Grouting Repair Research Articles

Study on the Properties of a Novel Geopolymer Grouting Repair Material for the Road Hollowing Diseases

Study on the Properties of a Novel Geopolymer Grouting Repair Material for the Road Hollowing Diseases

New geopolymer preparation methods and its application by recycle of double-waste: ground granulated blast furnace slag and fly ash

ABSTRACT This article mainly studies new geopolymer preparation methods by recycle of double waste:ground granulated blast furnace slag (GGBFS) and fly ash as geopolymer precursor, through different mass ratio of GGBFS and fly ash, to prepare geopolymers by alkali activation, the samples is cured at ambient temperature and the mechanical test is carried out together with the analysis of XRD, SEM and EDS to research the mechanism of strengthening and geopolymerisation. After analysis we find that the sample prepared by 30% mass ratio of GGBFS have good initial strength and short setting time, as well as best mechanical performance, which is attributed to moderate Ca2+ introduction accelerates the speed of geopolymerisation and the reactants of N-A-S-H gel, C-A-S-H gel and hydrated C-S-H help to bridge the gaps between the different hydrated phases, unreacted particles and matrix, result in a homogeneous and compacted geopolymeric sample. When GGBFS mass ratio above 50%, the mechanical of samples is deteriorated due to too much hydrated calcium containing compounds are formed and covered on the unreacted GGBFS particles surface to block further geopolymerisation. The acid attack test and water resistance test are carried out to analysis the durability between 30% GGBFS introduced geopolymer and ordinary Portland cement (OPC). In additional, a field application in case of 30% GGBFS introduced geopolymer grouting repair material indicated desirable construction based on visual observation and ground-penetration radar scanning.

Repair of Underwater Concrete Cracks on Dam Surface: Optimization Analysis of the Grouting Process with Surface Sealing.

The grouting repair process of the sealing baffle on the surface of dam cracks can improve the repair slurry diffusion distance in the cracks; however, the process must be optimized. To address the problem of crack repair technology of underwater dam concrete with one section open and the other closed, a grouting analysis model was established. By adjusting various parameters in the grouting process, the influences of the grouting pressure, position of the grouting hole, diameter of the grouting hole, and water pressure on the diffusion of the Bingham fluid repair slurry in these cracks were studied. The results show that the grouting pressure and diameter of the grouting hole significantly influence the limited diffusion distance of Bingham fluid cement slurry in cracks. With an increase in grouting pressure and grouting hole diameter, the limiting distance of the front surface increases. The influences of the water pressure and position of the grouting hole are small. In addition, through correlation analysis, the degrees of influence of different factors can be sorted, providing the priority factors for actual operation construction.

Effectiveness of Grouting and GFRP Reinforcement for Repairing Spalled Reinforced Concrete Beams

Corrosion of steel reinforcement from chloride exposure can compromise the strength of reinforced concrete structures. Rust formation expands, applying pressure on concrete, resulting in cracks and spalling. Prompt repair is crucial for severe cases of spalling. This research assessed the efficacy of repair strategies for reinforced concrete beams post-spalling, including grouting and different techniques involving Glass Fiber Reinforced Polymer (GFRP) reinforcement. The research examined four variations of reinforced concrete beams, each sized at 150 mm × 200 mm × 3300 mm. Results showed that the standard beam (BK) had an average maximum load capacity of 29.74 kN. In contrast, the grouted beam (BGR) demonstrated a reduced maximum load of 14.39 kN, along with decreased steel and concrete strain compared to BK. This suggests that the grouting repair did not fully restore the beam's flexural capacity after spalling. Incorporating GFRP strips (BGRS) led to a marginal increase in the beam's maximum load, albeit remaining below BK, with lower steel and concrete strain than BK. However, the steel and concrete approached their yield points, indicating enhanced flexural performance. The full-wrap GFRP beam (BGRSF) experienced an 8.08% increase in maximum load compared to BK, with concrete strain surpassing BK, suggesting an enhancement in flexural stiffness. Doi: 10.28991/CEJ-2024-010-07-05 Full Text: PDF

