Cement Grout Research Articles (Page 1)

Open caisson shafts are widely used to create underground spaces. During construction, the caisson is sunk into the ground under its own weight, often aided by a bentonite-filled annulus to reduce friction with the surrounding soil. After sinking, cementitious grout is typically injected into the annulus to displace the bentonite and re-establish friction at the soil–structure interface. Non-uniform grout coverage, caused by viscous fingering (VF), poses a significant risk during this process. VF occurs when a less viscous fluid (grout) is injected into a more viscous fluid (bentonite), leading to an unstable displacement front and uneven distribution of the injected fluid. This study addresses this issue by developing a model using established VF principles and the Sisko rheological model to produce a novel closed-form equation, which is validated using data from tests conducted using a custom Hele-Shaw-type apparatus. The model relies on readily obtainable parameters, making it practical for on-site use, where grout injection is typically contractor-led. The developed model is shown to accurately predict the uniformity of final grout distribution, providing a basis for improved caisson design and construction.

An integrated statistical–graphical framework is introduced for designing sustainable cement grout mixes that incorporate polyethylene terephthalate (PET) waste and supplementary cementitious materials (SCMs) for semi-flexible pavement applications. A correlated multivariate linear mixed-effects model employs additive log-ratio transformations of PET and SCM proportions (fly ash or silica fume relative to cement) to predict 1-day, 7-day, and 28-day compressive strengths and 28-day flexural strength within a single unified framework. This approach quantifies both the systematic strength penalty of PET substitution and the benefits of SCM additions. The model results demonstrate high random-intercept correlations, substantial reductions in the Akaike information criterion (AIC) and root mean squared error (RMSE) compared to a null model, and marginal and conditional coefficient of determination (R2) values of 0.96 and 0.99, respectively, confirming major capture of the variance in the mechanical response. Complementary ternary plots visualize predicted 28-day performance across the cement–PET–SCM compositional space. These plots reveal that zero-PET formulations along the cement–binder edge achieve maximum strengths, with both fly ash and silica fume maximizing compressive and flexural strengths and any PET addition uniformly degrading performance. By combining rigorous compositional modeling with intuitive visualization, the proposed framework offers quantitative rigor, practical mix design guidelines, and a scalable protocol for optimizing sustainable grout formulations and informing future exploration of alternative fillers, flow regimes, and durability assessments.

Root-inspired ground anchors are an emergent bio-inspired geotechnical ground anchoring technology leveraging the pullout resistance efficiency of fibrous plant root systems. These anchors are a technologically feasible means to construct root-like anchor geometries in-situ using conventional ground anchor construction techniques and equipment: a ferrous linkage mechanism alters its configuration in-situ from cylindrical to root-like and remains fixed in the latter configuration by cured cement grout. This technology currently lacks a means to estimate forces on the linkage mechanism during in-situ actuation, and thus, mechanism design and size limitations are poorly understood. A reliability-based design procedure and Monte-Carlo simulation software are presented which implement an analytical estimate of the forces on root-inspired ground anchors during actuation in-situ and an analytical pullout capacity prediction method. Design examples are presented along with software outputs and discussion of the assumptions and limitations of the methodology.

This study investigates the potential usage of biowaste (i.e., bagasse ash) in cementitious grouts for semi-flexible pavement applications. Cementitious grouts were prepared by partially replacing cement with bagasse ash (5%, 10%, 15% and 20%) and at w/c ratios of 0.30 to 0.40. Flow cone apparatus was used to determine the flow properties of fresh cementitious grouts. The hardened specimens of cementitious grouts also were tested for compressive strength at curing ages of 7 and 28 days. Moreover, response surface methodology (RSM) was used to analyze the relationships between independent/input variables (bagasse ash and w/c ratio) and dependent/output variables (flow and compressive strength). Compressive strength tests revealed that 7-day strength ranged from 27 MPa to 41 MPa, while 28-day strength ranged from 35 MPa to 65 MPa. Results indicate that bagasse ash significantly influences the flowability and compressive strength of the cementitious grouts, with optimal performance achieved at a 15% replacement level and a 0.35 w/c ratio. The optimal combination achieved a flow value of 16 seconds, a 7-day compressive strength of 32 MPa, and a 28-day compressive strength of 49 MPa. Response surface methodology (RSM) confirmed these results, identifying an optimized mix composition of 16% bagasse ash and a 0.35 w/c ratio. The findings demonstrate the potential of bagasse ash as a sustainable alternative to cement, contributing to reduced environmental impact and improved material performance in semi-flexible pavements.

