Journal of Materials in Civil Engineering

Research using marble powder as a partial replacement of cement in concrete has gained a lot of attention recently. In this paper, the effect of dried marble powder on particle packing of concrete has been demonstrated. Experimental investigations have been conducted on the effect of marble powder on hydration reaction, strength activity index, and possible reasons for the gain in strength. In addition, statistical methods were used to develop two mathematical models for marble powder incorporated in concrete using experimental values. In the first model, the ratios of 28-day compressive strength between concrete with cement partially replaced by marble powder and control concrete have been related to marble powder replacement percentage. In the second model proposed, modified and simplified relationships for the water-cement law when cement is partially replaced by marble powder have been provided. The first model was validated for both standard cubes and cylinders used for testing by researchers and the predictions showed only 7.15% error as compared with the experimental values. The second model might serve as a useful tool for mix proportioning of concrete mixes incorporating marble powder in concrete. Finally, based on a review of the literature and experimental results, a set of guidelines has been proposed for the use of marble powder as a partial replacement of cement in concrete.

This paper investigates the effect of reinforcement forms on the interface shear strength of geosynthetic-reinforced granular soil by conducting a set of large-scale direct shear tests. Three sands of different size (fine, medium, and coarse) and fine gravel of particle size between 0.075 and 10 mm were used for the study. Planar and three-dimensional (3D) geogrids of triangular and rectangular forms were adopted as the reinforcing material. The tests were performed at three different normal stresses of 100, 150, and 200 kPa. The interface shear-strength parameters of different granular soil–reinforcement interfaces were quantified in terms of interface friction angle, apparent cohesion, and interface shear-strength coefficient. The effect of position of the 3D geogrid in the upper or lower shear box on the interface shear behavior was also studied. The tests results show that 3D geogrid–reinforced soil provides higher interface shear-strength coefficients compared with unreinforced and planar geogrid–reinforced soil. The highest interface shear-strength coefficient was observed with 3D geogrid–reinforced medium sand (1.25), which shows minimum unreinforced shear strength. It was also observed that the interface shear-strength coefficients were higher for 3D geogrids with rectangular form compared with the triangular form. The results of the present investigation encourage the usability of 3D geogrids in reinforced soil structures.

The subject of this work is the low-permeability cementitious paste produced by a novel composite binder due to the selection of the optimal component ratio and use of advanced manufacturing technology. The binder is produced through joint grinding of portland cement, fly ash, and limestone together with superplasticizer using a vario-planetary mill. Grinding of active mineral supplements allows crystallization of ash particles as a result of the binding of $\mathrm{Ca}{(\mathrm{OH})}_2$ during the hardening of alite, which intensifies the clinker mineral hydration process; the presence of fine-grained limestone also leads to hydrocarboaluminate calcium formation. The highest strength was measured when 45% by weight of portland cement is replaced with industrial waste. This higher strength of milled portland cement is due to the increased formation of so-called needlelike and stemlike crystals. In general, the reduction, by more than twice, in the capillary porosity of compositions modified by technogenic waste should be noted for all specimens compared with the reference specimen.

Graphene and graphene oxide (GO) sheets have great potential to improve the properties of traditional cement-based building materials. This research studied the effects of graphene and GO sheets on the flexural and compressive strength of cement paste. After dispersion into water with an effective surfactant, graphene and GO sheets can be stored stably for several days. As the proportion of graphene and GO sheets increased from 0% to 0.1% by weight, the mechanical properties of the nanocomposites were improved significantly. With the addition of 0.05% by weight graphene sheets, the flexural strength of the samples increased by 38% and 23% at 7 and 28 days, respectively. The compressive strength of specimens was also improved by the addition of graphene sheets. However, the results showed that high content of GO sheets has an adverse impact on the mechanical properties. Scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) analysis showed that the addition of graphene sheets improved pore-diameter distribution and formed a compact microstructure of cement paste.

This study focused on the optimization of concrete mixture and geometric design parameters for a drilled shaft to effectively reduce the potential degradation of mass concrete. At concrete’s early hardening stage, the heat of hydration plays a pivotal role that affects the integrity of mass concrete. The Florida Department of Transportation (FDOT) currently designates concrete drilled shafts with a minimum diameter of 1.8 m as mass concrete due to a great concern about high temperature development. In this study, a validated thermal finite-element (FE) model for a drilled shaft with a diameter of 1.8 m was developed for a parametric analysis to determine the effects of concrete property, surrounding soil condition, geometric design, and pipe cooling on temperature development. The results indicated that the use of supplementary cementitious material (SCM) significantly reduced the temperature development in a drilled shaft. The temperature development increased as the placement temperature and volume:surface area ($V:A$) ratio increased. In particular, the use of a centroid void shaft and a pipe cooling system significantly decreased the maximum temperature and temperature differential, and could be a viable solution to effectively mitigate the temperature development, preventing potential disintegration due to the effects of delayed ettringite formation, strength reduction, or thermal cracking.

