Journal of Materials in Civil Engineering

This study investigated the topography of plain concrete during freeze-thaw exposure and following abrasive blasting. The independent variables included the water-cementitious material ratio ($\mathrm{w}/\mathrm{cm}$) (0.42, 0.50, or 0.56); the number of freeze-thaw cycles (100, 200, or 300); and the blasting method (dry ice or sand). Using the three-dimensional (3D) surface roughness as the response parameter, the analysis of variance (ANOVA) results indicated that the number of freeze-thaw cycles is most influential in governing the measured roughness due to both freezing and thawing and abrasive blasting. The statistical data indicate that the roughnesses created by the blasting methods are not significantly different, which suggests that both dry ice and sand produced equivalent surface topography. However, qualitative examinations revealed that sand blasting generated a relatively uniform surface, whereas dry ice blasting created localized damage in the form of pitting. This effect may stem from differences in the flow behavior and size of the particles prior to impact with the substrate.

The current study focuses on options to improve vehicle energy efficiency by reducing rolling resistance on Dutch national highways. Different studies of pavement materials have been evaluated, and models have been compared to experimental data to review rolling resistance indicators. The study shows that texture parameters MPD (mean profile depth) and RMS (root mean square) are relevant indicators for rolling resistance, whereas the effect of road roughness (IRI) is found to be larger than indicated in the evaluated models. The effects of other wavelength regions, texture orientation, and road wear need further investigation. The rolling resistance assessment shows that single-layer porous asphalt concrete (PAC) with aggregate size $6/16$ (which is most currently used on Dutch highways) has rolling resistance levels that are 8–10% higher than the levels of double-layer porous asphalt concrete (DPAC) with aggregate size $2/6$. Switching to DPAC 2/6 for highways would result in energy savings of 2–2.5%. These calculations are based on estimations and results with high uncertainty and should therefore be taken as a rough estimate of the potential energy savings. Further research is recommended to further refine and validate the results of this study.

This paper presents an investigation of the time development of dynamic and static elastic moduli of eight mortars made using CEM I cements with contrasting properties. Mixing and the preparation of dynamic testing prism specimens conformed to European standards. A nonstandard specimen and bending test setup was devised for measuring the development of a static Young’s modulus. It was determined that dynamic Young’s moduli determined using an ultrasonic pulse velocity test are often, but not always, greater than those determined using a resonant frequency test. The ratio of a static Young’s modulus to a dynamic Young’s modulus for a particular cement mortar increased nearly linearly with increasing static modulus after 3 days, and this increase can be predicted using the measured 3-day static modulus. In addition, methods for predicting the increase in the static and dynamic modulus and decrease in Poisson’s ratio of mortars, from age 3 to 56 days, using measured 3-day elastic moduli, are presented. Predicted 56-day values of static Young’s modulus, dynamic modulus, the ratio of these, and Poisson’s ratio for the eight different mortars were within 5% of the measured values. The observed relations among different elastic properties may be useful for verification of prediction models.

Accurate deterioration models play a critical role in designing and managing transportation infrastructure. Regular models simply consider loading factor and its relative uncertainties. However, climate and environment impacts are not considered, or are just used as certain variables. Thermal cracks and moisture distresses are principal distress forms in cold regions. In this study, a freeze-thaw (F-T) cycle test was used to simulate the influence of adverse weather conditions in cold regions, like moisture and temperature impact. Then method of moments was applied to analyze the pavement reliability functions with various uncertainties. The analytical results showed that the resilient modulus of asphalt concrete mixture declined under F-T cycles. Consequently, pavement structure capacity was reduced. The results also illustrated that the reliability method was capable of accommodating uncertainties in pavement parameters. The sensitivity analysis indicated that F-T cycles had a significant impact on estimating reliability, especially with a large coefficient of variance. The larger the coefficient of variance, the faster the decline in reliability. Reliability analysis results indicate that a decrease in the variability of F-T cycles can significantly increase the estimated reliability. As a result, F-T cycles with uncertainty harm the pavement loading capacity, which should not be neglected in actual engineering. This paper also proposes some instructions for simulating pavement performance models.