Semi-flexible pavement (SFP) relies primarily on the properties of cementitious grouting material (CGM), which plays a crucial role in providing durability and crack resistance. This paper investigates the performance of CGMs containing recycled waste glass (RWG) as a replacement to fine granite aggregate (FGA) and their effect on SFP mixtures. Two high-fluidity glass-cementitious grouts (Glcement grouts) were developed and tested at five RWG replacement levels (0%, 30%, 50%, 70%, and 100%). The results indicated that CGM with 70% RWG provided the most balanced performance, with a flowability of 11.8 s, low drying shrinkage (0.04%), and water absorption not exceeding 1.9%. The mechanical properties were significantly enhanced, achieving a high compressive strength of 121.9 MPa and a high flexural strength of 13.9 MPa. Microstructural analysis confirmed a refined interfacial transition zone with low porosity (5.36%), contributing to superior durability. Furthermore, the SFP mixture injected with Glcement exhibited high mechanical performance, attributed to improved interlocking within voids. In conclusion, replacing FGA with RWG in CGM optimizes both mechanical and durability properties, promoting sustainable and low-carbon pavement construction.

Due to the increasing volume of traffic on the world's highways, researchers have been searching for new composite techniques and methods to develop durable and cost-effective pavement structures. The semi-rigid pavement is a composite pavement consisting of a porous asphalt mix with air voids between 25 and 30% and a high-fluidity cementitious grout. In this study, different cementitious grout mixes were prepared. Then a porous asphalt mix with almost 30% air void content was designed. After evaluating the workability, mechanical strength, and volume stability of the prepared grout mixes, the most suitable mix is proposed to fill the voids in the porous asphalt mix. Finally, the prepared semi-rigid pavement specimens were subjected to various tests to evaluate the performance characteristics of the designed pavement. The research concludes that the grout mixture ratio proposed in this study has good grouting ability and the semi-rigid pavement has superior performance characteristics.

Semi-flexible pavement (SFP), a hybrid pavement system that combines open-graded asphalt with cementitious grout, offers enhanced durability, load-bearing capacity, and resistance to rutting compared to conventional pavement systems. However, the environmental impact of cement usage in grout formulations remains a significant concern due to its high carbon footprint. This study explores the feasibility of partially replacing ordinary Portland cement with industrial by-products, fly ash (FA) and silica fume (SF), in cement grouts for SFP applications. Grout mixtures with 5% and 10% replacements of FA and SF were prepared and evaluated for flowability, compressive strength (at 1, 7, and 28 days), and flexural strength (at 28 days). The study found that fly ash (FA) improves grout flow and long-term compressive strength, with 10% FA achieving a 16% increase at 28 days. Silica fume (SF) enhances both early and overall strength but reduces flowability at higher doses. Both additives improved flexural strength, with 5% FA showing a 28% increase over the target. Based on optimal flow (11–16 seconds) and compressive strength (60 MPa), the best performance was observed with 10% FA and 5% SF. These results suggest that FA and SF can serve as effective and sustainable partial replacements for cement, maintaining or enhancing mechanical performance while lowering environmental impact. This makes them suitable for use in semi-flexible pavement (SFP) applications, contributing to both durability and sustainability goals.