This paper investigates the effects of rheological performance, antifoaming admixtures (AFA 1 and AFA 2), and mixing procedure on air bubbles and the mechanical strength of ultra-high-performance concrete (UHPC). Thirty-eight mixtures were prepared by varying the water-to-binder ratio from 0.21 to 0.27, the dosage of superplasticizer (SP) from 2.5% to 4.0%, cationic polyacrylamide from 0‰ to 3.0‰, AFAs from 0.5‰ to 4.0‰, and mixing duration from 4 to 12 min at two mixing speeds. The air content in a fresh mixture and air bubble parameters in hardened samples were measured using a pressure gauge method and digital image analysis, respectively. Compressive and flexural strengths were tested for all the mixtures after 7 and 28 days of standard curing. Results show that a lower yield stress and/or plastic viscosity and higher incorporation of AFAs reduce the content of air bubbles in hardened UHPC. Higher mixing speed is more beneficial for reducing the content and average diameter of entrapped air bubbles. The 28-day compressive strength linearly increases with the decreasing content and average diameter of air bubbles. Air bubbles with diameters larger than 1 mm have worse effects on strength of UHPC than the smaller bubbles. Therefore, mechanical strength of UHPC can be improved by controlling the content and size of air bubbles through regulating rheological properties, incorporating anti-foaming admixture and optimizing mixing procedure.

This paper presents the investigation of the strength characteristics and microstructural analysis of cement composite mortar developed using nontraditional cement replacement materials. Three types of materials, namely palm oil fuel ash (POFA), treated palm oil fuel ash (TPOFA), and bottom ash (BA) were used as partial cement replacement materials at replacement levels of 0%, 10%, 20%, and 30% by weight. The water to binder ratio (w/b) of 0.32 was used for all mortars. The chemical composition and morphology of binder materials were examined by X-ray florescence (XRF) and scanning electron microscope (SEM) techniques. The fresh and hardened properties of mortar were determined in accordance with ASTM standards and the microstructure of mortar was investigated using X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). The results showed pozzolanic activity through formation of C-S-H and CH as confirmed by XRD, TGA, and FTIR. Partial replacement of cement with 10%, 20%, and 30% of TPOFA produced higher compressive strengths of 101.4, 88.4, and 83.6 MPa, respectively, which is slightly closer to 110.0 MPa obtained for control specimen at 90 days. Moreover, higher strength activity index for TPOFA and BA specimens showed better pozzolanic activity as compared to POFA-based mortar. Overall, the use of 10% of POFA, TPOFA, and BA is recommended as a cement replacement in the development of high-strength mortar of strength range of 60 to 100 MPa.

Studies on shredded waste tires mixed with sand for fill applications are well documented. In this study, a new composite material from mixture of shredded tires and fly ash as fill material is explored. Shredded waste tires with nominal size equal to 9.5 mm (granulated rubber), and fly ash generated from two thermal power plants are used in the study. The composite material is obtained by mixing different proportions of granulated rubber and fly ash. Granulated rubber content equal to 0%, 10%, 30%, and 60% (by weight of fly ash) in the mixture are tested. Compaction characteristics, optimum mixing ratio, and shear strength properties of the mixtures are determined. The maximum dry unit weight and the optimum water content values ranged between 15%–22.5% and $12.6–14.6\mathrm{kN}/{\mathrm{m}}^3$, and 10%–27% and $10.5–11.6\mathrm{kN}/{\mathrm{m}}^3$ for mixtures prepared with fly ashes from two sources. Large-size direct shear apparatus is used to obtain the angle of shearing resistance and apparent cohesion of mixtures at both peak state and at near end-of-test. The shear strength of fly ash and granulated rubber mixture is found to be higher than that of fly ash alone or granulated rubber alone, and the maximum shear strength of the composite material is observed for granulated rubber contents equal to about 60% (by weight of fly ash). The peak shear strength parameters of mixtures, apparent cohesion and friction angle, are found to be in the range 14.9–46.0 kPa and 37.5°–50.1°, respectively. Based on minimum void ratio, optimum mix proportions of granulated rubber and fly ash from two sources ranges between 54%–100% and 81%–185% (by weight of fly ash). Based on shear strength testing, fly ash-granulated rubber mixtures are found to perform better than sand-granulated rubber mixtures.