An innovative uniaxial compression test, capable of simulating the confinement and temperature condition in actual pavement, was developed in this study to evaluate the deformation of asphalt mixtures. Small-diameter loading head was utilized to create a confinement inside the specimen, which is similar to that in the field. Optimized loading head size was determined to provide the best confining effect. To reproduce the actual pavement temperature distribution in the tested specimen, a finite-element method (FEM) model was first developed to predict temperature at different depths of a pavement. Then, the laboratory temperature control system was calibrated by monitoring the temperature inside a dummy specimen to ensure the temperatures at different depths of the specimen are the same as in the pavement. Cylindrical specimens with different composition of mixtures were prepared for the uniaxial test to evaluate the deformation of the typical pavement structure at various temperatures, vehicle speeds, and load levels. The developed test method clearly differentiated different materials and reflected the influence of temperature, load time, and level. Test results showed high temperature increased the permanent stain. When the highest ambient temperature level was higher than 28°C, the test effectively differentiated different types of materials. In addition, low vehicle speed and overload significantly increased rutting potential of pavement.

Portland cement is a common sealing material used in wellbores for geological carbon sequestration. Two types of portland cement were reacted with carbon dioxide (${\mathrm{CO}}_2$) in supercritical, gaseous, and aqueous phases, under various pressure and temperature conditions, to simulate a cement-${\mathrm{CO}}_2$ reaction along the wellbore from the carbon injection depth to the near surface. In this study, two types of cement were used: Korean Standard (KS) portland cement (Type I) and American Petroleum Institute (API) class G portland cement. The top halves of hydrated portland cement sample columns ($14\text{-}\mathrm{mm}\mathrm{diameter}\times 90\text{-}\mathrm{mm}\mathrm{long};\mathrm{water}\text{-}\mathrm{to}\text{-}\mathrm{cement}\mathrm{ratio}=0.5$), including additives such as fly ash, were reacted with ${\mathrm{CO}}_2$ in an unsaturated (dry, no contact with water) condition. The bottom halves of the columns were reacted with ${\mathrm{CO}}_2$ in a saturated (wet, in contact with water) condition. These conditions were maintained under high pressure (8 MPa) and temperature (40°C) for 10 and 100 days to determine the potential of this process for carbon sequestration. To perform a relative quantitative analysis (RQA) of cement carbonation, an aragonite-calcite equation was proposed. The degree of carbonation was determined according to the type of cement, the reaction period, and the amount of fly ash. The characterization of the cement was performed using X-ray diffraction spectroscopy (XRD), field emission scanning electron microscopy (FE-SEM) with an energy dispersive spectrometer (EDS), and thermogravimetry-differential thermal analysis (TG-DTA). The relative quantitative analysis of cement carbonation proposed in this study has the advantages of being easier and faster to perform than the general quantitative method.

In the production of conventional paving blocks, it is usual to use a minimum of $210\mathrm{kg}/{\mathrm{m}}^3$ of cement. However, when portland cement is produced, it impacts negatively on the environment due to carbon dioxide emissions. Therefore, this paper investigates the use of waste and by-product materials, such as run-of-station ash (ROSA), basic oxygen slag (BOS), ground granulated blast-furnace slag (GGBS), plasterboard gypsum (PG), and cement bypass dust (BPD) to reduce the amount of cement in paving blocks. The combinations of binary and ternary blends in different mixes are considered. Tensile strength, skid/slip and freeze/thaw resistance of paving blocks, verified that a cementitious mix containing ROSA up to 60%, GGBS up to 55%, BPD up to 25%, and plasterboard gypsum PG up to 5% by weight can replace portland cement without having any substantial impact on the strength or durability of the blocks. XRD and XRF tests of selected mixes have been presented and discussed. Concrete blocks prepared with OPC/GGBS/BPD can reduce cement content by up to 30% in comparison to the percent of cement used in factories.

This paper concentrates on the changes on the corrosion rate of the steel bars of RC columns due to their wrapping with glass fiber–reinforced polymers (GFRPs). RC cylindrical laboratorial specimens, both unwrapped and wrapped with GFRP, were immersed in a sodium chloride solution for 20 months. The changes on concrete resistivity and the corrosion process were followed by open potential measurements and electrochemical impedance. It was possible to quantify the influence of the GFRP jackets in the solution uptake and on the corrosion of the steel reinforcement. The results showed a delay on the diffusion of the solution into concrete due to the presence of the GFRP, which allowed that the bars remained in a passive state for longer immersion periods. The GFRP barrier lowered the rate of uptake of the solution and the chloride ion penetration. However, the GFRP jacket may have the properties as a physical barrier reduced due to imperfect application. The incomplete concrete saturation makes oxygen available, thus promoting an intense corrosion activity at the rebars.

