Journal of Materials in Civil Engineering

This paper presents the uniaxial compression behavior of steel-polypropylene hybrid fiber–reinforced concrete (HFRC). A total of 30 batches of specimens with different fiber-reinforcement indices in terms of volume fraction and aspect ratio are investigated by the orthogonal experimental method. A variance analysis is conducted to obtain the optimum proportion of hybrid fiber in terms of compressive strength and corresponding peak strain. It is observed from the experimental results that the uniaxial compression behavior of plain concrete can be improved by inclusion of hybrid fibers; it is also noted that the hybrid effect between volume fraction and aspect ratio of steel fiber as well as the volume fraction of polypropylene fiber should be considered as influential factors on uniaxial compressive strength. Furthermore, in comparison to single fiber-reinforced concrete, HFRC exhibits more ductility at postpeak performance. Subsequently, the results are used to develop predictive equations for the strength, deformation, and the complete stress-strain relation of HFRC under uniaxial compression. The developed equations for compressive strength and stress-strain relationship account for the effect of varying fiber volume fractions and aspect ratios; the results obtained by the equations are found in satisfactory agreement with the experimental results. It is believed that the proposed equations can be useful for further analytical investigations and practical engineering simulations.

The purpose of this study was to determine the influence of sawdust addition in soil–cement bricks and evaluate their mechanical properties using ultrasonic techniques and concepts of structural anisotropy. The influence of sawdust inclusion on soil–cement (specimens, bricks, and prisms) was analyzed by measuring tensile strength, compressive strength, modulus of elasticity, and ultrasonic pulses. To determine the relation between mechanical characteristics of soil–cement–sawdust and ultrasonic pulses, the concepts of structural anisotropy and ANOVA were used. Results indicate that the influence of sawdust inclusion on mechanical characteristics of soil–cement depends not only on soil type, but also on the shape and configuration of bricks and prisms. The addition of sawdust to sandy soil increased its compressive strength, elasticity modulus, and ductility. When added to clayey soils, there was a decrease in compressive strength of the soils but an increase in elasticity modulus and ductility. A strong relation between ultrasonic-pulse velocities and soil–cement–sawdust mechanical characteristics was verified.

Concrete block paving is a cost-effective road construction method suitable for medium to low traffic roads. However, this concrete block paving technique is yet to develop as a fully fledged road construction method. Literature review has shown that there are some contradictions among past findings on block shapes and laying patterns. However, field performance has not been evaluated in selecting the most suitable block shape and laying pattern. Therefore, the aim of this research is to evaluate the most effective block shape and laying pattern for roads with medium to low traffic. Under this study, concrete blocks were cast according to the specifications in predetermined shapes, and paving was done with different block shapes and patterns in a road that contains vehicular traffic with a high percentage of heavy trucks and buses. A selected 100 m road length was divided into 10 equal parts, and blocks were paved according to selected patterns and block shapes from a finite-element model (FEM) analysis of a previous study in each different section. Deflection was measured using the Benkelman beam deflectometer, and block displacement was measured using a vernier caliper. The most effective block shape and pattern were selected by comparing deflections and block displacement in each combination of block shape and patterns. The analysis of results shows that the most effective combination of variables for cement concrete block laying are the unistyle block shape, the stretcher and herring block pattern, and the zero or 90° block angle.

This study investigates the effect of Portland cement porous concrete on tire-pavement noise reduction. The acoustical absorption coefficients were measured in the laboratory for porous concrete materials representing combinations of various maximum aggregate sizes, gradation, layer thickness, and composition layers. The laboratory results indicated that porous concrete with a maximum aggregate size of 9.5 mm had the highest acoustical absorption coefficient. They also showed that the peak absorption coefficient depends on the mixture characteristics and the thickness of the specimen. A thickness of 80 mm had optimum absorption. The results from the laboratory study were used to design and build a test road in the field with two test cells. The wet-on-wet construction method was successfully used to build the porous cement friction course over conventional concrete pavement. Tire-pavement noise was measured on the test cells using the close-proximity method under various vehicle speeds and different tire treads. Tire-pavement noise also was measured for other pavement textures to quantify the noise-reduction effect of the porous cement concrete pavement. The field-measured tire-pavement noise clearly showed that the porous cement concrete significantly reduced the tire-pavement generated noise by 4 to 8 dB.

