Cement Grout Research Articles

Small scale laboratory monotonic and cyclic pull out testing on grout and resin encapsulated cable bolts

Axial studies on cable bolts can be conducted using various scale testing apparatuses. Large scale testing, while providing a powerful platform for testing, is expensive and time consuming. This study presents details of a small scale pull out testing campaign on cable bolts and investigates the results achieved. Six popular types of cable bolts were studied using an anti rotation apparatus while encapsulated in cementitious grout and resin. The resin samples were tested under both monotonic and cyclic loading patterns. The results showed that grouted bulbed cables require higher displacement to reach their maximum load capacity which is lost at failure, while plain cables tend to hold lower loads for a longer time. Resin samples provided strain softening behaviour with low capacities, particularly in absence of cable indentation or bulbs. Cyclic loading tended to adversely affect the post peak behaviour of the resin samples, especially in the bulbed cables. Failed samples inspected after the testing suggested a non-uniform damage profile along the cable with extensive damage at the exit point transitioning into almost no damage at the entry point.

Research on the Mechanical Properties of Composite Grouting Materials Based on Ordinary Portland–Sulphoaluminate Cement

This study aimed to enhance the mechanical properties of calcium sulfoaluminate cement grouting materials (HCSA) by investigating the effects of ordinary Portland cement (OPC) content, the ratio of quicklime to gypsum, and the dosage of sodium aluminate on the compressive strength of the OPC-CSA composite system. The results indicate that as the OPC content increases, the compressive strength of the blended cement initially increases and then decreases, reaching a maximum at a 60% OPC replacement ratio within the experimental group. The addition of an appropriate amount of OPC to the CSA composite system effectively prevents the regression of compressive strength. With an increase in quicklime content, the compressive strength of the samples at various ages first increases and then decreases, with the optimal ratio of quicklime to gypsum found to be 2:8. Furthermore, sodium aluminate, used as an activator, when increased in dosage, leads to an initial increase followed by a decrease in the compressive strength of OPC-CSA samples, with an optimal incorporation rate of 0.75%, significantly enhancing the strength of the blended cement. In the orthogonal experiments, the dosage of sodium aluminate was identified as the most influential factor affecting the compressive strength of the composite grouting materials.

Experimental research into the injectability of cement grouts in reef limestone

Experimental research into the injectability of cement grouts in reef limestone

Bond behavior between the deformed steel bar and different types of cementitious grout under reversed cyclic loading

To systematically investigate the bond behavior of deformed steel bars in cementitious grout, direct pullout tests were conducted on 15 sets of specimens by considering five types of cementitious matrixes and three different loading schemes. The failure modes, bond stress-slip curves, as well as the bond degradation and cumulative energy dissipation of specimens under reversed cyclic loading, were compared and analyzed. Results indicate that splitting pull-out or pull-out failure modes were observed, and pull-out failure was the most common failure mode of the specimen (accounting for 91 %) due to the installation of stirrups and the sufficiently short anchorage length. Meanwhile, regardless of the loading scheme, the general relationship between the magnitude of maximum bond stress of specimens composed of different cementitious materials was shown as C60＞CGM-270＞CGM-300＞CGM-340＞CGM-380, while there was no consistent pattern in relative slippage. Moreover, the relationship between the degradation of the maximum bond stress and stiffness of each specimen under reversed cyclic loading was shown as CGM-380 >CGM-340 ≈CGM-300 >CGM-270 >C60. The degradation mainly occurs in the first two cycles, and then gradually stabilizes. Furthermore, the cumulative energy dissipation relationship of specimens with different materials was shown as C60 >CGM-270 >CGM-300 >CGM-340 >CGM-380 under the reversed cyclic loading. The above investigations could provide theoretical support for the evaluation of ductility and energy dissipation of concrete members strengthened with cementitious grout under earthquake actions.