For the purpose of understanding the mechanism that results from treating expansive soil with lime, a series of tests were conducted on selected Nanyang expansive clay. X-ray diffraction tests indicated that the major clay minerals of Nanyang expansive clay are a mixture of illite and smectite with some kaolinite and chlorite. The scanning electron microscope images obtained at different curing times were used to interpret the change in the microstructure and the formation of new products from the lime treated samples. The atomic absorption method was adopted to test the concentration of ${\mathrm{Ca}}^{2+}$ and ${\mathrm{K}}^{+}$ in the pore water and exchange complex of lime treated Nanyang expansive clay. The results indicate that (1) cation exchange, ions crowding, formation of $\mathrm{Ca}{(\mathrm{OH})}_2·{\mathrm{nH}}_2\mathrm{O}$, agglomeration, and breaking of clay particles in a high pH environment are the dominant reactions in the early stage of treating expansive clay with lime; and (2) the pozzolanic reaction and carbonation occurred at a late stage after lime treatment (90 days in this study).

This study presents the electrical resistivity responses of saturated cement pastes undergoing cyclic freeze-thaw (F-T) action. An ordinary cement paste (OPC) and a blended paste (CS) containing ground granulated blast-furnace slag were used for the tests, and both pastes had water to binder ratios of 0.5. As the temperature decreases, the electrical resistivity increases. With increasing number of F-T cycles, the maximum electrical resistivity ${\rho }_{\max }$ increases, revealing progressive frost damage. The pronounced frost damage has also been evidenced by the loss of compressive strength and the appearance of visible cracks for both OPC and CS samples. During freezing, discontinuities arise in the electrical resistivity versus temperature curves for both OPC and CS samples, implying the occurrence of ice nucleation. Moreover, the ice nucleation temperature ${\theta }_{\mathrm{INT}}$ increases with F-T cycle number for all samples. The logarithm of electrical resistivity is a linear function of temperature after ice nucleation: $\log (\rho )=P\theta +A$. Both $P$ and $A$ increase linearly with F-T cycle number. The strong correlations between ${\rho }_{\max }$ and ${\theta }_{\mathrm{INT}}$, $P$ and $A$ provide evidence that these parameters could be capable to assess F-T damage of cement pastes.

This paper presents a large-scale direct shear testing of tire-derived aggregate (TDA) of large sizes (25–75 mm). The objective of this research is to obtain and compare the shear resistances of large-sized TDA and TDA in contact with sand, concrete, and geosynthetics. TDAs are pieces of processed and shredded waste tires that can be used as lightweight and quick fills for embankments, subgrades, and retaining walls. A large-scale direct shear apparatus was designed and constructed. The shear box dimensions were 79 cm wide, 80 cm long, and 122 cm tall. The lower shear box was driven by a hydraulic piston, while the upper shear box remained stationary. The horizontal shear forces, shear displacements, and vertical forces were recorded by an automatic data acquisition system. Three normal loads were applied on the TDA to simulate overburden pressures of 24, 48, and 96 kPa (or 500, 1,000, and $\mathrm{2,000}\mathrm{lb}/{\mathrm{ft}}^2$). Duplicate tests were performed to verify the repeatability. The control tests using sand proved that the equipment could obtain comparable and slightly conservative shear strength. The Mohr-Coulomb failure criterion was used to obtain the cohesion (or adhesion) and friction angles of the TDA. The shear testing revealed the difference of failure mechanisms of TDA and sand. For TDA, no peak shear resistance was observed during the entire shearing, and shear resistance continued to increase until the test was terminated at sufficient shear displacement. Further analysis revealed that the shear strength parameters of TDA increase with shear deformation; this represents a challenge in selecting the design parameters of TDAs. The shear strengths of TDA and TDA in contact with other materials are dictated primarily by friction. The friction angles of TDA, TDA on sand, and TDA on concrete are very similar (in a range of 35–39°).