Study on Grouting Repair and Reinforcement Technology of soft Foundation of large diameter Highway Tunnel

Taking the uneven settlement of the foundation of a two-way eight-lane large diameter highway tunnel as the engineering background, the joint grouting reinforcement technology of miniature steel pipe pile and steel sleeve valve pipe is put forward. based on the field measured settlement data and foundation core samples, the effectiveness of repair and reinforcement is analyzed. The research results show that the combined grouting of miniature steel pipe pile and steel sleeve valve pipe can effectively control the settlement of tunnel foundation, and significantly improve the RQD (Rock Quality Designation) value of tunnel foundation, which provides technical reference and basis for the construction of similar projects.

The Performance Analysis of Grouting Repair Effect on the Accuracy of Disturbance Stress Test in Damaged Surrounding Rock Mass.

Disturbance stress assessment is crucial for ensuring the safety of deep engineering projects. Currently, the primary technique for continuously monitoring three-dimensional disturbance stress is the stress relief method, but its accuracy can be compromised by rock damage that occurs after excavation. To mitigate this issue, grouting is employed to repair damaged rock masses and enhance their mechanical properties. However, the impact of grouting techniques on improving the accuracy of disturbance stress testing is challenging to evaluate through laboratory and in situ experiments. To address this problem, numerical simulation technology is employed to investigate disturbance stress testing after the repair of damaged surrounding rock through grouting. The simulation results indicate that grouting repair significantly enhances the accuracy of stress testing. As the depth of damaged rock mass repair increases, the error in stress testing decreases. Achieving complete repair of the initial damage zone during grouting is essential to eliminate errors in stress testing. Expanding on the positive effects of grouting repair on stress testing, a segmented testing method for disturbance stress is proposed. The method involves separately testing the initial stress and stress changes, thereby reducing the stress level within the rock, minimizing rock failure, and enhancing the accuracy of disturbance stress testing. This study provides valuable reference methods, and the outcomes of this research will serve as a foundation for enhancing the accuracy of disturbance stress testing in deep hard rock engineering.

Investigations on the seepage characteristics of polymer grouting body for repairing HDPE geomembrane defects based on LF NMR

As high-density polyethylene (HDPE) geomembranes in landfill liner systems increasingly age and damage, seepage incidents frequently occur and severely threaten the surrounding ecological environment and groundwater safety. Targeted injection grouting with polymer materials can rapidly restore the barrier function by repairing defects in damaged geomembranes. To investigate the sealing mechanisms of polymer grouting bodies with various densities, this study used low-field nuclear magnetic resonance (LF NMR) techniques to monitor and visualize the permeation process within the grouting bodies. The results revealed two failure modes of the grouting bodies under water flows: 1) insufficient interfacial shear strength between the low-density polymer and geomembrane, leading to interfacial leakage; 2) gradual buildup of permeation pressure puncturing the foam cells of the polymer matrix and inducing permeation channels. Selecting polymers with suitable expansion ratios to produce appropriate expansive pressures is crucial to enhance interfacial shear strength while avoiding secondary damages to geomembranes. Increasing the density of the polymer grouting body can also enhance the compressive strength of foam cells and interfacial shear resistance. These are crucial for enabling grouting repair of defects in geomembranes and improving their barrier performance.

Preparation of the geopolymer grouting material by coal-based solid wastes for the aquiclude key strata and its application

The application of grouting to repair cracks in the key strata of the aquiclude is an effective measure to safeguard the overlying aquifer during underground coal mining. However, conventional grouting materials are expensive and can induce serious environmental pollution. In this study, a cost-effective geopolymer grouting repair material was prepared by using coal gangue, fly ash, bentonite, and other additives. The response surface methodology was employed to design the compressive strength and seepage strength tests on the cemented body, and the microstructure of the cemented body was also explored. The results show that when the ratio of coal gangue to fly ash to bentonite is 23:22:5 and the NaOH content is 4 %, the optimal performance of the grouting material is achieved, with a compressive strength of 10.11 MPa and a seepage strength of 2.38 MPa at the curing age of 28 d. The compressive strength and seepage strength of the grouting material are significantly improved by the network structure formed by the cross-linking of ettringite generated from the hydration of the material and the gel of sodium silicate hydrate.