Retardation of Chlorine-36 by Cementitious Materials Relevant to the Disposal of Radioactive Wastes

The activation product chlorine-36 (36Cl) is an important radionuclide within the context of the disposal of nuclear wastes, due to its long half-life and environmental mobility. Its behaviour in a range of potential cementitious encapsulants and backfill materials was studied by evaluating its uptake by pure cement hydration phases and hardened cement pastes (HCP). Limited uptake of chloride was observed on calcium silicate hydrates (C-S-H) by electrostatic sorption and by calcium monosulphoferroaluminate hydrate (AFm) phases, due to anion exchange/solid solution formation. Diffusion of 36Cl through cured monolithic HCP samples, representative of cementitious materials considered for use in deep geological repositories across Europe, revealed a markedly diverse migration behaviour. Two of the matrices, a ground granulated blast furnace slag/ordinary Portland cement blend (GGBS–OPC) and an ordinary Portland cement (CEM I) effectively retarded 36Cl migration, retaining the radionuclide in narrow, reactive zones. The migration behaviour of 36Cl within the cementitious matrices is not strictly correlated to the measured sorption distribution ratios (Rd-values), suggesting that physical factors related to the microstructure can also have a distinct effect on diffusion behaviour. The findings have implications when selecting cementitious grouts and/or backfill materials for 36Cl-bearing radioactive wastes.

Mechanical Properties of Iron Tailing Sand Grout Sleeve Joints and Force Analysis.

In this paper, the mechanical properties and internal stress condition of the reinforcing bar sleeve connectors with ferro-tailed mineral sand cementitious grout as filler material were analyzed as research objects. Firstly, an experimental study was carried out on the reinforcing bar sleeve connectors of iron tailing sand grout with a 40% substitution rate of mechanism sand to analyze the mechanical properties of different grout types, age, and reinforcement diameters under unidirectional tensile, high stress, and large deformation of repeated tensile and compressive stresses. Next, five groups of sleeve joints with different anchorage lengths were set up for unidirectional tensile tests. The results show that, with the decrease of the diameter of the reinforcement, the grip force and bond strength of the iron tailing sand grout on the internal reinforcement gradually increase. Under conditions of large deformation and high stress due to repeated tensile loading, the residual deformation and total elongation of iron tailing sand grout sleeve joints are satisfactory. Additionally, the restraining anchorage effect of iron tailing sand grout in the end section is small. The utilization rate and integrity of iron tailing sand grout in the initial anchorage section are better.

Analysis of thixotropy of cement grout based on a virtual bond model

Thixotropy of cementitious materials is a crucial intrinsic property that determines the flowability and workability of cement-based grout. A novel virtual bond model of cement particles is developed in this paper to depict the thixotropy of cement grout. A particulate description of the reversible and erasable interparticle bonds is established based on experimental observations with a focus on the non-contact interactions mainly contributed in practice by calcium silicate hydrates (C–S–H). The structural breakdown of the cement network is realized through bonds breakage under applied motion, and the bonding network recovers with regeneration of interparticle connections that involve reversible hydrate reactions in the mixture. The balance between bond rupture and rebuilding can be tuned by assigning different strength limits for bond breakage. We have implemented this model in the open-source code Yade to carry out 3D discrete element method simulations of a rotational vane system filled with spherical particles, and the results show good agreement with experimental data. The modelling results reveal the transition from a solid-like structure to a fluid-like medium within cement suspensions caused by the evolution of broken interparticle bonds. The results also provide a distinct view of thixotropic variation upon disturbance. This model is extendable to other cohesive materials providing an explicit physical definition of the interparticle interactions. It also provides a theoretical explanation for the empirical estimations of thixotropy common in engineering industries and a potential means of measuring cementitious granular flow that may be useful in future studies.