Polyvinyl alcohol (PVA) fiber reinforced engineered cementitious composite (ECC) is a class of high performance cementitious composites with pseudo strain-hardening behavior and excellent crack control when subjected to uniaxial tension. However, the compressive behavior of ECC has not been well characterized in the literature. In this paper, uniaxial compression tests were carried out on ECC with five different mix proportions and compressive strength ranging from 35 to 60 MPa. Complete stress-strain curves were obtained. Based on the test results, the compressive parameters, such as the elastic modulus, engineering strain at the peak stress, the Poisson’s ratio and the toughness index, were studied. A new constitutive model was proposed to express the pre- and postpeak mechanical behavior of ECC under uniaxial compression. The proposed model showed a good agreement with the experimental curves. The model proposed should be a valuable reference for the nonlinear analysis of ECC material in the part of structures under uniaxial compression.

Most previous investigations on foam concrete have been confined to portland cement and the density range of $400–\mathrm{1,600}\mathrm{kg}/{\mathrm{m}}^3$. The present study aims to develop a new foam concrete with a density ranging from 250 to $400\mathrm{kg}/{\mathrm{m}}^3$ by replacing portland cement with magnesia phosphate cement (MPC). Extensive laboratory tests were performed to characterize the fresh properties, strength, water resistance, and thermal conductivity of the MPC foam concrete. In the experimental studies, mixtures were prepared by replacing fine sand with various contents of fly ash. The results show that an appropriate workability value is achieved at a water-solid ratio of 0.30, at which a foam concrete mixture with a good stability and consistency can be produced. Using fly ash to replace fine sand can improve the properties of MPC foam concrete, includings its compressive strength, water resistance, and thermal conductivity. Novel super-lightweight foam concretes with dry densities ranging from 210 to $380\mathrm{kg}/{\mathrm{m}}^3$ were produced, with strengths ranging from 1.0 to 2.8 MPa and thermal conductivities ranging from 0.049 to $0.070\mathrm{W}/\mathrm{m}·\mathrm{K}$.

The stiffness characteristics of four types of asphalt emulsion cold recycled mixtures (AECRMs) were evaluated using the simple performance test (SPT). Factors influencing the dynamic modulus and the applicability of the Witczak model were investigated. Based on the time-temperature superposition principle, the dynamic modulus $|E^{*}|$ master curves of recycled mixtures were constructed using nonlinear-least squares regression techniques. Statistical significance on the basis of one-way analysis of variance was evaluated as a function of cement, aggregate gradation, frequency, temperature, and confining pressure. The Witczak model is suitable for AECRMs and cement-treated AECRMs, and its prediction accuracy was improved by modifying the original Witczak model. The accuracy of the predicted models was evaluated on the basis of the statistical analysis. The one-way analysis of variance results indicated that the constructed master curves were consistent with the experimental test data. Frequency and temperature significantly affected the dynamic modulus, while confining pressure was not significant. Cement and aggregate gradation had a significant effect on the dynamic modulus at high temperatures or at low frequencies, while the effect was not significant at low temperatures or at high frequencies. Furthermore, the results of the statistical analysis showed that the modified and the original Witczak models resulted in a satisfactory fit between the predicted $|E^{*}|$ results and the laboratory measured $|E^{*}|$ data. The modified Witczak model was more accurate than the original model for AECRM.

In this paper, correlations among the compressive, flexural, and splitting tensile strengths of high-performance steel fiber-reinforced concrete (HPSFRC) were analyzed. For the investigation, a large amount of data was collected from the published papers with water/binder ratio in the range of 0.25–0.48, steel fiber volume fraction of 0.5–2.0% with aspect ratio of 40–80, and specimens of 150 mm Ø cylinders and $100\times 100\times 500\mathrm{mm}$ size prisms. Results on the evaluation of the published empirical relations using the collected data indicate a large variation and inapplicability to steel fiber reinforced concrete, which necessitates the determination of empirical relations between the mechanical properties of SFRC. Through a statistical analysis on the data collected, power relations for flexural and splitting tensile strengths as a function of compressive strength, and the relation between flexural and splitting tensile strengths of HPSFRC with $r=0.94$, were obtained. The validity of the proposed models was examined with the experimental data of the present study and earlier researcher, and the integral absolute error obtained is 5.1.

In the present paper, the properties of carbonated steel slag-slaked lime (SS-SL) mixture, such as strength, drying shrinkage, water absorption, soundness, and durability were mainly investigated. Results indicate that after carbonation the strength of the SS-SL mixture increases by $3\sim 4\mathrm{times}$, its drying shrinkage is significantly reduced, and its soundness and durability are greatly improved. Through X-ray diffraction (XRD), mercury-intrusion porosimetry (MIP), environmental scanning electron microscopy (ESEM), and differential thermal and thermogravimetric analysis (DTA/TG), the mechanism of the carbonated SS-SL mixture and its environmental effects were analyzed and discussed.

