclic part and a residual part. In particular, the residual strains increase rapidly during the first few loading cycles. The strain accumulation rate, however, decreases gradually as the number of cycles increases. To simulate the increase of the residual (plastic) strains with the increasing number of loading cycles, a power function and an exponential function, taking into account the initial stress state, the cyclic shear strain amplitude, and the number of loading cycles, were proposed for the plastic shear strain and the plastic volumetric strain, respectively. The way to use the proposed model in predicting the earthquake-induced permanent deformation of rockfill dams was also explained briefly in the framework of the finite-element method.

The concrete permeability at low deformation of the chlorine ion is closely related to the porosity of concrete. Under stress, the porosity of concrete will change; at the same time, the chloride ion diffusion coefficient will also change. In this study, at the microscale, concrete was simplified as solid phase (zero porosity) and pore (the sum of various scales pores) of two phase composite materials. Based on the theory of elasticity, an analytical model was developed, and the quantitative relationship between the current porosity of concrete and the diffusion coefficient of the chloride ion, as well as the external equivalent stress, were evaluated. The primary parameters in the analytical model were the solid phase elastic moduli and the solid phase Poisson’s ratio, the initial porosity of the concrete and the external equivalent stress. The good agreement between the proposed model and the available test data illustrated the proposed model’s reliability and accuracy. The proposed model showed that the chloride diffusion coefficient or current porosity of concrete at low deformation levels decreases with the increase in compressive stress and increases with the increase in tensile stress. However, the initial porosity of concrete was still the primary factor influencing the chloride ion diffusion.

An indirect tensile test (IDT) is used to obtain material parameters of wearing surfaces such as used pavements of ordinary roads or bridges. In the general (classical) approach, tensile and compressive displacements in orthogonal directions of any test specimen are assumed to have similar creep compliances to simplify the calculations. Consequently, the Poisson’s ratio is obtained from the equation as a function of time. On the other hand, Poisson’s ratio estimated via the IDT test using this assumption is actually found not to be varying with time. In other words, it is independent of time. Thus, the classical approach assuming equal creep compliances under tensile and compressive stresses results in inaccurate Poisson’s ratio estimation, which obliges change in the calculation method. This study proposes a new method that assumes two different creep compliances under tensile and compressive stresses. It also presents the variation of stiffness moduli depending on time and the ratio between tensile and compressive creep compliances.

Few studies have been reported about the effect of high curing temperature on the engineering properties of lime/cement-treated marine soils as alternative materials in road construction. Laboratory tests, including the stress-strain relationship, unconfined compressive strength, tensile strength, deformation modulus, and failure strain, have been systematically investigated to fill this gap. Some useful conclusions were developed from the results and discussions. The strength and modulus increase with cement content, curing time, and curing temperature, leading to a decrease in failure strain. Experimental analysis shows an appropriate lime content of about 3% when using a single lime treatment. Further addition has no beneficial effect in producing an improved construction material. Cement seems to be more effective than lime in speeding up the mechanical performance of problematic soils under high curing temperatures. Different from the strength ratio and modulus ratio, relationships such as $\mathrm{UCS}\text{-}{ϵ}_f$, $\mathrm{UCS}\text{-}{R}_t$, and $\mathrm{UCS}\text{-}{E}_{50}$ are insignificantly affected by high curing temperatures at 40 and 60°C. The concept of material classification contributes to prove that the 60°C curing temperature can reach similar solidification effectiveness when combined with a certain quantity of granular materials. The formation of new cementitious phases detected through scanning electron microscope images is the main source in strength gain and microstructural change by the temperature-accelerated pozzolanic reaction and cement hydration. The current study provides a novel methodology to improve the in situ or laboratory solidification/stabilization technology.

Bitumen is an organic substance widely used in laying highway pavement because of factors like cost, availability, curing time, and environmental effects. Given improper design of pavements and selection of materials, asphalt mixtures may not perform well against certain phenomena like aging, rutting, stripping, fatigue, and thermal cracking. Therefore, in order to improve the performance of asphalt mixtures, it is necessary to add modifiers to bitumen, such as polymers, rubber, and clays. Among the modifiers, styrene butadiene rubber (SBR) is one of the most useful and effective materials for paving. In this study, the effects of SBR/nanoclay (NC) and SBR latex on the rheological properties of bitumen and the performance of asphalt mixtures were assessed. SBR/NC and SBR latex were made and mixed with bitumen. The morphologies of the samples were verified by fluorescent microscopy. The results indicate that SBR/NC-modified bitumen improved the dispersion in the asphalt matrix. The addition of modifiers increased the rotational viscosity, but all of the samples were workable during field placement and compaction of hot mix asphalt (HMA). High-temperature storage stability tests indicated that SBR/NC-modified bitumen is more stable than SBR-latex-modified bitumen. SBR/NC-modified bitumen showed a higher complex modulus $G^{*}$, a lower damping factor, totally improved viscoelastic properties, and superior high- temperature performance for both unaged and short-term aged asphalt. Indirect tensile fatigue test results showed that asphalt mixtures made from nanocomposite-modified bitumen have greater resistance to fatigue than SBR-latex-modified bitumens.