Effect of Cellulose Ether and Nanoclay on Rheology and Segregation Resistance of Cementitious Grouts for Post-Tensioning Applications

The effect of PCNPs on the rheological properties of cement grout at high temperatures

Abstract A semi-flexible pavement (SFP) is formed from two materials of different characteristics, including a porous asphalt mixture (PAM) with flexible properties and hardened cement with rigid properties. Grouting materials and PAM’s porosity play an essential role in SFP, resulting in high-performance pavement. The purpose of the study is to review the authors’ aspects of SFP, focusing on selecting the data to analyze the relationships between factors affecting the characteristics of SFP, materials, technical requirements, and design methods. The study concludes with the gaps in the field, such as the interface material, porosity of PAM, application of AI in analyzing and predicting the properties of SFP, and recycled material using grout cement and PAM. This review provides researchers with a thorough understanding of the design process of SFP and the continuous development of the material to apply on the pavement. Additionally, various relationships related to SFP, grouting materials, and PAM are illustrated through figures, tables, and equations for better comprehension.

A reliable bond between cementitious grout and deformed steel bars is essential for effective load transfer and composite action. With the growing use of cementitious grout jackets for strengthening RC structures in cold regions, a comprehensive understanding of their bond behavior is critical for evaluating the load-bearing capacity and performance evolution of strengthened structures under freeze–thaw conditions. Accordingly, establishing the bond stress–slip model between cementitious grout and deformed steel bars is of great importance for both theoretical analysis and numerical simulation. This study conducts local bond–slip tests to examine the effects of steel bar diameter and cover thickness on bond performance under freeze–thaw cycles. The results reveal that as the c/d ratio decreases, the failure mode shifts from pullout to splitting failure. Specimens exhibiting pullout failure show significantly higher peak bond strength and slip compared to those with splitting failure. The peak bond strength decreases rapidly with increasing freeze–thaw cycles, while higher c/d ratios mitigate the rate of degradation. After 240 freeze–thaw cycles, the peak bond strength is reduced by 24.6 to 51.9%. Peak slip remains relatively unaffected by freeze–thaw cycles and is primarily influenced by rib spacing and c/d. To account for the combined influence of c/d and stirrup ratio, a confinement coefficient K is introduced. Based on this, a bond–slip model incorporating freeze–thaw effects and confinement is proposed, and its reliability is validated.

Abstract In this study, the expressions of linear function, power function, logarithmic function, exponential function, and quadratic function were adopted to carry out regression analysis on the test data obtained from a HT225‐A standard rebound hammer with nominal impact energy of 2.207 J and a HT450‐A high‐strength rebound hammer with nominal impact energy of 4.500 J. The aim of the study is to develop a dedicated rebound strength measurement curve for Class IV cementitious grout, which is commonly used in structural reinforcement applications. Four strength grades of grout (A40, A50, A60, and A70) were tested across six curing ages (1, 3, 7, 14, 28, and 60 days), with six cubic specimens prepared for each age. Results showed that the power function using data from the standard rebound hammer achieved the highest accuracy, with a correlation coefficient of R2 = 0.97, and met the required error limits. The resulting curve is applicable for compressive strength estimation of external grout brands as well. Furthermore, finite element analysis in ABAQUS was used to evaluate the effects of key boundary conditions. Simulations revealed that the impact spacing should be no less than 20 mm to avoid interference, grout thickness should be greater than 30 mm to ensure accuracy, and error reduced from 30.67% at 20 mm to 3.27% at 30 mm. The distance from the specimen edge should be greater than 20 mm, with the error decreased from 71.91% at 0 mm to negligible levels at 20 mm. Corresponding conversion factors for non‐ideal conditions were also proposed. These findings provide practical guidance for the reliable field application of the rebound method in grout strength assessment.

Effects of lithium carbonate and nano-calcium carbonate on the hydration and properties of calcium sulfoaluminate cementitious grout

Seismic behavior of reinforced concrete columns strengthened with cementitious grout jacket

Fresh, mechanical and durability properties of sustainable cement grouts incorporating dredged materials from UAE dams

Optimization of mix proportion of super-early-strength cement grouting material and experimental study on its working performance