A study on carbon dioxide emissions of high-polymer road maintenance technology based on life cycle assessment evaluation

Road repair and maintenance is the foundation for maintaining the health of roads. High-polymer grouting technology is an advanced non-excavation road repair and reinforcement technique. However, there is limited existing research focusing on this material and technique's carbon dioxide emissions and influencing factors. This study aims to elucidate the carbon dioxide emissions in the life cycle assessment of high-polymer grouting repair technology, using the example of maintenance work on semi-rigid asphalt pavement. The solidification reaction of each kilogram of high-polymer grouting material will release approximately 11.82 g of carbon dioxide. Comparative analysis was conducted by juxtaposing the carbon dioxide emissions at various stages of high-polymer grouting technology with those of cement grouting techniques and traditional excavation-based repair methods, encompassing conventional assessment (CA) on fuel combustion of engineering equipment and comprehensive life cycle assessment (LCA) on the materials production, fuel production, traffic delay, and engineering equipment. The results indicate a substantial reduction in carbon dioxide emissions for highway maintenance projects employing high-polymer grouting repair technology. The carbon dioxide emissions were reduced by 76.1% and 87.3% respectively per kilometer. The primary contribution to carbon dioxide reduction is observed during the construction phase and in terms of alleviating traffic delays. An indirect relationship is established between the carbon dioxide emissions of high high-polymer grouting materials and their strength, providing a reference for dynamically selecting material density in maintenance projects. The analysis of potential strategies to reduce CO2 emission in the transport sector and other industrial sectors suggests that the LCA model has the capability to accurately pinpoint the main contributing factors and CO2 emission levels stemming from specific maintenance processes within the intricate transportation system. The emphasis on enhancing the production technology of high-polymer materials is pivotal for further reducing carbon dioxide emissions in the context of high-polymer grouting repair technology.

Water Consolidation Performance of Acrylic-Polymer-Modified Materials and Their Concrete Impermeability Repair Characteristics.

Acrylic materials exhibit favorable grouting repair performance. However, their curing products are easily inclined to drying shrinkage, and their concrete impermeability repair characteristics have seldom been investigated. To improve material properties, reveal the impermeability repair mechanism, and address drying shrinkage, this study proposed the addition of styrene-acrylate copolymer emulsion (styrene-acrylic emulsion) to the grouting material to prepare two-component acrylate grouting materials. Using orthogonal and single-factor tests combined with physical and mechanical properties, the mechanical properties and impermeability repair performance (physical and mechanical properties combined) of grouting materials were analyzed and studied, and the optimal ratio of each component of acrylate grouting materials was determined. Results show that (1) the hydrogel produced by the reaction of sodium methacrylate with hydroxyethyl acrylate has good physical and mechanical properties. (2) With the increase in the accelerator dosage, the setting time of slurry initially decreases and then increases; as the initiator dosage increases, the setting time of slurry decreases, which is negatively correlated with the initiator dosage. (3) Talcum powder can improve the physical and chemical properties of gel and enhance the reliability and durability of acrylate grouting materials, and the comprehensive performance is the best at a dosage of 3%. (4) Styrene-acrylic emulsion can increase the solid content and reduce the volume drying shrinkage when added to grouting materials. The fractured impermeable specimens were repaired by grouting with prepared acrylate grouting materials and cured for 24 h for the impermeability test, and the water pressure for the 24 h impermeability repair was 1.0 MPa. This study's results provide important reference and basis for revealing the impermeability principle of acrylate grouting materials and evaluating their impermeability.