There has been inadequate investigation into the effect of steel reinforcement corrosion on the bond strength between steel rebar and structural self-consolidating lightweight concrete (SCLWC). This study investigates the physical and mechanical properties of developed SCLWC mixtures and their effectiveness in reinforcement corrosion prevention. Cylindrical pullout specimens made of SCLWC mixtures [incorporating 2–4% of metakolin (MK) and 10–12% of fly ash by weight of total cementitious materials] with a centrally embedded 20-mm-diameter reinforcing bar were used to study the effect of corrosive environment on bond behavior. A 5% NaCl solution was used as a corrosive environment and 0.05 A of direct current was applied for accelerated corrosion during the duration of testing. For noncorroded specimens, the highest bond strength was exhibited by specimen made of SCLWC with 0% MK. The specimens made of SCLWC with 4% MK showed highest bond strength (both normalized and unnormalized) when exposed to accelerated corrosion for a theoretical reinforcement mass loss of 2 and 5%. Besides, specimens with 4% MK showed highest resistance against chloride ion penetration.

Subgrade of roadways is subjected to repeated traffic loading at different loading intensities. The resilient modulus of subgrade is one of the important parameters for the design of pavements, including the estimation of permanent deformation (rutting) in the current Mechanistic-Empirical Pavement Design Guide (MEPDG). A significant portion of total rutting is often contributed by the subgrade, especially soft, fine-grained subgrade. Existing formulas for calculating rut depth of subgrade are only suitable for small deformation. Under certain conditions (e.g., low volume roads), large rut depth may be allowed. In addition, the resilient modulus and the accumulation of the permanent deformation of a fine-grained subgrade are still not well quantified under cyclic loading at different intensities. In this study, cyclic plate loading tests at different loading intensities were performed on six test sections of fine-grained subgrade constructed in a geotechnical testing box [$2\mathrm{m}\text{wide}\times 2.2\mathrm{m}\text{long}\times 2\mathrm{m}\text{high}$]. The California Bearing Ratios (CBRs) of the test sections ranged from 2.9 to 15.8%. The intensities of loading applied on a steel plate 305 mm in diameter increased from 5 to 70 kN, in load increments of 5 kN. In these tests, deformations and vertical/horizontal stresses were measured at varying distances from the center of the loading plate. For each test section, dynamic cone penetrometer (DCP) tests and light weight deflectometer (LWD) tests were performed and a correlation between the CBR and dynamic modulus obtained from LWD tests was developed. Based on the measured surface resilient (elastic or recoverable) deformations, the resilient moduli of test sections at different loading intensities were back-calculated. The MEPDG soil damage model was modified to consider the influences of subgrade stiffness and bearing capacity. The modified MEPDG model was verified by two test sections with the base course over the subgrade, and the permanent deformations predicted by the modified model compared well with the measured results.

Carbonated reactive magnesia (MgO)-admixed soil is employed for stabilizing soft soil through absorbing gaseous ${\mathrm{CO}}_2$, which is an innovative and sustainable technique recently developed in the realm of ground improvement. With this in view, a systematic study that targets the influence of the MgO activity index ($c_A$) on mechanical and microstructural characteristics of carbonated silty soil with different ratios of initial water content to MgO content (represented as $w_0/c$) is initiated in this paper. In this context, the mechanical properties are investigated through unconfined compression tests, and the microstructural properties are obtained from X-ray diffraction, scanning electron microscopy, thermogravimetry, and mercury intrusion porosimetry analyses. The results demonstrate that $c_A$ and $w_0/c$ are the two crucial factors controlling the mechanical and microstructural characteristics of carbonated MgO-admixed soils. A simplified equation with combination of $c_A$ and $w_0/c$ is proposed for accurately predicting the unconfined compressive strength of carbonated MgO-admixed soils. The analyses of microstructural characteristics indicate that dypingite or hydromagnesite and plentiful crystalline nesquehonite play an important role in reducing the pore volume, and the latter is the primary micromechanistic reason for the strength gain of the carbonated MgO-admixed soils.