Tunneling in structurally complex, tectonically active regions such as southwest China poses significant environmental risks to groundwater, especially in heterogeneous karst fault systems where conventional prediction methods often fail. This study innovatively coupled MODFLOW’s STREAM package (for simulating karst conduit networks) and DRAIN package (for tunnel inflow prediction) within a 3D groundwater model to assess hydrogeological impacts in complex mountainous terrain. The simulations show that an uncased tunnel lining causes significant groundwater changes under natural conditions, with predicted inflows reaching 34,736 m3/d. Conventional cement grouting (permeability: 1 × 10−5 cm/s; thickness: 10 m) mitigates the effects considerably and reduces the inflows in the tunnel sections by 27–97%. Microfine cement grouting (5 × 10−6 cm/s; 10 m thickness) further improves performance by achieving a 49–98% reduction in inflows and limiting the reduction in spring discharge to ≤13.28%. These results establish a valid theoretical framework for predicting groundwater impacts in heterogeneous terrain and demonstrate that targeted seepage control—particularly grouting with microfine cement—effectively protects groundwater-dependent ecosystems during infrastructure development.

With rising global temperatures, roads in the permafrost regions of the Qinghai–Tibet Plateau are exhibiting issues such as subsidence, water accumulation alongside the roads and in their foundations, and ongoing permafrost degradation. Among these issues, water accumulation has emerged as a prominent challenge in road management. In this study, sodium-based-bentonite-modified cementitious waterproof grouting materials were prepared and utilized as functional barrier layers. The rheological properties, mechanical strength, flowability, and setting time of the materials were tested under different sodium bentonite dosages. The feasibility of the application of these materials was evaluated, accounting for the evolution of pressure, flow rate, and diffusion distance of permafrost subgrades over different time scales when the materials were applied as functional barrier layers. The results indicate that, when used as a functional barrier layer, the modified cement-based grouting material exhibits a fluidity that meets the upper limit of grouting requirements, with a controllable setting time. Both compressive strength and apparent viscosity rise with the addition of sodium-based bentonite (Na-bentonite). Notably, an appropriate viscosity range of 0.35–0.50 Pa·s was found to effectively resist groundwater erosion while satisfying the critical performance requirements for grouting applications, demonstrating excellent applicability. In the field grouting test, the effects of grouting pressure and flow rate over different time scales on soil cracking, spreading distance, and the crack-filling process were further analyzed. Based on these findings, a technical solution using a new type of subgrade treatment material (functional barrier layer) was proposed, providing a reference for related theoretical research and engineering practice.

The increasing depth of coal mine construction has led to complex geological conditions involving high ground stress and elevated groundwater levels, presenting new challenges for water-sealing technologies in rock microfissure grouting. This study investigates ultrafine cement grouting in microfissures through systematic analysis of slurry properties and grouting simulations. Through systematic analysis of ultrafine cement grout performance across water–cement (W/C) ratios, this study establishes optimal injectable mix proportions. Through dedicated molds, sandstone-like microfissures with 0.2 mm apertures and controlled roughness (JRC = 0–2, 4–6, 10–12) were fabricated, and instrumented with fiber Bragg grating (FBG) sensors for real-time strain monitoring. Triaxial stress-permeation experiments under 6 and 7 MPa confining pressures quantify the coupled effects of fissure roughness, grouting pressure, and confining stress on volumetric flow rate and fissure deformation. Key findings include: (1) Slurry viscosity decreased monotonically with higher W/C ratios, while bleeding rate exhibited a proportional increase. At a W/C ratio = 1.6, the 2 h bleeding rate reached 7.8%, categorizing the slurry as unstable. (2) Experimental results demonstrate that increased surface roughness significantly enhances particle deposition–aggregation phenomena at grouting inlets, thereby reducing the success rate of grouting simulations. (3) The volumetric flow rate of ultrafine cement grout decreases with elevated roughness but increases proportionally with applied grouting pressure. (4) Under identical grouting pressure conditions, the relative variation in strain values among measurement points becomes more pronounced with increasing roughness of the specimen’s microfissures. This research resolves critical challenges in material selection, injectability, and seepage–deformation mechanisms for microfissure grouting, establishing that the W/C ratio governs grout performance while surface roughness dictates grouting efficacy. These findings provide theoretical guidance for water-blocking grouting engineering in microfissures.

Insights into the impact of acetic acid on particle refinement, hydration, and strength development in cementitious grouts