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To develop high-performance microfine cementitious grout (HPMCG), the matrix [microfine Portland cement clinker (MPCC) + flue gas desulfurizing gypsum (MFGDG) + calcium carbonate (MCC)], mi...

Polyurethane grouting can be used for antiseepage and reinforcement in underground construction. Understanding the diffusion characteristics of polyurethane grout is critical for good grout...

The primary goal of this study is to assess the characteristics of coal ash–based controlled low-strength material (CLSM) mixtures made with a cementless binder for the feasible usage as a ...

Steel-reinforced grout (SRG) materials are thin laminates made of continuous fabrics of high-strength steel cords embedded within a cementitious matrix. This paper investigates the mechanic...

Cement-based grouting materials can be applied to reinforce unsafe rocks of stone carvings that are attached to or carved out of cliffs. However, studies on the evaluation, that is, the pro...

Rocklike specimens with a grout-infilled flaw having different inclination angles were prepared for uniaxial compressive tests to study the effect of types of grouting materials and flaw in...

In this investigation, highly sensing smart cement grouts were developed using 0.8 water-to-cement (w/c) ratio and adding up to 3% sodium silicate. The sensing grout was also used to repair...

Passive (site) stabilization is a novel technique for the mitigation of seismic liquefaction which uses low-pressure injection of colloidal silica in the pores of a granular soil. The appli...

Field-cast cementitious grouts are commonly used for connecting adjacent prefabricated bridge deck elements. These grouts can exhibit high shrinkage levels and are susceptible to premature ...

Polyurethane has been widely used as new chemical grouting material. Expansion characteristics caused by chemical reactions make polymer grout different from other types of grout. To throw ...

(FCT/MCTES) through the scholarship SFRH/BPD/108427/2015. The authors would like to acknowledge the support from the strategic project UID/CTM/50025/2013. This paper puts forward a new hydrophobic silica fume and assesses its contribution to the performance improvement of grouts for stone masonry consolidation. The experiments were conducted using different dosages of hydrophobic silica fume with natural hydraulic lime grouts in the presence of a polycarboxylate-based high-range water reducer. Results revealed that the effects of hydrophobic silica fume on properties of natural hydraulic lime grouts optimize the use of ordinary silica fume. Remarkable rheological performance was obtained in the presence of hydrophobic silica fume: the plastic viscosity and yield stress were reduced compared with the ordinary silica fume. For mechanical strength aspects, it was found that hydrophobic silica fume slightly affected the flexural and compressive strength; however, the values obtained are suitable for the old stone masonry consolidation purposes. It was also observed that water capillarity was substantially reduced as a result of the water-repellent behavior of hardened grouts. This study suggests that the promising effectiveness of this new silica fume for injection grouts opens the way for it to be used in many other applications. authorsversion published

An acrylamide-based chemical grouting system has been developed that allows users to initiate the curing process on demand. After heating a localized area, the curing reaction propagates th...

Polyurethane materials can be used for nondestructive maintenance of infrastructure, such as slab lifting through injection in a road or railway. Understanding the mechanical behavior and m...

This research focused on the strength characteristics of superfine cement-grouted sand with various gradations and relative densities. At first, grout properties of superfine cement suspensions were studied. The sedimentation and the setting time increased but the viscosity decreased as the water-cement (W/C) ratio increased. Additionally, the groutability of superfine cement suspensions with different W/C ratios into various graded sand specimens having different relative densities was tried. The groutability of suspensions especially into the fine sand specimens was successful with certain W/C ratios and increased as the W/C ratio increased but decreased as the relative density increased. Grouted sand samples remained in tanks filled with water at a temperature of 20°C until testing time and subjected to unconfined compressive strength (UCS) tests at different time intervals. The UCS of grouted sand specimens decreased as the W/C ratio increased, but it increased as the relative density increased. The UCS of grouted fine sand was greater than that of medium sand. Furthermore, the UCS of grouted samples increased with time. © 2016 American Society of Civil Engineers.