The research objective was the evaluation of surface texture parameters of commonly applied asphalt mixtures without any special requirements regarding noise reduction on one side, and porous asphalt and thin noise-reducing asphalt on the other. The research considered three geometrically and four acoustically relevant surface texture parameters determined by an optical three-dimensional (3D) measuring device based on the strips projection principle. The mean arithmetic height was identified as the most suitable for the geometrical characterization of surface texture and showed the best correlation with the shape factor. The shape factor was recognized as an especially good acoustical properties indicator for the thin noise-reducing asphalt, which was confirmed by the close-proximity (CPX) method measurements, but was unsuitable for the porous asphalt. The considered parameters also have a potential for distinguishing different types of mixtures, providing a basis for their inclusion into the recommended specifications for the thin noise-reducing asphalt, thus contributing to the achievement of the environmentally sustainable transport.

Tensile and shear testing to final fracture of large-diameter, fiber-reinforced polymer (FRP) composite round bars is often challenging because local stress triaxiality near the gripping ends can precipitate premature failure at these locations, instead of in the desired test gauge section. A method using expansive grout materials has been used, though its design is impaired by the lack of understanding of the gripping pressure developed by the confined expansive grout material. In this paper, an analytical solution has been derived to correlate the hoop strain on the outer surface of the confining steel pipe (caused by grout expansion in the steel pipe) to the grout’s elastic modulus and coefficient of linear expansion. By experimentally measuring the exterior surface hoop strains of two different steel pipes, the elastic modulus and coefficient of linear expansion were determined. This solution has been generalized to include the composite bar and predict the gripping pressure at the bar-grout interface for any given pipe and composite bar combination. Based on the analytical results, expressions for key design parameters for improved expansive grout-based gripping systems, including the minimum grip length, optimum dimensions of the confinement pipes, and minimum volume of the grout material, have been provided. Based on the improved design, glass FRP bars of diameters 19.0 to 38.0 mm (0.75 to 1.5 in.) were tested without gripping problems and with failure loads up to 534 kN (126 kip), which significantly exceeds 400 kN (90 kip), the load level identified as a threshold of concern.

There are several approaches for improving adhesion and moisture sensitivity in asphalt mixtures, one of which is to coat the aggregate surface with a suitable agent to change the predominant electrical charges at the surface and reduce the surface energy of the aggregate. In this study, the effects of using Zycosoil as an antistripping additive on moisture susceptibility of asphalt mixtures has been evaluated by determining the mechanism that affects the adhesive bond between the aggregate and asphalt binder using the surface free energy (SFE) method and laboratory dynamic modulus test. The percentage of the aggregate surface exposed to water ($P$ index) has also been calculated by using the measured SFE and dynamic modulus results, and evaluated as an index for the moisture susceptibility of mixtures. The results of the SFE method show that Zycosoil decrease the difference between the free energy of the adhesion of aggregate-asphalt binder in dry and wet conditions, and this difference is equal to the amount of energy released when stripping occurs. Coating of the aggregate surface with Zycosoil decreases this difference, and subsequently causes the mixture to be more resistant to moisture damage.

This paper addresses the use of ground granulated blast furnace slag (GGBS) and reactive magnesia (MgO) blends for soil stabilization, comparing them with GGBS-lime blends and Portland cement (PC) for enhanced technical performance. A range of tests were conducted to investigate the properties of stabilized soils, including unconfined compressive strength (UCS), permeability, and microstructural analyses by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The influence of GGBS:MgO ratio, binder content, soil type, and curing period were addressed. The UCS results revealed that GGBS-MgO was more efficient than GGBS-lime as a binder for soil stabilization, with an optimum MgO content in the range of 5–20% of the blends content, varying with binder content and curing age. The 28-day UCS values of the optimum GGBS-MgO mixes were up to almost four times higher than that of corresponding PC mixes. The microstructural analyses showed the hydrotalcite was produced during the GGBS hydration activated by MgO, although the main hydration products of the GGBS-MgO stabilized soils were similar to those of PC.