Hydrated lime has been recognized as an effective additive used to improve asphalt concrete properties in pavement applications. However, further work is still needed to quantify the effect of hydrated lime on asphaltic concrete performance under varied weather, temperature, and environmental conditions and in the application of different pavement courses. A research project was conducted using hydrated lime to modify the asphalt concretes used for the applications of wearing (surface), leveling (binder), and base courses. A previous publication reported the experimental study on the resistance to Marshall stability and the volumetric properties, the resilient modulus, and permanent deformation at three different weather temperatures. This paper reports the second phase of the experimental study for material durability, which investigated the effect of hydrated lime content on moisture susceptibility when exposed to a freeze-thaw cycle, and fatigue life. The experimental results showed an improvement in the durability of the modified asphalt concrete mixtures. Optimum hydrated lime contents for different course applications are suggested based on the series experimental studies. Finally, the advantage of using the optimum mixtures for a pavement application is demonstrated.

The corrosion risk in reinforced mortar slabs containing untreated sugarcane bagasse ash (UtSCBA) (0%, 10%, and 20% replacement of cement) was analyzed for 75 months. The mortars were prepared with a constant 0.63 water/cementitious-materials ratio. Cylinders and reinforced slabs were cast with the mortars. Two galvanized wire meshes were used as reinforcement for the slabs. Curing regimes of 0, 7, and 28 days were applied to the samples. The cylinders were used to obtain the compressive strength (CS) and the chloride diffusion coefficient ($D_{eff}$) of the mortars. To evaluate the corrosion risk, the slabs were exposed to wet-dry cycles of 12 h each in a 3% NaCl solution. Corrosion potential measurements and linear polarization resistance tests were taken every 28 days for that purpose. It was found that the addition of 10% and 20% UtSCBA reduces the workability of the mortar binders and leads to a slight decrease in the CS of hardened mortars. However, it significantly reduced the $D_{eff}$ of the mortars by 50% and 65% ($p\ll 0.05$), respectively, and also decreased the corrosion risk of mortar slabs over time.

The aim of this paper is to implement a numerical model to reproduce the nonlinear behavior of cob walls under shear loading. Axial compression, pull-off, and diagonal compression tests were carried out to derive the mechanical parameters. In addition, the stress-strain relationships, the nonlinear behavior, and the failure modes were defined. The experimental results were then used to calibrate a finite-element model. The material behavior was simulated through a macromodeling approach adopting the total strain rotating crack model. A sensitivity analysis was conducted to assess the effects of varying the parameters with higher uncertainty on the structural behavior. The numerical model achieved good correspondence with the experimental results in terms of simulation of the shear stress–shear strain relationship and of damage pattern.

For comprehensive utilization of the coal gangue from different locations, coal gangues were calcined at temperatures of 800°C, 900°C, and 1,000°C for 2 h, respectively, and then blended in cement with a replacement level of 10%, 20%, 30%, and 40% by weight to fabricate the blended cement mortars. By means of Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), and an ion solubility test, the thermal-activation mechanism and pozzolanic activity evaluation for coal gangue was investigated, and the effect of coal gangue on mechanical properties and the hydration process of cement mixture was also studied. Results show that the optimum thermal-activation temperature of coal gangue is 800°C: the coal gangues in Yangquan, Huozhou, and Xinzhi, China, had higher activity and the replacement level of coal gangue in the cement can reach 40% by weight, but the coal gangues in Yanzhou, Zhengzhou, and Qitaihe, China, showed lower activity. The replacement level of coal gangue in the cement should not exceed 20% by weight. The active ${\mathrm{SiO}}_2$ and ${\mathrm{Al}}_2{\mathrm{O}}_3$ in the thermal-activated coal gangue are able to react with the $\mathrm{Ca}(\mathrm{OH}{)}_2$, which was produced by cement hydration, and form hydrated calcium silicate and hydrated calcium aluminate gel to enhance the compressive strength of cement.