This paper presents piezoelectric-based passive/active methods to reliably detect and quantify defects in mass concrete or grout structures. A dual-mode sensing methodology that makes use o...

Backfilling and injection of granular materials into mining induced voids, separated beddings, and cracks, as either diluted slurry or concrete paste, is widely used to control coal mine subsidence. As a viable environmental solution, mine waste and rejected materials from underground coal seams are used in both backfilling and injection mine operations. During longwall mining, the grout slurry is pumped into the separated beds of the fractured rock mass through a pipeline connected to a central vertical borehole, which is drilled deep into the interburden rock strata above the coal seam. Either as dilute slurry or thick paste or cake, the fill material normally needs to travel a significant distance in a long pipeline. A blockage can occur in the pipeline when the slurry velocity falls below a certain critical threshold value, indicating a material phase change from cohesive-viscous to cohesive-frictional. In a previous study of radial flow through disks, complete analytical solutions of the required pump pressure versus fluid volume rate were presented for such slurries, categorized as frictional Bingham-Herschel-Bulkley fluids. This paper is an extension to the theory of fluid mechanics to this type of flow in uniform circular pipes. General analytical solutions were developed for complex fluids in velocity and pressure gradients and velocity and pressure as a function of pipe length, from which special and familiar equations for simpler fluids are derivable by mathematical reduction of the general equations. This study differs from the previous research in consideration of the variable shear parameters rather than fixed values, inclusion of total nonlinear behavior, and implementation of a friction function to mimic behavior of the depositing and consolidating stiff slurry, which can cause a significant pressure rise as a result of the increased shear resistance.

In this study, the effects of initial temperature, catalyst content, and activator content on the gelling time and maximum curing temperature of two polymeric grouts were investigated. Because the grouts are used in various environmental conditions, the grouts were investigated at three different initial temperatures (4.4, 15.7, and 26.7°C, or 40, 60, and 80°F). The catalyst and activator contents varied from 0.5% to 3% of the total weight of grout mix. Gelling times for the polymer grouts were measured, and the curing temperatures for the mixtures were monitored during and after the gelling process. The gelling time reduced with increased catalyst and activator contents and increased initial temperature for both the polymer grouts. One grout exhibited shorter gelling time and lower temperature rise during the gelling process than the other grout. Both artificial neural network (ANN) and nonlinear relationship (NLR) models were used to predict the observed grout behaviors. For each grout, a total of 48 te...

There is an increasing need to identify the effect of mix composition on the rheological properties of cementitious grouts using minislump, Marsh cone, cohesion plate, washout test, and cubes to determine the fluidity, the cohesion, and other mechanical properties of grouting applications. Mixture proportioning involves the tailoring of several parameters to achieve adequate fluidity, cohesion, washout resistance and compressive strength. This paper proposes a statistical design approach using a composite fractional factorial design which was carried out to model the influence of key parameters on the performance of cement grouts. The responses relate to performance included minislump, flow time using Marsh cone, cohesion measured by Lombardi plate meter, washout mass loss and compressive strength at 3, 7, and 28 days. The statistical models are valid for mixtures with water-to-binder ratio of 0.37–0.53, 0.4–1.8% addition of high-range water reducer (HRWR) by mass of binder, 4–12% additive of silica fume as replacement of cement by mass, and 0.02–0.8% addition of viscosity modifying admixture (VMA) by mass of binder. The models enable the identification of underlying factors and interactions that influence the modeled responses of cement grout. The comparison between the predicted and measured responses indicated good accuracy of the established models to describe the effect of the independent variables on the fluidity, cohesion, washout resistance and the compressive strength. This paper demonstrates the usefulness of the models to better understand trade-offs between parameters. The multiparametric optimization is used to establish isoresponses for a desirability function for cement grout. An increase of HRWR led to an increase of fluidity and washout, a reduction in plate cohesion value, and a reduction in the Marsh cone time. An increase of VMA demonstrated a reduction of fluidity and the washout mass loss, and an increase of Marsh cone time and plate cohesion. Results indicate that the use of silica fume increased the cohesion plate and Marsh cone, and reduced the minislump. Additionally, the silica fume improved the compressive strength and the washout resistance.