The self-healing properties of asphalt materials present a new means to achieve reliable, durable, and sustainable asphalt pavements through maximizing the effect of microdamage recovery. However, healing (healing of fracture damage) normally happens in conjunction with the recovery of viscoelastic deformation, making the analysis of healing complicated. This paper conducts a comprehensive evaluation of the fracture healing properties of asphalt binder under different damage levels while excluding the effect of viscoelastic recovery. It develops a simple healing testing protocol and a data analysis method that can create fracture damage in the material, assess the level of damage before rest periods, monitor the change of material properties during the healing process, and evaluate the effect of fracture healing on material performance. Healing functions are developed to model the healing characteristics of asphalt binder during the rest under different damage levels and temperatures. Based on the testing results for two binders (PG64-28 and PG70-28), it is found that fracture healing dominates the long-term modulus recovery, while the viscoelasticity contributes greatly for early modulus gain right after the load is removed. The fracture healing properties and the recovery of fatigue performance are strongly affected by temperature and the damage level prior to rest.

The effects of Baltic seawater on frost durability of PC concretes using sulfate resistant portland cement and combination of rapid hardening portland cement with silica fume were studied. The freeze-thaw cycles were performed on specimens exposed to the Baltic seawater, 3% sodium chloride solution and deionized water. The freeze-thaw cycles appeared to cause the most extensive internal damage in specimens based on sulfate resistant cement (SR) and exposed to seawater. The most extensive surface scaling was observed in the case of concretes containing silica fume and exposed to deicing salts. Based on the thermo gravimetric and X-ray diffraction analyses it was concluded that extensive internal damage of concrete based on SR was caused by changes of the microstructure due to secondary formation of ettringite, carbonation, and formation of calcite. The results showed also that low ${\mathrm{C}}_3\mathrm{A}$ content of the SR did not fully mitigate formation of secondary ettringite during freeze-thaw cycles. A combination of rapid hardening portland cement and silica fume appeared to form more frost resistant concrete when exposed to seawater.

The design of chemical stabilization of clay soils typically relies on empirical studies that utilize 28-day strength, measured as unconfined compressive strength (UCS) or California Bearing Ratio (CBR), as the design criterion. At present, it is generally not possible to extrapolate the results of individual studies to other soils, mainly because there is no quantitative understanding of the chemical reactions that cause strength increase over time. Accordingly, the objective of this study was to investigate whether quantitative X-ray diffraction (QXRD) can be used to establish a quantitative relationship between the mineralogical (microscopic) and strength (macroscopic) properties of kaolinite clay stabilized lime, portland cement, and Class C fly ash. The UCS was observed to change linearly with dry unit weight and logarithmically with time up to 300 days of curing. The kaolinite content in the stabilized samples also decreased logarithmically with time, accompanied by a concomitant increase in the amorphous content that represents the formation of calcium silicate hydrate (CSH) and calcium aluminate hydrate (CAH). The overall result was that a highly linear relationship was observed between the UCS and the kaolinite/amorphous content as determined by QXRD. This relationship was different for each of the three stabilizers because portland cement and fly ash exhibit additional cementitious reactions in addition to the dissolution of kaolinite to form CSH/CAH. The study indicates that QXRD is a viable method to produce quantitative assessments of soil mineralogy and that it is possible to pursue the development of models that predict strength of chemically stabilized soils as a function of fundamental parameters, including soil mineralogy and dry unit weight.

This research investigation is intended to compare the abrasion resistance of self-consolidating concrete (SCC) with that of vibratory-placed concrete (VPC) and to examine the effects of binder content and water-to-binder ratio ($\mathrm{w}/\mathrm{b}$) on its wear resistance. In comparing SCC with VPC, four mixtures with varying binder contents of 386, 445, 504, and $564\mathrm{kg}/{\mathrm{m}}^3$ (650, 750, 850, and 950 pcy) were prepared at a uniform water-to-binder ratio of 0.35. To investigate the effect of quality ($\mathrm{w}/\mathrm{b}$) and quantity (binder content) of paste on abrasion resistance of SCC, additional SCC mixtures were also prepared with water-to-binder ratios of 0.40 and 0.45. Depth of wear and compressive strength were used to compare experimental results. The results of this investigation revealed better performance of self-consolidating concrete in comparison with vibratory-placed concrete. While compressive strength of SCC mixtures was 15–30% more than the companion VPC mixtures, their final abrasion depths were lower by 50–70%. Similar to conventional concrete, increasing paste quantity and quality of the trial SCC increased abrasion resistance and decreased rate of abrasion.