Experimental Study on Grouting Diffusion Law of the Different Crack Widths in Tunnel Lining

Grouting technology is an important method that has been widely adopted for the crack repair of tunnel lining, but the diffusion law of grouting slurry is still uncertain in tunnel lining cracks. For the sake of exploring the grouting diffusion law of tunnel lining cracks, this paper investigated the grouting diffusion shape and the relation between the diffusion radius and time with different crack widths in tunnel lining which by means of laboratory experiments and statistical analysis. Meanwhile, the diffusion equation of grouting in lining cracks has been established on basis of the grouting diffusion shape and experimental data. Furthermore, it is analyzed the correlation between the experimental values and the calculated values. The results revealed that the diffusion shape can be divided into a circular zone, excessive zone, and elliptical zone in the tunnel lining cracks, and the calculated values of the equation of grouting diffusion are highly correlated with the experimental values. Additionally, it is shown that the diffusion equation can accurately describe the relationship between diffusion radius and time of grouting in tunnel lining cracks. The study results would provide a theoretical basis for the prediction of diffusion radius on grouting repair for tunnel lining cracks.

Numerical and practical investigation of the multiple hole grouting repair law of underground drainage pipeline defects

Numerical and practical investigation of the multiple hole grouting repair law of underground drainage pipeline defects

Mechanical behavior of secondary lining vault void and mold grouting repair considering contact effect

A void in a tunnel’s secondary lining vault endangers traffic safety, as it affects the mechanical properties and the durability of a tunnel’s structure. In this paper, the damage due to a void and the repair effect of mold grouting were studied. In order to consider the contact effect of the waterproof layer, an interface element was used to connect the secondary lining and the primary lining, and the connection stiffness was limited. On this basis, the effect of a void on the mechanical behavior of the secondary lining was studied by numerical simulation. Then, a numerical model of the contact surface between the grouting body and the molded concrete was established and combined with a typical tunnel model. By changing the bonding strength of the contact surface, the relationship between the mechanical behavior of the grouting body and its bonding performance was analyzed, and its influence on the whole lining is discussed. Finally, the effect of mold grouting is discussed on the basis of field tests and the monitoring results. The results showed that the risk of a crack or even failure of the secondary lining increases significantly with the expansion of a void. Considering the contact effect of the waterproof layer, the connection stiffness between the secondary lining and the primary lining was significantly reduced, and the secondary lining showed more obvious independence and integrity. The insufficiency of the bonding strength between the grouting body and the molded concrete led to the loss of shear strength, and the failure would start from the edge of the grouting body and develop toward the middle. In the cases of class III, IV, and V surrounding rock, the recommended shear strength of the contact surface is about 0.65 MPa, 0.85 MPa, and 1.10 MPa, respectively. The construction method of the mold grouting can guarantee the effective bonding between a grouting body and the molded concrete, so as to avoid cracks, block falling, collapse, and other damage.

Preparation and Performance of Water-Active Polyurethane Grouting Material in Engineering: A Review

Polyurethane foam materials have broad application prospects in practical engineering as flame retardants, waterproof coatings, and grout repair materials due to advantages such as light weight, quick forming, and good durability. Due to water's low cost and convenience, water-reactive Polyurethane foam materials are widely used in engineering. The content of the water has a significant effect on the performance of polyurethane foams after molding. Polyurethane foams with anti-seepage and reinforcement effects are used in complex water environments for long durations. This study analyzed the effects of water content on properties and the diffusion mechanism of polyurethane foam materials in water. Additionally, the effect of the water environment on the polyurethane grouting material's properties was summarized. Finally, this study discussed the future research directions of polyurethane foam materials in a water environment.