An experimental program was carried out to clarify the effect of chloride-induced corrosion on posttensioned concrete (PC) beams under different grout conditions using the electrically accelerated corrosion testing method. A series of accelerated corrosion tests were performed to evaluate the influence of insufficient grout condition on corrosion of sheath and prestressing tendon. The radial pressure surrounding the sheath during the corrosion process was also investigated. After a period of accelerated corrosion, the mechanical behavior of the deteriorated PC beams was clarified through loading tests. Prestressing tendon corrosion and its correlation with beam load-carrying capacity was also investigated. The results of the experiments demonstrate a significant influence of corrosion of sheath and prestressing tendon on load-carrying capacity of PC beams. The width of the corrosion crack in PC beams increases with grout filling level inside the sheath. The presence of water inside the sheath leads to increased rates of corrosion of the sheath and prestressing tendon, resulting in an earlier deterioration in the load-carrying capacity of PC beams.

An experimental investigation of the behavior of interlocking grouted stabilized sand–fly ash brick masonry under unaxial cyclic compressive loading with different bed joint orientation is presented. Five cases of loading at 0, 22.5, 45, 67.5, and 90° with the bed joints were considered. The brick units and masonry system developed by Professor S. N. Sinha are used in the present investigation. Eighteen specimens 500 mm×100 mm×700 mm and 27 specimens 500 mm×100 mm×500 mm were tested. The envelope stress-strain curve, common point curve, and stability point curve were established for all five cases of loading with respect to the bed joints. A general analytical expression is proposed for these curves which fit reasonably well with the experimental data. It was inferred that the peak stress of the stability point curve may be considered as the maximum permissible stress level and is found in the range of 0.745–0.775 times the masonry strength depending upon the load case. It was also inferred that the permi...

Pipe-in-Pipe (PIP) configurations are considered as a practical solution to deepwater oil production to prevent hydrate formation and paraffin deposition during the transportation of crude oil to production facilities. The optimal design of a PIP configuration requires a balance between the structural performance and the thermal insulation of the grout material used to fill the annular space. In this study, the effect of aggregates (4–19.1 mm) , sand (0.4–5 mm) , and microspheres (

The low-viscosity stabilizer, colloidal silica CS, is extensively used as a grouting material in the construction of grout curtains to prevent fluid movements. It is a low viscosity and nontoxic material, which is suitable for injection to stabilize/solidify fine grained soils. It is also used in the in situ treatment of hazardous waste as a stabilizer/solidifier. Once the CS solution is injected into contaminated soil, it moves through the pores inside the soil matrix and initiates the stabilization/solidification process. The viscosity of the CS mixture increases while it moves until complete solidification occurs. In this paper, the transport of CS during injection was simulated at the microscopic level to understand the stabilization/solidification process. The microscopic behavior/movement of CS stabilizer inside anisotropic granular soil during grouting was simulated by numerically solving the Navier-Stokes equation. The change in gel viscosity with time was used to model the movement of CS during injection. A model parameter vmin, the minimum velocity for CS to become a solid, was introduced. The simulation showed that during the grouting of fine sands, solidification starts at the soil surface and expands to fill the majority of voids within 1.2 h. The simulation of CS grouting of different soil types, soil compaction levels, and soil anisotropies showed the impact of soil parameters such as grain size distribution, void ratio and anisotropy on velocity contours and the final solidification. This microscopic model can be further improved to be used in the design of grout curtains, especially for the determination of the ability to grout soils and the size of stabilizer plume in such stabilization projects.