This study experimentally characterized the mechanical properties of warm-mix asphalt (WMA) prepared with two chemical additives: Evotherm 3G and Rediset LQ-1106, using laboratory-mixed and laboratory-compacted (LMLC) specimens. A conventional stone matrix asphalt (SMA), widely used in expressway overlay projects in the Chicago area, was selected as the control mixture. Two warm SMA mixtures were prepared by adding 0.5% Evotherm 3G and 0.5% Rediset LQ-1106 by weight of binder, respectively. The performances of the control SMA, Evotherm SMA, and Rediset SMA were evaluated and compared through extensive laboratory testing, including complex modulus, loading wheel track, indirect tension, and semi-circular beam at various curing time periods after compaction. This study concluded that both warm SMA mixtures provided slightly lower tensile strengths and complex moduli than the control SMA. However, the rutting and fracture resistance potentials of the two warm SMA mixtures were relatively similar to that of the control SMA. The curing time effect on the performance of the two warm SMA mixtures varied depending on the material property measured as well as the additive type. A strong correlation between strength gaining and curing time for the two warm SMA mixtures could not be concluded.

Studies in recent years have proved that warm-mix asphalt (WMA) additives can effectively improve the rheological properties of crumb-rubber-modified asphalt (CRMA) without significantly affecting its engineering properties. However, limited research has been done to investigate the rheological modification mechanism of WMA additives on CRMA. In this study, CRMA was prepared by mixing PG64-22 asphalt with 18% crumb rubber by weight of asphalt. Evotherm-DAT, a typical WMA additive, was added to CRMA at four percentages: 0, 8, 10, and 12%. Various conventional rheological tests were performed to evaluate the performances of the CRMA with and without Evotherm-DAT additives at different temperatures. In addition, a series of unconventional tests; including environmental scanning electron microscopy (ESEM), chemical composition, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR) spectroscopy; were conducted to investigate the interaction mechanism of Evotherm-DAT and CRMA from the viewpoints of thermal effects, microscopic morphology, chemical composition, and molecular structure. This study concluded that there is no complex chemical reaction between Evotherm-DAT and CRMA. However, Evotherm-DAT affects the state of aggregation of the crumb rubber and the intermolecular forces of CRMA, which in turn changes the rheological properties of CRMA.

This research makes a further contribution to the existing knowledge regarding textile-reinforced concrete (TRC) structural members, and the proposed component combines the advantages of TRC and reinforced concrete (RC). This concrete member was experimentally studied and its analytical formulae were derived. Test results of the flexural experiment study indicated that the beams with the TRC layer had some increases in the first crack load, the yield load, and the ultimate moment capacity, compared with the ordinary RC beams, and furthermore the ultimate moment capacity had significant increases with the increase of the reinforcement ratio of textile. A considerable reduction in the crack width and spacing was also observed for the beam with a TRC layer, and thus the postcracking stiffness of the beam was improved. Furthermore, this concrete member has satisfactory flexural ductility. For a single reinforced concrete beam with a rectangular cross section, two types of limit failure states are presented with respect to different reinforcement ratio of textile, and for each state, the relationship between the reinforcement ratio of textile and the reinforcement ratio of steel bar is derived. The calculation methods for the ultimate moment capacity for three failure modes and the midspan deflection during the entire loading process are also presented. A comparison between the calculated and the experimental results reveals a satisfactory agreement and verifies the feasibility of the formulae.

The use of nanosized titanium dioxide in photocatalytic pavements is a promising approach to combat air pollution. Past research focused on the effects of environmental and operational parameters on photocatalytic efficiency and its performance under laboratory and field conditions. Few studies have attempted to quantify the durability of the technology integrated with in-service photocatalytic pavements. This study developed and tested a new photocatalytic quantification method used to quantify the short-term durability of a ${\mathrm{TiO}}_2$ spray application on two pavement surfaces: concrete and asphalt. This was accomplished through developing a nitrate extraction method that could be used on in-service pavements without requiring core extraction. Results of the proposed method were compared to results obtained from the Japanese Industrial Standards (JIS) method. The experimental program included testing photocatalytic samples in the laboratory for ${\mathrm{NO}}_x$ reduction and nitrate accumulation based on the JIS method. Results were compared to the nitrate measurements using the proposed method, and a correlation factor was developed. The developed method was then used to quantify the durability of a ${\mathrm{TiO}}_2$-treated photocatalytic pavement over a 5-month monitoring period under field conditions. Results suggest that the service life of ${\mathrm{TiO}}_2$ coating in concrete is between 6 and 11 months and between 10 and 16 months in asphalt pavements.