Study on cementitious grout for scour protection of offshore wind turbine foundations

To study scour-resistant applicability, 6–10% mass ratio of polyurethane (PU) was added to sulphoaluminate cement (SAC) and ordinary Portland cement (OPC) grouts to generate OPCPU and SACPU. Sodium silicate (SS) with slurry volume ratio of 1:1–5:1 was added to SAC and OPC grouts to generate OPCSS and SACSS. The water-cement ratio (w/c) of grout was 0.8–1.5. Fresh-state properties and mechanical properties were investigated. Hydrated minerals and microstructures were analyzed, scouring tests were conducted considering key formulations. The results indicated that SACSS and OPCSS have a shorter setting time and higher strength, which makes them suitable as scour resistance materials. At the w/c of 1.0, OPCSS with a volume ratio of 3:1 and SACPU with 6% PU were selected for scour resistance tests. It showed that maximum scour depths and sediment transports were 7.0–12.2 and 1.1–1.2% as those without reinforcing conditions. The critical shear stress on the seabed under reinforcement is ∼103 times greater than the bed shear stress. This inhibits the occurrence of scouring. The study evaluated the applicability of cementitious reinforcement for scour resistance. This study analyzed material and mechanical properties, hydrated minerals, and microstructures, and conducted scour tests to optimize grouting material ratios for seabed scour protection, providing references for soil reinforcement and grouting protection.

Improvement of Soil Thermal Conductivity with Graphite-Based Conductive Cement Grouts

Improvement of Soil Thermal Conductivity with Graphite-Based Conductive Cement Grouts

Sedimentation-affected engineering performances and microstructures of a hybrid Portland-sulfate aluminate cement grout cast in long tubes

Material sedimentation may have non-negligible impacts on engineering properties of flowable cement grouts, and this issue cannot be addressed by in-lab tests on small size specimens. Herein, sedimentation tests were conducted to a high-strength hybrid Portland-sulfate aluminate cement (P-SAC) grout cast in 6-m-long tubes. Compressive strength and density of the P-SAC specimens at different depths were measured, and microstructures were assessed by X-ray computed tomography (XCT), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Results showed that the hybrid P-SAC grout possessed the superior indices of flowability, expansion and compressive strength. The increasing rates of density and compressive strength to depth were 9.3 kg/m4 and 0.5 MPa/m, respectively. The shallow sites possessed a porous structure with 14.5 % more big pores (>1 mm). The pore structure followed fractal patterns, and the fractal dimensions increased slightly with depth. Our findings not only deepen the understandings in slurry sedimentation and the consequences of engineering properties, but also narrow the knowledge gaps between in-lab tests and in-situ applications for grouting construction.

Study on the working performance and microscopic mechanism of high-performance grouting material (HPGM) reinforced dense fine sand layer

To address the challenges of small diffusion radius, low early strength and long setting time of traditional cement grout in dense fine sand layer, based on the synergistic mechanism, a novel high-performance grouting material (HPGM) was developed using ground granulated blast-furnace slag (GGBS), ultra-fine fly ash (UFFA), and ultra-fine Portland cement (UFPC) as raw materials. Firstly, Laboratory experiments were conducted to investigate the working performance of HPGM under varying proportions. Secondly, based on the self-designed advanced small pipe grouting full-scale test device, the diffusion performance and reinforcement characteristics of HPGM under varying proportions were analyzed. Finally, the XRD and SEM testing methods were employed to elucidated the hydration mechanism of the HPGM. The test results indicate that as the mass ratio of GGBS to UFFA decreases, there is a gradual increase in hardening rate, fluidity and setting time of HPGM. Additionally, the unconfined compressive strength (UCS) initially increase before decreasing. Furthermore, with the decreased mass ratio of GGBS to UFFA, the HPGM diffused in dense fine sand layer through compaction-splitting, permeation-splitting, and splitting grouting processes. The hydration products of the HPGM primarily consist of C(-A)-S-H, AFt, and Ca(OH)2, when the mass ratio of GGBS to UFFA falls within the range of 4:2–3:3, the UFFA facilitates the AFt hydration products in significant quantities. Its cementation and filling effect lead to the formation of a dense microstructure in the soil, resulting in a substantial reduction in permeability coefficient and a marked increase in UCS. The research findings can offer high-performance grouting material for underground engineering construction while also presenting innovative ideas for resource utilization from solid wastes like GGBS and UFFA.