Passive site stabilization is a new technology proposed for nondisruptive mitigation of liquefaction risk at developed sites susceptible to liquefaction. It is based on the concept of slowly injecting colloidal silica at the edge of a site with subsequent delivery to the target location using natural or augmented groundwater flow. Colloidal silica is an aqueous dispersion of silica nanoparticles that can be made to gel by adjusting the pH or salt concentration of the dispersion. It stabilizes liquefiable soils by cementing individual grains together in addition to reducing the hydraulic conductivity of the formation. Centrifuge modeling was used to investigate the effect of colloidal silica treatment on the liquefaction and deformation resistance of loose, liquefiable sands during centrifuge in-flight shaking. Loose sand was successfully saturated with colloidal silica grout and subsequently subjected to two shaking events to evaluate the response of the treated sand layer. The treated soil did not liquefy during either shaking event. In addition, a box model was used to investigate the ability to uniformly deliver colloidal silica to loose sands using low-head injection wells. Five injection and two extraction wells were used to deliver stabilizer in a fairly uniform pattern to the loose sand formation. The results of the box model testing will be used to design future centrifuge model tests modeling other delivery methods of the grout.

This paper presents a study on the effectiveness of two forms of reinforced grout confining systems for hollow concrete block masonry. The systems considered are: (1) a layer of grout directly confining the unreinforced masonry, and (2) a layer of grout indirectly confining the unreinforced masonry through block shells. The study involves experimental testing and finite-element (FE) modeling of six diagonally loaded masonry panels containing the two confining systems. The failure mode, the ultimate load, and the load-deformation behaviors of the diagonally loaded panels were successfully simulated using the finite-element model. In-plane shear strength and stiffness of the masonry thus determined are used to evaluate some selected models of the confined masonry shear including the strut-and-tie model reported in the literature. The evaluated strut width is compared with the prediction of the FE model and then extended for rational prediction of the strength of confined masonry shear walls.

EN 934-2 “Admixtures for concrete, mortar and grout Concrete admixtures. Definitions, requirements, conformity, marking and labelling” requires that any increase in the air content shall not be more than 2% by volume over that obtained from the reference mix, and most types of superplasticizers (SPs) easily meet this requirement. Some types may even reduce the level of air, and this can result in a less cohesive mix, which may be more prone to bleed and segregation or may leave the mix feeling harsh and difficult to handle. Unfortunately, some types of superplasticizers increase the level of air. Too high a volume of air has been overcome using an antifoaming agent. The influence of new-generation type superplasticizer and antifoaming admixture (AFA) on the air content and workability of high performance self-compacting concrete (HPSCC) is analyzed in this paper. The purpose of this study was to examine the influence of the admixture type on pore size distribution, compressive strength and frost r...

This study investigates the effect of the strand-to-duct area ratio on the shrinkage cracking behavior of posttensioning grout. The free shrinkage behavior of grout was evaluated using various duct diameters. Test results indicated that the expansion and shrinkage strains of grout increased with the duct diameter. The strain of a restrained strand was barely affected by the number of strands but was significantly affected by the strand-to-duct area ratio. The specimen with a strand-to-duct area ratio greater than 0.3 showed shrinkage cracks in fewer than 30 days. Increasing the strand-to-duct area ratio shortened the cracking time. All the test specimens showed bleeding immediately after pumping, along with air void pockets in the grout.

The effect of colloidal nanosilica on the fresh and rheological parameters, plastic shrinkage, heat of hydration, and compressive strength of cement-based grouts is investigated in this paper. The fresh and rheological properties were evaluated by the minislump flow, Marsh cone flow time, Lombardi plate cohesion meter, yield value, and plastic viscosity. The key parameters investigated were the dosages of nanosilica and superplasticizer and temperature of mixing water. Statistical models and isoresponse curves were developed to capture the significant trends. The dosage of nanosilica had a significant effect on the results. The increase in the dosage of nanosilica led to increasing the values of flow time, plate cohesion meter, yield stress, plastic viscosity, heat of hydration at 1 day and 3 days, and compressive strength at 1 day, while reducing the minislump, plastic shrinkage up 24 h, and compressive strength at 3, 7, and 28 days. Conversely, the increase in the dosage of superplasticizer led ...