The use of geopolymer concrete reinforced with fiber-reinforced polymer (FRP) bars is anticipated to address the concerns on the usage of traditional reinforced concrete structures, such as the corrosion of internal steel reinforcement, costly repair and rehabilitation, and development of sustainable infrastructures. To gain wide acceptance in the construction market, the bond between geopolymer concrete and the FRP bar should be investigated first because it is a critical factor that influences the behavior of structures, specifically its strength and long-term durability. In this study, the bond performance of sand-coated glass fiber-reinforced polymer (GFRP) bars into geopolymer concrete with a compressive strength of 33 MPa was investigated under a direct pullout test. The effects of parameters such as bar diameter (12.7, 15.9, and 19.0 mm) and embedment length (5, 10, and 15 $d_b$, where $d_b$ is the bar diameter) were evaluated. The results showed that the maximum average bond stress obtained is around 23 MPa. As GFRP bar diameter increases, the average bond stress decreases. Similarly, the average bond stress decreases as the bond length becomes longer. The specimens with shorter embedment length failed because of pullout of the bars, whereas those with longer embedment lengths failed because the concrete split. The results further revealed that the geopolymer concrete reinforced with GFRP bars have a bond strength similar to that of steel-reinforced geopolymer concrete. Finally, bond-slip models for the ascending branch up to maximum bond stress of the bond-slip curves for GFRP bars and geopolymer concrete were proposed.

The ultrasonic shear-wave reflection coefficient at the interface between a hydrating material and a buffer material was monitored immediately after mixing as a function of time to study setting behavior of self-compacting pastes and concretes. High-impact polystyrene was used as the buffer material because it is very sensitive to early changes. Self-compacting pastes were produced using fly ash and superplasticizer. Initial and final set times were measured and compared with those obtained from the standard penetration resistance test. Both methods showed reproducible results with self-compacting pastes and were able to distinguish fairly small changes in composition. A good correlation was found between set times obtained from the two methods. The self-compacting pastes were seen to have a substantially delayed set as compared with plain pastes. In addition, self-compacting concretes were made and their set times were measured using ultrasonic wave reflection. The method was seen to be quite reproducible for concrete, and concrete set times matched those of the corresponding pastes reasonably well.

This paper presents a laboratory study of the ability of two bacteria to improve the geomechanical properties of a sandy soil by calcium carbonate precipitation. The performance of two bacteria (Sporosarcina pasteurii and Idiomarina insulisalsae) is compared, based on unconfined compressive strength and splitting tensile strength tests. The effects of curing time and the concentration of I. insulisalsae on the strengthening process are also analyzed. Although the optimum environmental conditions for the bacterial growth were not adopted, the potential to improve the geomechanical properties of natural sandy soils is shown by the results. The bacteria I. insuliasalsae is shown to be more efficient than S. pasteurii in strengthening the soil, and increases in the concentration of I. isuliasalsae induce an increase in the geomechanical properties. However, this effect is not proportional to the amount of bacteria, probably due to a lack of nutrient.

In pipeline construction projects when high-plasticity clayey soils are encountered in the excavated trench material, they are typically landfilled and better quality materials are imported from outside quarry sources for use as bedding and haunch-zone materials. This practice has detrimental environmental and cost impacts; therefore, an efficient reutilization of this high-plasticity excavated material to produce controlled low-strength materials (CLSMs) to use as bedding and haunch-zone materials will have major sustainability benefits. As part of an ongoing research study, novel CLSM mix designs were developed by utilizing native high-plasticity clayey soils from the excavated trench material. Due to the high-plasticity nature of the soils, it is essential to address both flowability and density property requirements prior to validating them against other engineering properties. Hence, several CLSM mixtures with the native clayey soils as ingredients were initially designed as per a flowability criterion to establish the optimum quantities of chemical binders and water quantities. Later, these mixes were verified for satisfying a density property criterion. This technical note presents the step-by-step procedure followed in preparing these mixes along with test results obtained from various mixes designed as part of the testing program. Based on these results, it was evident that CLSM mixes with high-plasticity clays can be developed that meet both flowability and density criteria. The success of this research enhances sustainability efforts in pipeline construction projects because this study showed that excavated clayey soils can be successfully reused in CLSM applications rather than landfilling them.