Use of rise husks to improve the efficiency of MICP-based soil improvement technique

Biogrouting has been identified as the best alternative approach for the conventional cement and chemical grouts. Among the various types of biogrouting techniques, microbial induced carbonate precipitation (MICP) has been recently recognized as a promising pathway for producing biogrout material, hence densifying the weak soils. In MICP, calcium carbonate (CaCO3) biocement is produced through biochemical reactions induced by the urease enzyme. The efficiency and productivity of MICP can be further improved by introducing various additives, including fibers, organic polymers, powders, waste materials, etc. In this research, rice husk was sustainably incorporated into the MICP process, and (i) the effect of the rice husk content, (ii) the concentration of the cementation solution and (iii) the treatment time on the unconfined compressive strength (UCS) of the sandy soil were investigated at the laboratory-scale. Cementation solutions with higher concentrations exhibited a higher UCS values than solutions with lower concentrations. Interestingly, the content of rice husk had a marked influence on the UCS, and the optimum rice husk content was 15%. Compared to that of the control sample (0% rice husk), a threefold greater UCS was obtained for 15% of the rice husk content sample. The outcomes further suggested that longer treatment with lower concentration of cementation solution was the best combination for achieving effective cementation within the sand matrix. Rice husk acted as the template for CaCO3 crystals to nucleate while promoting the efficient formation of CaCO3, indicating that the rice husk is an excellent additive to improve the efficiency of the MICP biocementation in a sustainable way.

Investigation on the pore size characteristics and mechanical properties of grouting materials scoured by flow water

Investigating the pore size characteristics and mechanical properties of the stone bodies formed by residual grout is crucial for understanding the authentic permeability and load-bearing capacity of grouting materials after being scoured by water flow. In this study, the pore size distribution, porosity, uniaxial compressive strength (UCS), and elastic modulus (E) of stone bodies formed by residual grout from polyacrylate latex-modified cement grouting material (PLMC) were systematically investigated, and pure cement grout (PC) as a control group. First, scouring tests were conducted on grouting materials with various water-to-cement ratios (w/c, 0.6–0.8) and polymer-cement ratios (p/c, 0–0.2) under different flow velocities (0–1 m/s). Subsequently, the pore size characteristics of stone bodies formed by residual grout under various conditions were studied via nuclear magnetic resonance test. Finally, the uniaxial compression tests were conducted to investigate the impact of water scouring on the mechanical properties of grouting materials, and the relationship between pore size characteristics and macro mechanical responses was analyzed. Results show that the stone bodies formed by residual grout compared to the non-scoured state develop mesopores and macropores, and the number of micropores also increased significantly. This porosity escalation results in a reduction in UCS and E. When the flow velocity reaches 1 m/s, the porosity of PLMC with w/c = 0.8 increases by 2.95 %, while UCS decreases by 14.6 % and E decreases by 37.4 %. PC demonstrates more pronounced changes, with a porosity increase of 7.01 %, UCS decreases by 32.9 %, and E decreases by 41.5 %. With the rise in w/c, the deterioration of pore structure and mechanical properties of the stone bodies formed by residual grout is more significant compared to the non-scoured state. Increasing p/c can mitigate the deterioration of the pore structure and mechanical properties. The findings provide meaningful guidance for the grouting reinforcement under dynamic water conditions.

Assessment of Semi-Flexible Pavement Using Styrene-Butadiene Emulsion Modified Cement Grout

Semi-flexible pavement (SFP) is a type of road surface that combines open-graded asphalt concrete with cement grout for wearing courses containing 18 to 28% air voids. This study investigates the effectiveness of two types of cement grouts using modified styrene-butadiene emulsions, Sika Latex and Sika Latex TH, with varying amounts ranging from 4.5% to 7.5% and 7.5% to 9%, respectively. The goal of the paper is to determine the appropriated type of styrene-butadiene emulsion type for SFP. To create the SFP, the selected grout and Vinkems Asphalsol grout with a water-cement ratio of 0.45 were poured into the asphalt structure, resulting in an SFP with 22.8% air voids. Additionally, several experiments were conducted to evaluate the effectiveness of SFP. These experiments included the Marshall stability test, indirect tensile strength test, and resilient modulus test. The study results showed that Sika Latex 6.5% and Sika Latex TH 9% had good properties for use in SFP.