Study on Propagation Characteristics of Ground Penetrating Radar Wave in Dikes and Dams with Polymer Grouting Repair Using Finite-Difference Time-Domain with Perfectly Matched Layer Boundary Condition

Non-aqueous reactive polymer grouting technology has been widely used in the repair engineering of dikes and dams with shallow diseases. By using the finite difference time-domain method and perfectly matched layer boundary conditions, the calculation model of dikes and dams with shallow diseases such as water-filled cave, air-filled cave and incompact area is established. The propagation process of electromagnetic waves of ground-penetrating radar in dikes and dams with shallow diseases using polymer grouting repair is simulated, and the forward simulation profiles and single-channel waveforms are obtained. The propagation characteristics such as waveform amplitude, waveform shape, transmission time, and reflection time are compared and analyzed. The results show that the forward simulation profiles of dikes and dams with water-filled caves before and after polymer grouting repair present two clusters of hyperbolas, but three clusters of hyperbolas with different amplitudes were observed at 50% repair. The amplitude of the hyperbola and the single-channel reflected waves before repair and 50% repair of the cave and incompact area are greater than those of 100% repair. The propagation characteristics of ground-penetrating radar can effectively explain the degree of polymer grouting repair for dikes and dams with shallow diseases, and provide a theoretical basis for using the ground-penetrating radar to evaluate the effect of polymer grouting technology to repair dikes and dams with shallow diseases.

Research on Mechanical Response of Polymer Grouting Repair for Longitudinal Cracks in Reconstructed and Expanded Expressway Pavement

Polymer grouting materials have been widely used in road repair projects. In order to study the application of polymer grouting materials in repairing the joint cracks and voids of new and old subgrades in the reconstruction and expansion projects of expressways. According to the phenomenon investigation data, ABAQUS finite element software was used to establish a three-dimensional road mechanical response analysis model, and the mechanical response characteristics of the road before and after polymer grouting were systematically analyzed. The research results of the road which was repaired by polymer grouting show that the shear force between the polymer grouting material and the materials on both sides of the old and new subgrades can repair the cracks at the joint and the diseases in the void area of the new subgrade, so as to reduce the displacement and settlement of the road surface. The maximum dynamic stress peak value of the old and new subgrade road surfaces is located at the load action position, and with the increase of the distance from the load action position, the dynamic stress peak value gradually decreases, showing an M-shaped distribution as a whole. The original stress transfer law of the road structure was changed, so that the dynamic stress of the new subgrade is significantly smaller than that of the old subgrade. The critical surface formed between polymer grouting material and subgrade material has a certain shear strength, which reduces the tensile stress and strain between structural layers. It will improve the bearing capacity of the subgrade and at the same time provide a practical reference for the treatment of longitudinal cracks in the reconstruction and expansion of expressway.

Analysis of the Coupling Effect of Thermal and Traffic Loads on Cement Concrete Pavement with Voids Repaired with Polymer Grout

Under the repeated action of traffic and thermal loads, a cement concrete pavement slab may partially lose contact with its base course, and voids may develop underneath the slab. Such distress will greatly impact the pavement performance. To fill the voids and restore the base support to the slab, the technology of polymer grouting has been increasingly adopted in recent years due to its advantages of quick application and high efficiency. There is, however, a lack of research on the mechanistic responses and performance of such a repaired rigid pavement under coupled influences of thermal and traffic loads. Existing literature has mainly focused on normal cement concrete pavement structures (i.e., without polymer grouted voids). This study intends to fill the research gap by investigating the time-domain characteristics of thermal stress response of a cement concrete pavement with underlying voids filled with polymer grout, along with design traffic loads. The finite element method was adopted with a 3-dimensional nonlinear temperature field within the pavement. A program module was developed in the Abaqus FEA software environment for temperature effect analysis. It was found that under the coupling action of thermal and traffic loads, thermal stress had a greater influence on the critical slab stress at the slab corner than those at other slab locations. Through the comparative analysis before and after polymer grouting repair, the critical tensile stress at the slab corner under the vehicle and thermal loads can be effectively reduced. The polymer performance is stable after three years.