High volumes of construction and demolition waste (CDW) are continuously produced worldwide. The European Commission aims to increase the recycling of nonhazardous CDW to a minimum of 70% in weight terms by 2020. Hence, there is increasing pressure on researchers to focus on the valorization of these alternative materials for use in the world of construction alongside traditional materials. CDW contains materials from excavation and/or demolition and are typically heterogeneous in terms of composition, grain size, and toughness; furthermore, some particles are more sensitive to degradation processes than others. One solution for an increase in durability while maintaining sufficient strength levels is chemical stabilization with cementitious binders. The paper illustrates the results of a laboratory investigation into the properties of CDW when subject to stabilization with cement kiln dust (CKD). Mixtures of CDW stabilized with ordinary portland cement (OPC) were prepared for comparison purposes. The results obtained with CKD are encouraging because it increases the strength and stiffness of CDW, thus leading to a material completely made up of recycled wastes and by-products usable in the formation of pavement subbases and subgrades. As regards the curing time, all mixtures saw a significant increase in their mechanical parameters when passing from 7–28 days to 365 days of curing.

Ionic diffusivity is of critical importance to the service life of cementitious composites. In this paper, ionic diffusivity of cement paste is modeled with the solid mass fractal model and the lattice Boltzmann method. In particular, the solid mass fractal model is proposed and applied to build up pore structure in conjunction with the porosimetric test. Thereafter, the lattice Boltzmann method is applied to model the associated ionic diffusivity with respect to the law of ionic diffusion for both saturated and unsaturated cement pastes. In addition, for the sake of validation, the results of the present modeling are compared with those obtained from literature and experiment.

The present experimental study investigated the behavior of hot-mix asphalt (HMA) under repetitive creep and recovery loading. Cylindrical samples of HMA were subjected to trapezoidal and haversine loading followed by unloading. Different amounts of unloading (stress reduction) and relaxation periods (rest periods in complete unloading) were tested. The measured vertical deformation was decomposed into viscoelastic and viscoplastic components. It was observed for cyclic loading that an increase in unloading and/or relaxation period increased the recovery of viscoelastic strain, which in turn increased the accumulated viscoplastic strain in subsequent loading cycles. It appears that repetitive creep and recovery loading caused slight reorientation of the aggregates and changes in the microstructure. This led to relaxation of stress hardening of the materials and resulted in higher viscoplastic strain in subsequent cycles.

This paper presents an integrated computational-experimental approach for evaluating recovered fracture strength after light-healing of graphite-modified asphalt mixture beams. The cyclic fracture and light-healing tests were conducted to measure the recovered fracture strength of the asphalt mixture samples as reported in another paper. A two-dimensional (2D) multiphase bilinear cohesive zone model (CZM) was employed to predict the original and recovered fracture strength of the asphalt mixture samples. The digital image correlation (DIC) method was used to analyze the crack displacement variation of the samples during the fracture and light-healing processes. The relative strain ratio from DIC, originally measured fracture energy, and peak separation stress were combined to calibrate the recovered fracture energy of beams after light-healing processes. Two input parameters, calibrated fracture energy and peak separation stress, were used to simulate the sample fracture behavior and predict the recovered fracture strength. The relative difference of the fracture strength between the simulation and experiments was calculated to validate the 2D bilinear CZM simulation. The results indicated that the CZM with calibrated fracture energy and measured peak stress is capable of predicting the recovered fracture strength after fracture and light-healing cycles.

In recent times microbially induced calcite precipitation (MICP) has emerged in the cement and concrete industry as a pioneering approach to enhance concrete properties. This research was carried out with the intention to study the changed characteristics of masonry concrete, casted using brick aggregates modified by MICP. Biodeposition of ${\mathrm{CaCO}}_3$ on treated brick surfaces were detected via optical microscopy, scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and energy-dispersive spectroscopy (EDS) analysis and analyzed through quantification of calcium carbonate. Absorption tests and mercury porosimetry tests were carried out to determine the changed brick characteristics. Finally, durability parameters of modified brick aggregate-concrete were determined through sorptivity test, rapid migration test (RMT), and compressive strength test. Experiments conducted on brick aggregates reveal that MICP methods were successfully executed leading to ${\mathrm{CaCO}}_3$ precipitation. Furthermore, the modified-brick-aggregate-concrete exhibited increased compressive strength and significantly decreased permeability when compared to control specimens with untreated brick aggregate.