Diffusion properties and cementitious characteristics of ultrafine cement slurry in coral sand

Investigating the infiltration, diffusion and permeation of cement grouting materials in coral sand and the effects of grouting reinforcement measures can provide scientific support for coral sand foundation treatment, building settlement adjustment, and coastal geological disaster prevention and control. Permeation grouting tests were conducted on coral sand, and the effects of the water–cement ratio (w/c), permeability coefficient of coral sand (PCCS), and grouting pressure on the diffusion distance of the slurry, uniaxial compressive strength (UCS), and relative permeability coefficient (RPC) of the grouting cementitious body were analysed. In addition, the change trends in the slurry diffusion distance and slurry pressure was described, and the characteristics of the grouting cementitious body were analysed from three perspectives: UCS, RPC, and microstructure. The results showed that the slurry pressure increases nonlinearly with increasing grouting time and decreases nonlinearly with increasing slurry diffusion distance; additionally, UCS decreases with increasing slurry diffusion distance, with an “S”-shaped curve that is first concave and then convex, with an inflection point near L = 50 cm.

Optimal development and performance evaluation of electrolytic graphene oxide synergistic all-solid waste cementitious grouting material

The low-carbon and friendly alkali-activated cementitious (AACM) grouting material has a broad application potential in the field of grouting engineering due to its excellent workability and higher early strength and is expected to replace cement grouting material in the future. In this study, an AACM grouting material using electrolytic graphene oxide (EGO) synergistic ground granulated blast-furnace slag (GGBS)-fly ash (FA)-rice husk ash (RHA) solid waste was proposed. The optimal ratio was 0.025 % EGO, 8.13 % FA, 26.6 % RHA, and 65.27 % GGBS, which determined by the Analytic Hierarchy Process (AHP), Entropy Weight Method (EWP), and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) methods. A systematic evaluation of the mechanical properties and impermeability of the proposed AACM grouting material was conducted by macro experiments (compressive strength, flexural strength and permeability) and micro experiments (XRD, SEM-EDS, Fourier Transform Infrared Spectrometer (FTIR) and Thermogravimetry Analysis (TG)). The results show that the increment of compressive strength and flexural strength for AACM grouting material with 0.025 % EGO compared to the cement water-glass grouting material were 161.2 % and 2.9 %, respectively, at 7-day. While the permeability coefficient compared to AACM grouting material without EGO decreased by 43.9 %. The XRD results show that the EGO reduced the intensity of AACM grouting material diffraction peaks, and FTIR analysis reveals that EGO increased the visibility of O-C-O characteristic peaks. These confirmed that EGO could enhance the degree of alkali activation reaction. The TG results indicate that the addition of EGO promoted the formation of carbonates, which strengthen the mechanical properties of AACM grouting material. The SEM-EDS results demonstrate that EGO increased the Ca/Si ratio, promoted the formation of highly polymerized hydration products.

Robust prediction models for flow and compressive strength of sustainable cement grouts for grouted macadam pavement using RSM

This study investigates the utilization of pumice stone ash in cementitious grouts for grouted macadam pavement, aiming to enhance flowability and compressive strength. Partial replacement of ordinary Portland cement (OPC) with varying percentages (5–20 %) of powdered pumice stone (PPS) ash was explored, alongside adjustments in water-to-cement (w/c) ratios. Experimental assessments, including flowability tests and compressive strength evaluations, were conducted on fresh and hardened grouts. Response surface methodology (RSM) and ANOVA analysis were employed to analyze the relationship between pumice stone ash content, w/c ratio, flow, and compressive strength. The results show that increasing the PPS content from 0 % to 20 % led to an increase in flow time from 23.6 to 34 seconds at a 0.3 w/c ratio, from 9 to 19 seconds at a 0.35 w/c ratio, and from 7 to 14 seconds at a 0.40 w/c ratio: indicating reduced flowability of the grouts. The 7-day compressive strength increased by approximately 2–17 % when 5–15 % of the cement was replaced with PPS, but a reduction occurred at 20 % PPS. Similarly, the 28-day compressive strength increased by about 4–23 % with 5–15 % PPS, while 20 % PPS led to a decrease in strength. The results highlight specific combinations of pumice stone ash content and w/c ratios, particularly 10 % PPS at 0.35 w/c and 15 % PPS at both 0.35 and 0.40 w/c, that meet grouted macadam standards, balancing flowability and strength. Fit statistics demonstrate the reliability of the predictive model. Optimization aims to maximize pumice stone ash content and w/c ratio, with graphical representation indicating an optimal composition at 17.25 % PPS and 0.35 w/c ratio for efficient grouted macadam construction. Additionally, Significant contribution towards sustainability can be achieved by replacing cement with pumice stone ash in pavement construction.