The use of steel to reinforce concrete has been a long tradition, which is made possible by its strength and compatibility with concrete. Steel is also considered an ideal material for carrying out seismic-resistant construction due to its ductility and high-energy-absorption capacity. Raw materials from different sources are used in the manufacturing of steel bars in Pakistan. As a result, chemical composition, crystalline structure, and mechanical properties of these bars can vary from each other. This paper presents the results of chemical and mechanical tests on the cold-twisted ribbed and hot-rolled deformed steel reinforcing bars. Both types of bars are used in the construction industry in Pakistan. Although chemical composition of the bars met the requirements of the respective standards, a significant number of bars were unable to meet the specified strength and elongation requirements. The bar-failure percentage to meet the specified minimum yield strength was as high as 60%. A large variation in the data of rebar strength was noted. Design implications of using these bars were studied and it was found that the failure mode of flexural members may change from ductile to brittle. Therefore, suggestions are made for safe structural design. A reliability analysis is also carried out and modified values of strength-reduction factors in flexure and shear are suggested.

In recent years, efforts have been made to incorporate reclaimed asphalt pavement (RAP) into pavement base or subbase applications by means of cement binder stabilization. This approach, however, may not be an environmentally friendly solution due to the high carbon footprint involved in the production of Portland cement. Recycled concrete aggregate (RCA), on the other hand, has been widely accepted in pavement applications. The sustainable solution of blending RAP with RCA was investigated in this research in an attempt to facilitate the usage of this blend as an alternative pavement subbase material. An extensive suite of geotechnical laboratory tests was undertaken on RAP with contents of 100, 50, 30 and 15% in blends with RCA. Results of the research study indicated that RAP/RCA blends with a low 15% RAP content meet the repeated load triaxial requirements for use in pavement subbase layers. Results of field performance of a pavement subbase constructed with untreated 100% RAP, at a private haul road field-demonstration site, confirmed that it had insufficient strength requirements to meet local road-authority pavement-subbase requirements. RAP and RAP/RCA blends, although found in this study to be not fully compliant with the local road-authorities requirements, could be potentially considered for lower traffic usage, such as haul roads and footpaths.

This paper aims to investigate the viability of using swine waste binder to improve the rheological properties of bituminous asphalt binder. Due to rising bituminous asphalt binder costs, diminishing reserves of crude oil from which asphalt binder is derived, and the gradual paradigm shift toward more environmentally friendly and energy efficient hot-mix asphalt (HMA) mixtures, the asphalt pavement industry is exploring different sustainable alternative binders. Biobinder has the potential to partially or fully replace typical crude-based asphalt. In this paper, biobinder from swine manure is produced by thermochemical liquefaction process at 380°C and 40 MPa (approximately 400 atm) pressure in the absence of oxygen. A Superpave PG 64-22 is then modified with 5% biobinder by total weight of asphalt binder to produce the biobinder. Samples of the base asphalt binder (nonmodified PG 64-22) and samples of asphalt modified with biobinder are characterized by running the Superpave rotational viscosity (RV), dynamic shear rheometer (DSR), and the bending beam rheometer (BBR) tests. Furthermore, Fourier transform infrared (FTIR) spectroscopy investigations were used to validate the chemical bond initiations that caused changes in stiffness and viscosity of the asphalt modified with 5% biobinder from those of base asphalt binder (PG 64-22). The modification resulted in 27% decrease in viscosity of the base binder. The rolling thin film (RTFO)–aged samples of modified binder experienced a 28.9% decrease in average viscosity change when compared with the RTFO-aged samples from the base binder. Additionally, the pressure aging vessel (PAV)–aged samples of modified binder experienced a 62.9% decrease in average viscosity change when compared with the PAV-aged samples of base binder. The rotational viscosity results proved that the addition of biobinder (swine waste asphalt binder) can reduce the viscosity of the asphalt binder. Furthermore, the modified binder had lower complex moduli and phase angles compared with the base binder (based on DSR results). The BBR results indicated that biobinder had the potential to improve the thermal cracking performance of conventional asphalt binders by reducing the creep stiffness and increasing $m$-value. The BBR results proved that the modification of the PG 64-22 induces a one grade jump on the lower temperature side. The functional groups in typical petroleum-based asphalt binders remained unchanged after the addition of the biobinder to the PG 64-22 binder. Additionally, the FTIR spectra showed that addition of biobinder decreased the stiffness of the PG 64-22 binder through the reduction in molecular carbonyl and sulphoxide bond chains at high temperature. This research investigation provides useful rheological and morphological guidance on the use of swine waste binder as an asphalt binder and mixture modifier.