Virgin aggregate is heated and dried in a drum dryer and uses this heated mass to heat and dry reclaimed asphalt pavement (RAP) and/or recycled asphalt shingles (RAS) materials in a drum mixer before blending with virgin asphalt binder. However, often the virgin aggregate temperature inside the dryer is unknown since many dryers do not have a temperature-measuring unit but the mixer has. Up to this end, thermodynamics and heat transfer principles are applied to predict virgin aggregate temperatures necessary to dry and heat RAP/RAS with varying moisture content and for various hot-mix asphalt (HMA) mix proportions. Among the many results, it is found that for a HMA mix consisting of 50% virgin aggregate with 3% moisture content and 50% RAP with 5% moisture content, the temperature required to raise the virgin aggregate temperature is 608°C to dry and heat virgin aggregate and RAP. For verification purposes, the virgin aggregate temperature is recorded at a drum plant facility, and thermodynamics and heat transfer principles are used to predict the virgin aggregate temperatures. It has been observed that for the HMA mix, the temperature predicted for larger-size virgin aggregate shows good agreement with the recorded value.

Geopolymer has earned a significant position in the construction industry. A number of researchers have attempted to use it as a concrete-repairing material. To enrich the literature with results on geopolymer as a concrete-repairing material, the present study reports experimental works performed on geopolymer mortars prepared from ultrafine ground granulated blast-furnace slag. Geopolymer mortars were prepared with alkali activators composed of (1) sodium silicate and sodium hydroxide, and (2) only a sodium hydroxide solution, and tested to study the setting time, workability, and strength-gain behavior. Furthermore, to the sodium hydroxide-activated mortars, certain admixtures such as fly ash and superplasticizer were added in various quantities to study their effect on the mentioned properties. The effect of alkali activator concentration and time of addition of superplasticizer has also been observed through the laboratory experiments. A total of 504 cube samples for a total of 28 different mortar mixes were prepared and tested for observing strength-gain behavior. Results indicated that sodium silicate-free mortars were better than sodium silicate-containing ones in terms of setting, workability, and strength-gain performance. Addition of an admixture altered the setting time and workability of the mixes. The early-strength-gain property of the mixes also altered due to such admixtures.

Lateral pressure exerted on vertical formwork by fresh self-consolidating concrete (SCC) controls its design. Several factors, including material properties, placement conditions, and formwork characteristics, can affect formwork pressure. This paper presents the influence of formwork width (0.20–1.0 m), shape (circular versus square), and surface material (PVC, plywood, steel, and polyester filter membrane) of formwork on lateral pressure characteristics. The diameter of the pressure sensor used to evaluate lateral pressure characteristics is also investigated. The results showed that the increase in formwork width can increase the initial lateral pressure and delay the time needed for the formwork removal. Correction factors accounting for the changes in the formwork width on the initial pressure and pressure decay were developed. The formwork surface materials did show significant effect on initial formwork pressure, and different pressure decay responses were observed for each formwork material. The longest time for pressure cancellation was obtained for the steel formwork, and the shortest one for the polyester filter membrane.

An acoustic-emission approach to evaluate the low-temperature cracking performance of asphalt binders is presented. The acoustic activity of a thin film of asphalt binder bonded to a granite substrate is monitored while the layer is exposed to decreasing temperatures from around 20°C to approximately $-50°\mathrm{C}$. Results of eight different asphalt binders at three different aging levels, i.e., unaged (TANK), short-term aged (RTFO), and long-term aged (PAV), are presented. The acoustic emission (AE) embrittlement temperatures are found to be sensitive to binder type as well as binder aging level. Results show that for most binders, their AE-based embrittlement temperature is a few degrees lower than their bending beam rheometer (BBR) critical cracking temperatures.

In recent years, many studies have dealt with the inadequacy of the current Superpave performance grading (PG) specification for accurately capturing the performance properties of modified binders. An alternative binder testing mode that has gained much attention in recent years is the repeated creep and recovery (RCR) test, and more specifically, the multiple stress creep and recovery (MSCR) test. As with any new test procedure, a number of concerns and questions remain with regards to interpretation of results in terms of performance and sufficiency of the number of cycles and stress levels used, as well as representative temperature and stress levels to be used. This paper investigates the aforementioned issues using a set of modified and unmodified binders. The results show that the standard 10 cycles per stress level are not sufficient to reach a stable steady-state creep behavior for modified binders, thus the addition of 20 conditioning cycles are recommended, for a total of 30 cycles for each stress level. It is also shown that using the last five cycles to determine an average $J_{nr}$ value is a better choice for reporting and analysis due to reaching a more stable and consistent state of creep. Furthermore, the current stress levels’ use of 0.10 and 3.20 kPa are deemed insufficient for accurate representation of binder stress state in the pavement, thus a higher stress level step is recommended for addition to the test procedure.