Performance and microstructural characterization of fiber-reinforced cement-based grout incorporating waste tailing sand and fly ash

A fiber-reinforced cement and tailing sand-based grout (FRCTG) was proposed to improve the utilization of solid waste in construction. Different grout specimens were prepared using various proportions of ordinary Portland cement, iron tailing sand (ITS), fly ash (FA), basalt fibers (BFs), and water as raw materials. Used single-factor test, orthogonal test and artificial neural network model that provided a comparative analysis of the change in the rheological and mechanical properties of different grout mixes according to their component ratios. Furthermore, microscopic characterization techniques were used to reveal the intrinsic physicochemical mechanisms underlying the structural evolution of the considered grouting materials. The results indicate that ITS significantly increases the rheological properties of the grouting material. The maximum strength of the grouting material is achieved when the length of BF is 6 mm and the dosage is 0.2 %. An 8 % dosage of FA can effectively improve the rheological properties of the grouting material and enhance its flexural strength. Microscopic tests reveal that SiO2 in ITS exists in the form of quartz with low reactivity, thereby inhibiting the hydration reaction of the binder material. Different distribution patterns allow BF to serve both as reinforcement for the matrix and as a framework for hydration products, effectively enhancing the density between the BF and the surrounding matrix. The surface of FA is covered in layers by hydration products, forming a chain-like structure that improves bonding strength with the material. The results of this research offer a high-performance, low-cost, and environmentally friendly grouting material for construction grouting projects, which is of significant importance for promoting innovation in comprehensive utilization of solid waste.

Waste-based panels with cement grout as an infill material for composite railway sleepers

The development of high performance and eco-friendly composite railway sleepers at a reasonable price is a great challenge for composite railway sleeper manufacturers. The study proposed a railway sleeper concept based on high-performance fibre composites and low-cost waste-based materials to overcome this challenge. In this concept, thin hollow composite tubes are filled with high volume waste-based panels, which are bonded together with cement grout. This study examined the effect of cement grout, grout thickness, panel types, and surface preparation of the panels on the bond behaviour between the panels and cement grout. It also investigated the bending behaviour of manufactured railway sleepers by evaluating the effects of filling hollow tubes, the orientation of the infill panels, and the types of infill materials. Results indicate that the proposed concept has a high potential for development of high performance and eco-friendly composite railway sleepers at a competitive price due to the incorporation of high volume of waste materials. The results of the study will serve as a guide to the manufacture and design of composite railway sleepers.

Ultimate Capacity and Load Transfer Mechanism of Ground Anchors in Granular Soils: State-of-the-Art

The grouted ground anchor is the most used geotechnical element to transfer the tension load from the superstructure or the soil mass in front of the potential failure surface (active zone) to a deeper, efficient soil layer for its reliability and feasibility. It was originally constructed by inserting the tendon, usually a steel strand, into an already drilled borehole filled with cement grout. It was successfully used in the Cheurfas dam in Algeria in (1934). According to the load transfer mechanism, there are two types of ground anchors: tension-type and compression-type. The names of these two types of anchors refer to the developed stresses in the grouted body. The present work presents a literature survey about the load transfer mechanism for both types of anchors: tension and compression embedded in granular soil. Many factors affecting the load transfer mechanism have been reviewed. The main factor affecting the load transfer mechanism is the confining pressure of the borehole. The recently developed methods of estimating the ultimate pullout capacity of the anchor have been reviewed and discussed.