Numerical study on the pipe flow characteristics of grouting repairing pastes used in slab track

In this study, the pipe flow characteristics of the grouting repairing pastes (GRPs) used in slab track were investigated based on three-dimensional flowing models taking into account the hydration effects. Firstly, the rheological properties of GRPs at different hydration times were measured and fitted to obtain key rheological parameters of GRPs. Then the flowing models of GRPs in pipes were established based on these rheological parameters and were verified by comparing with theoretical values. Finally, the effects of pressure gradients, pipe diameters and cement hydration on the flow characteristics of GRPs were systematically studied in terms of four indices including plug diameter, plug velocity, average velocity and the velocity ratio. Results show that the increases of pipe diameters and pressure gradients both lead to the growth of flow velocity, causing an inhomogeneity flow of GRPs in pipes. Yield stress of GRPs has the greatest influence on the flow indices. Consistency index contributes more to plug velocity and average velocity while fluid behavior index dominates the velocity ratio. To achieve a homogeneous flow at high flow rate, it is recommended to prepare a grouting repair material with moderate yield stress and low consistency index and fluid behavior index. Moreover, cement hydration causes noticeable decreases of plug velocity and average velocity under the coupling effects of rheological parameters, which may lead to the setting of GRPs near pipe wall and eventually to the occurrence of pipe blockage during transportation. In order to satisfy efficient repairing in short skylight period, it is suggested to adopt a special grouting repair material featured with slow hydration during grouting but rapid hardening after filling in the debonding area.

Dynamic Response Analysis of Buried Drainage Pipes for Polymer Grouting Trenchless Rehabilitation under the Traveling Wave Effect

The polymer grouting nonexcavation repair technology has been widely used in the repair of underground pipeline leaks, but the seismic response to the polymer repair pipeline is currently using a consistent excitation of seismic input without considering the influence of the traveling wave effect. This paper establishes the longitudinal and transverse vibration models of the polymer grout repair pipeline considering the traveling wave effect based on the elastic foundation beam theory. The seismic input uses artificially generated random seismic waves and solves the differential equations for pipeline vibration to carry out seismic response analysis of long‐buried pipelines under three conditions: normal, vacant, and polymer grouting repair. The results show that after considering the traveling wave effect, the reaction of each measuring point on the pipeline has obvious phase characteristics, and the waveform of the distant measuring point has an obvious hysteresis phenomenon; the seismic wave velocity has a great influence on the deformation of the pipeline, and the displacement amplitude of the pipeline increases with the increase of the seismic wave velocity. The peak of pipeline displacement after vacancy will increase by 100%∼300% more than normal, while the difference in pipeline deformation after high polymer grouting is about 25% compared with normal, which means that the bottom vacant will have a great influence on pipeline deformation, and high polymer repair can restore the pipeline mechanical properties to normal levels.

Temperature Field Variation Law of Low Exothermic Polymer Grouting Material in Repairing Void Damage of Frozen Soil Subgrade

In this study, the self‐developed grouting mold was used to study the heat release characteristics of different density polymer grouting material under different temperature conditions. The spatial distribution characteristics of the frozen soil subgrade temperature field under the effect of polymer grouting repair were analyzed. Further, the rules governing the temperature change of a frozen soil subgrade monitoring point under the effect of polymer grouting repair were studied. The heat transfer mechanism of polymer grouting material in frozen soil subgrade was revealed. The results showed that in the void region of the frozen soil subgrade, a discontinuity zone appeared in the temperature field distribution isotherm due to the effect of voids; this zone exhibited a layered radioactive distribution along the two sides of the void area. Furthermore, during the exothermic stage of the curing reaction, the temperature distribution isotherms changed from a layered radioactive distribution to a ring distribution that decreased from the inside to outside. During the natural cooling process, the peripheral temperature of the ring isotherm first decreased and a negative temperature ring‐shaped isotherm gradually formed. Finally, the upper boundary of the influence of the heat energy released by the curing reaction on the frozen soil subgrade temperature field was determined to be 30 cm, and the lower boundary was 20 cm.