Large quantities of sawdust waste are generated daily by the logging and lumbering industries, and their safe disposal is a major concern worldwide, whereas the properties of some lateritic soils make them undesirable for use in engineering construction. This paper presents the results of a laboratory evaluation of the characteristics of lateritic soil (LS) stabilized with sawdust ash (SDA), subjected to British standard light (BSL) compactive effort to determine their index, compaction, unconfined compressive strength (UCS), and California Bearing Ratio (CBR) results. The results of the laboratory tests show that the properties of LS improved when stabilized with SDA. The particle-size distribution improved from poorly graded, sandy, gravelly material for 100% lateritic soil and silty material for 100% SDA to the gradation with 94.9–99.9% coarse aggregates of sand and gravel, described as gravelly sand and sandy gravel material for SDA-stabilized LS. The CBR results obtained from the study show that, using the Nigerian general specifications, the maximum CBRs of 19.4% (soaked for 24 h) and 24.1% (unsoaked) achieved for the mix proportion (70% LS + 30% SDA), which falls under American highway and transportation industry standards, can be used as subgrade material. This research provides results for the evaluation of SDA-stabilized LS as highway construction material, as it is based on CBR determination, a limited parameter that does not provide information concerning all important solicitations that flexible pavement materials are subjected to, even if still used in developing countries. Further work may be encouraged to assess the resilient modulus of this material under cyclic load as well as the assessment of permanent deformation of SDA-stabilized LS.

This article focuses on the characteristics of rigid plastic foam building insulation (RPFBI), one of several types of insulation available for new and retrofit applications. Most RPFBI currently in service incorporates a low thermal conductivity and low-flammability blowing agent within the cells of the foam matrix to enhance thermal and fire performance. Blowing agents diffuse out of the foam matrix with time, and environmental gases diffuse in, with concomitant changes in performance. To address the thermal performance issue, international standards organizations have developed standards that define thermal performance averaged over a specific time frame or assumed lifetime. These standards have several limitations that may result in inaccurate estimates of long-term performance, as well as confusion among stakeholders. None of the standards address possible changes in fire performance through time. This paper presents a review of the standards and literature regarding thermal and fire performance of RPFBI, and a call for harmonization and consistency across standards addressing thermal performance, fire behavior, durability, and service life.

Laboratory tests were conducted to evaluate the resilient modulus and rate dependencies of unbound reclaimed asphalt pavement (RAP), crushed limestone, and crushed gravel prepared with the same gradation and equivalent compaction work. Resilient modulus, permanent deformation, and strain energy loss were studied through repeated triaxial and creep testing at different temperatures. The results from this study indicated that RAP tended to have higher resilient modulus when tested as unbound aggregates. However, the permanent deformation of RAP tended to be higher than the crushed stones at ambient temperature. Due to viscoelasticity, the strain (load) rate and temperature dependency of unbound RAP base material was significantly higher than those of crushed limestone and gravel. The temperature dependency of unbound RAP base could significantly affect the performance of asphalt pavements.

The objective of this paper is to investigate the relationship between the chemical shrinkage and electrical resistivity of portland cement pastes during the first 3 days. Plain cement pastes with water to cement (W/C) ratios 0.3, 0.4, and 0.5 were used in this paper. Chemical shrinkage was measured by dilatometry according to industry standards for test methods for chemical shrinkage of hydraulic cement paste. Electrical resistivity was measured by a noncontacting electrical resistivity apparatus. The relationship between electrical resistivity and degree of hydration was investigated. The results obtained show that the relationship between chemical shrinkage and electrical resistivity appears to be roughly linear after 12 h. Note that the electrical resistivity after 12 h can be used to determine the chemical shrinkage and degree of hydration.