The paper presents the results of an experimental investigation conducted on clay bricks and different types of restoration products commonly available on the European market, specifically a tixotropic mix for production of mortars and structural plasters, two cement-free binders for dehumidifying mortars, a cement-free grout to be used as filler for voids and cavities in masonry structures, a cement-free dehumidifying mortar for the restoration of damp stone, brick and tuff masonry, and a one-component mortar for plaster repair. Prism-shaped specimens were produced using single materials and coupled materials. They were subjected to static compressive tests for the determination of their mechanical properties and cyclic compressive tests for the analysis of their fatigue behavior; the final aim is to develop an experimental procedure for assessing the effectiveness of strengthening materials. A parameter, α, was defined based on the results of the static compressive tests. It was used for the characterization of the long-term interaction between parent material and restoration mortar. Finally, a simple procedure for selecting an appropriate repair mortar is suggested based on such a parameter.

During the past 20-plus years, designs based on the post-tension segmental concrete box concept have evolved to become prominent in bridge construction. Critical to the safety and longevity of such structures is the integrity of post-tensioning tendons. However, during the past five years, several Florida bridges have suffered tendon deterioration and failure because of strand corrosion at grout voids in which bleed water had accumulated. In some cases, the high-density polyethylene (HDPE) ducts within which the grouted strands reside had cracked. Although none of the tendon failures to date have been related to the HDPE duct cracking, left unaddressed moisture, chlorides, and oxygen will invariably corrode strands in the long-term. In order to assess the cause(s) and mechanism(s) of HDPE duct cracking, fatigue tests were performed upon duct samples retrieved from representative bridges and the results were compared with those from (1) material property determinations of the corresponding ducts, (2) experiments on simulated tendons that were subjected to thermal cycling, and (3) finite element analyses. Based on the outcomes, a mechanism is proposed for the duct cracking and time-to-cracking projections are made for ducts that are still sound.

With little mining information, old abandoned coal workings were grouted beneath a proposed building site. Mine stabilization was found necessary after an investigation of subsidence potential was performed. The investigation indicated that the 67 m deep abandoned mine, although old, still had not collapsed and consequently presented a significant risk of subsidence in the future. Further, based on the history of subsidence over old mines in the area, mine grouting was recommended. To stabilize the mine, about 11,468 m3 of grout were pumped. The grouting was designed to account for the significant amount of rubble which existed in the mine. There were three grout mixes of different flowability characteristics specified. The 1,725 kPa grout was batched at a slump of 10 and 20–22 cm and at a efflux flow rate of 30–40 s. Permeation, squeeze (or intrusion), and compaction grouting was performed per the project specifications. Also, to economize on the amount of grouting necessary, subsidence resistant feature...

This study investigates the roles of contaminant-grout and contaminant-soil interactions on the effectiveness of grouting gasoline-contaminated soil for minimizing contaminant migration by substantially decreasing the permeability of the grouted mass and/or encapsulating contaminant residuals. Experiments were conducted to determine the bleed capacity, unconfined compressive strength, and microstructure of neat microfine grout at three water:cement ratios with up to 20% of gasoline contamination. The gasoline was found to significantly reduce sedimentation, lower the compressive strength, and become encapsulated in the grout matrix. To quantify the effects of various interactions in the contaminant-grout-soil system and the effectiveness of contaminant containment, microfine cement grouts were injected into three gradations of Ottawa sand subjected to six different pregrout scenarios to physically model different degrees of residual saturation. The contaminated sands were determined to have higher permeability and lower strength due to more porous interfacial zones and adsorbed contaminant layers on the sand surfaces. These microstructural features and encapsulated contaminant entities were documented by microscopy. A first approximation of the apparent mass of contaminant residual that may migrate from grouted sand was determined by leaching tests and gas chromatography; results were typically 50% greater in cases where gasoline saturated initially dry sand.