This study investigates the crack propagation behavior of asphalt materials through the use of damage models using the principles of the disturbed state concept (DSC). Traction–separation crack response, crack initiation, and evolution behavior are investigated by modeling pavement systems consisting of a hot mix asphalt (HMA) overlay on an existing HMA layer and subjected to wheel loading. Pre-existing cracks located within the existing asphalt material are also considered. The extended finite-element method (XFEM) was employed to model mesh-independent cracking. The finite-element model was validated by comparing the results to indirect tensile and direct tensile laboratory testing on asphalt samples. The validated model was then used to examine crack propagation in the pavement system with and without pre-existing cracks.

Production and use of sustainable cold asphalt emulsion mixtures (CAEMs) that are comparable to traditional hot mixtures and relevant for roads and highway construction might achieve several benefits such as reducing energy consumption, ${\mathrm{CO}}_{2\mathrm{e}}$ emissions, and total expenses. Furthermore, some of by-products and waste materials could be incorporated in these mixtures to enhance their properties. The purpose of this investigation is to produce CAEM incorporated by producing material(s) with mechanical properties and water sensitivity comparable to conventional hot asphalt mixtures. The mechanical properties have been evaluated by conducting indirect tensile stiffness modulus (ITSM) test and uniaxial compressive cyclic tests (UCCTs), while water sensitivity was evaluated by determining the indirect tensile strength ratio (ITSR). A waste fly ash (WFA) has been incorporated instead of mineral filler with different percentages (0–6% by weight of aggregate), while ground-granulated blast-furnace slag (GGBS) was added with dosages ranging from 0–3% by total mass of aggregate to produce the novel CAEMs. The results revealed a considerable enhancement in the performance of the new CAEM mixtures as a result of using WFA and GGBS in comparison with the conventional hot asphalt mixture properties.

The actual concrete compressive strength (MPa) for given mixture compositions for a specific age (days) is completely unknown. Based on an appropriate probabilistic model, it is only possible to identify the optimal level combinations of the mixture components to obtain the maximum concrete strength. In quality engineering, the most important problem is to predict the operating conditions that optimize concrete compressive strength (CCS) and simultaneously minimize the process variability. The considered CCS is a mixture of seven ingredients: cement, blast-furnace slag, fly ash, water, superplasticizer, coarse aggregate, and fine aggregate. It is found that the positive response variable CCS distribution is gamma and its variance is nonconstant. Thus, joint generalized linear models analysis is used to derive the joint mean and variance models. The present analysis has derived the following: (1) age, and all the marginal effects of the mixture components except superplasticizer, are significant either in the lognormal or the gamma mean model, (2) one third-order and six second-order interaction effects are significant in the final selected gamma mean model, (3) all the marginal effects of the mixture components are significant in both the variance models, and (4) six second-order interaction effects are significant in the final selected gamma variance model. A nonlinear stochastic third (second)-order mean (variance) model of CCS has been derived for seven ingredients along with the age. Effects of the ingredients along with the age on CCS have been derived from the presented derived mean and variance models.

Methods used for laboratory sample preparation should be able to produce uniform and highly repeatable sand beds of required density and to simulate field conditions. Air pluviation is a widely used method to prepare cohesionless soil samples in the laboratory. In the present study, two currently used air pluviation setups, viz, stationary/portable traveling pluviator (PTP) and movable/mechanized traveling pluviator (MTP), are investigated in terms of their ability to prepare uniform and repeatable sand beds of a wide range of relative densities. The PTP and MTP pluviation setups mainly comprise hopper, orifice, flexible hose, and rigid tube. Chain pulley and rail track are the additional features of MTP, which allow the hopper to travel smoothly in one direction. Pluviation studies are performed by using Indian standard sand (Grade II), and a California bearing ratio (CBR) mold is used to evaluate relative density (RD) and deposition intensity (DI) of samples. The effect of height of fall (HF), DI, and number of diffuser sieves on the RD of the sand sample is studied for both the PTP and MTP pluviation setups. A model tank is used to verify the uniformity of the sand samples with the help of miniature cone-penetrations tests. The test results reveal that a wide range of RD with uniform and repeatable sand samples can be prepared by using MTP compared with PTP.