Recently, various types of additives are being used to enhance the properties of bitumen. Until now, few researchers have handled the utilization of different additives in the same binder. In this study, styrene-butadiene-styrene (SBS) and Evotherm were used both separately and in the same blend. Dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests were applied to SBS and Evotherm modified binders. SBS and Evotherm were added to pure bitumen in three different ratios. Sixteen different combinations were produced using the two additives, and a pure binder in the same binder was evaluated in the DSR test. Eight different combinations were evaluated in the BBR test. The conclusion reached was that the maximum usage of Evotherm (0.9%) induces a 20% reduction in the rutting parameter of both the 5% and 6% SBS modified binders. The 0.5% Evotherm with 4% and 5% SBS modification does not have an adverse effect on rutting performance. Evotherm modification could prevent the stiffness increment that originates from using the SBS additive, especially at high content. Using 0.7% Evotherm with 4% SBS can acquire the pure binder’s low temperature performance.

In order to evaluate the influence of filler type on the moisture susceptibility of asphalt mixtures, this study examined the thermodynamic properties of mastic and the mechanical properties of hot-mix asphalt subjected to multiple freeze-thaw cycles. Furthermore, the potential of using waste concrete aggregates as filler material was particularly evaluated using the moisture damage properties of asphalt mixtures. To fulfill these objectives, recycled concrete aggregates, limestone filler, and portland cement were used as filler materials in asphalt mixtures and siliceous stone powder was used as filler in control samples. The indirect tensile strength and resilient modulus tests were performed as commonly used experiments to assess the moisture sensitivity of asphalt mixtures. Furthermore, the surface free-energy components of mastics as well as the cohesion and adhesion of the mixtures were determined. The results of mechanical and thermodynamic experiments suggest that asphalt mixtures containing the portland cement filler outperform those containing other types of filler at all freeze-thaw cycles in terms of moisture susceptibility. However, recycled concrete aggregates are a sustainable alternative for the aggregate filler and, based on results, they can improve the moisture resistance of asphalt mixtures, particularly at increased freeze-thaw cycles.

Limited research has been reported on strength improvement of biocemented soils in relation to crystal patterns of microbially induced calcite (${\mathrm{CaCO}}_3$) precipitation (MICP). In this study, sand samples were treated under the coeffect of different bacterial culture (BC) and cementation solution (CS) concentrations to evaluate the optimum BC and CS combination that yields the highest soil strength. It was found that for lower CS conditions (0.25 M), higher BC produced stronger samples, whereas for higher CS conditions (0.5 M or 1 M), lower BC was more dominant in improving the soil strength. This can be attributed to the effectively precipitated ${\mathrm{CaCO}}_3$ crystals, which were in rhombohedral shape and large size and were concentrated at the soil pore throat rather than deposited on the individual sand grain surface. This finding was confirmed with the scanning electron microscopy (SEM) analysis. The strength and permeability of the optimized biocemented samples were also compared with sand samples treated with ordinary portland cement (OPC). The optimized biocemented sand provided higher strength and permeability than those obtained from the samples treated with similar content of OPC at a curing period of 28 days.

Stone matrix asphalt (SMA) is a gap-graded mixture that consists of two parts, a high concentration coarse aggregate skeleton and a high binder content mortar. The coarse aggregate skeleton provides the mixture with stone-on-stone contact, giving it strength, while the high binder content mortar adds durability. The mortar is typically composed of fine aggregate, mineral filler, asphalt binder, and a stabilizing additive. A stabilizing additive such as natural fibers, mineral fibers, or polymers is added to SMA mixtures to prevent draindown. In addition, it has the potential of reinforcing and improving the tensile strength and cohesion of SMA mixtures. In this study, banana fiber (BF) and pelletized fiber (VP) are used as stabilizing additives to prepare SMA mixtures with conventional viscosity-graded (VG) 30 bitumen. Mixtures were prepared with different levels BF and VP content, and another mixture without any stabilizers was also prepared using polymer-modified bitumen (PMB). Superpave mix design, draindown, fatigue, rutting, workability, and moisture-induced damage properties were evaluated. Results indicated that addition of natural and pelletized fiber controls binder draindown and improves resistance to rutting, fatigue, and moisture-induced damage of SMA mixture. Further, polymer-modified SMA mixtures take less energy for densification compared to SMA mixtures with natural and pelletized fiber. Results also showed that even though polymer-modified SMA mixtures performed better, SMA mixtures with pelletized fiber provided comparable results.