Contaminant migration from polluted sites that are excessively permeable to fluids can be minimized by ground stabilization through grouting with cementitious materials. Analyses of the long term drying process of 2.75 mm diameter samples of cement–bentonite grouted soils from Dover, Del. in an environmental chamber maintained at a temperature of 25°C and relative humidity of 30% indicate that for most samples, the water-filled porosity (0.02–0.033) varied in a quasi-sinusoidal pattern with respect to drying time. Measurements of ultrasonic wave transit time with a James V-Meter correlated in time, with moisture loss determinations by weight loss measurements, show that in the initial 0–65 day drying period, the escape of moisture and consequent increase in air-filled porosity is responsible for the decrease in ultrasonic pulse velocity. Thereafter, increases in pulse velocity values ranging from 50 to 260 m∕s observed for the reaction products at sustained drying at 25°C, provide enough activation energy...

Bentonite slurry without cement is used for seepage barriers such as slurry trenches or grouting, but the sodium-bentonite content in the slurry cannot be increased to more than 100 kg∕ m3 . Slurry with such low bentonite content is not enough to achieve impermeability of the slurry walls or grouting. Using hydrophilic solvents such as ethanol can depress the bentonite swelling, and the liquid limit can be decreased to less than 100%. Therefore ethanol is used for the mixing liquid when preparing the slurry, and the bentonite concentration can be increased to more than 100 kg∕ m3 in the slurry state. Ethanol/bentonite slurry can be grouted to small spaces with sufficient cutoff performance. This paper reports the high potential of ethanol/bentonite slurry for seepage barriers based on the following characteristics: low permeability, smooth groutability, and sealing ability with the substitution of ethanol with water. The high potential of ethanol/bentonite slurry for grouting was confirmed through the fil...

To date, only linear elastic analyses have been used to explain the compression behavior of the concrete masonry prisms. In this study, nonlinear three-dimensional finite element analyses, based on both an elastoplastic approach and an isotropic damage model, have been applied to the compression behavior of hollow block and grouted concrete block prisms. Attention is particularly focused on the derivation of material parameters for concrete, grout, and mortar, and also on the improvement of existing code expressions for prism strength. This paper introduces adequate values for the cohesion and friction angle of the Drucker–Prager yield criterion and material damage parameters for the damage model for the constituent materials. The results of the nonlinear finite element analyses have been observed to be in good agreement with the experimental data in terms of failure mechanisms and ultimate load. Failure modes of grouted prisms are also investigated by evaluating the stress distributions at the outer face...

This paper presents the results of pullout bond tests on fiber-reinforced polymer (FRP) tendons embedded in cement mortar filled steel tubes. The pullout test program involved four types of FRP bars, three types of grouts, and two types of bond lengths. The experimental results have shown that the pullout behavior of grouted FRP tendons are influenced by the material properties and surface conditioning of the tendon. The bond length, surface geometry and manufacturing of the tendon, grout properties, and anchorage radial stiffness have an effect on the bond strength of the tendon to the grout. An analytical model of bond stress–slip relationships for grouted FRP tendons has been proposed, and its effectiveness to represent the entire bond-slip curve has been demonstrated.

The effectiveness of chopped carbon fibers to enhance the thermal conductivity of bentonite-based grout was examined. Fibers of 3 mm and 150 μm in length were added to sodium bentonite and silica sand mixtures at different volumetric concentrations. The thermal conductivity of the resulting composite material was then measured using a non-steady-state needle probe technique. The conductivities of the fibrous materials were compared to bentonite and sand mixtures containing natural flake graphite and milled, compressed exfoliated graphite at corresponding volumetric concentrations. The resulting conductivities for all tested materials increased with the volumetric fraction of additive. However, the 3-mm carbon fibers were more effective as compared to either granular graphite; at a volume fraction of 0.68% the 3-mm fibers were approximately twice as effective as either form of graphite.

This paper describes the results of a six-year laboratory test program to evaluate the performance of chemical-based grouts submerged in a saltwater (brine) environment, simulating a practical appl...