The use of high-performance steel (HPS) in new bridge construction continues to increase as engineers and owners recognize the potential for cost savings and performance benefits. One intended advantage of HPS is the increase in fracture toughness when compared with conventional bridge steel. However, limited research has characterized HPS fracture toughness, and current material specifications provide no opportunity for owners to benefit from the improved performance resulting from increased fracture toughness. This paper presents the fracture toughness testing and analysis of eight A709 HPS 485W (70W) and 690W (100W) steel plates. The resulting fracture toughness values are used to determine tolerable flaw sizes for a representative girder flange. A comparison is made with tolerable flaw sizes based on toughness estimations from the current fracture critical material toughness specification. The results indicate that HPS is exhibiting toughness far in excess of current specification requirements.

Many tests and methods can be used to assess or verify the self-healing mechanisms of cement-based materials. This study, which is part of wider project, deals with the development and application of a test method for studying the self-healing ability of cementitious composites. The principle of this method lies in the bonding capacity of self-healing products under direct tension loads. A specially designed cylinder specimen was split after 7 days of water curing, and then the two parts of the split specimen were carefully put together immediately. A connector apparatus was designed to keep the surface of each part connected to each other with equal pressure for the “healing” process in water. After 30 days, the specimens were tested by a special direct tension test method to evaluate the bond loads. In addition, the crack-closing ratios were monitored on precracked disc-shaped specimens. The bond loads of 7 different ultra-high-performance concrete (UHPC) mixtures were compared with the crack-closing ratios. The healing process in the novel test, which simulated the self-healing of very narrow cracks, was observed to differ from the crack-closing test method. Considerable bond loads were obtained in both fly ash (308 N) and ground granulated blast furnace slag (GGBFS) (210 N) bearing mixtures. Additionally, the maximum crack-closing ratio (100%) was observed in the GGBFS bearing mixture.

Microstructural changes in concrete, mortar, and cementitious composite material were investigated to determine the efficacy of these materials subjected to shock loading. An experimental methodology with the ability to generate reproducible shock waves of specified blast pressure and decay time was used to perform repeatable experiments in the range of trinitrotoluene (TNT) explosion that is unsafe for concrete columns as specified in the FEMA (Federal Emergency Management Agency) guidelines (38 kg TNT at 3.7 m). The changes in the pore volume fraction of the samples before and after shock loading were used to determine the efficacy of the materials subjected to shock loading. The study reveals that even though percentage increase in pore volume fraction before and after shock loading is highest for cementitious materials, its absolute value is low compared to that of control samples, thereby justifying the better performance of cementitious composite materials. Moreover, the size of the pores is also observed to be lower for cementitious composite samples compared to those of the and concrete samples after shock loading in comparison to the control materials in the study. The reason for the better performance of cementitious composite materials can be attributed to an increase in tensile ductility of the sample as a result of fiber addition. Apart from development of a new cementitious material for blast load mitigation, the study also demonstrates the need to consider pore size distribution in equations relating pore volume fraction to strength.

In this study, the effect of thermal shock (TS) on the mechanical properties of granite is investigated. Two schemes are performed to provide different cooling rates for the TS processes. Decreasing trend of dry density and P-wave velocity with ascending TS temperatures are observed. The porosity has an increasing trend with ascending TS temperatures. The effects of TS on the mechanical responses are investigated through Brazilian tests on the granite specimens of the cracked straight through Brazilian disc (CSTBD) under Mode I and Mode II loading. Mode I and Mode II fracture toughness values are obtained according to the mechanical tests, and a power relation is proposed to fit the fracture toughness values with respect to TS temperatures. Scanning electron microscope (SEM) is adopted to observe the fracture surfaces of the TS-treated specimens after the tests. Distinct features such as intergranular fracture are identified on the fracture surface of a water-cooled specimen, which indicates material deterioration to a greater extent as compared with that of an air-cooled specimen.

This paper reports the results of 120 low-cycle fatigue tests on steel reinforcing bars with varying slenderness ratios at varying strain amplitudes. The failure modes of the fractured bars were investigated through analysis of the fracture mechanisms of bars. The results of experimental testing were used to update empirical models of low-cycle fatigue life for such bars. The newly improved empirical models were then incorporated into a recently developed constitutive material model that accounts for bar buckling and fatigue. The experimental results show that the size effect is significant for short steel reinforcing bars where there is no buckling. The results also show that as the slenderness ratio of the steel reinforcing bars increases, the influence of the bar diameter on low-cycle fatigue reduces.