With the increase of cement output, the demand for cement expansion agents increases, and composite expansion agents have become the development trend. The purpose of this study is to study the microscopic change process and expansion effect of calci...
Cement-free concrete has a superior physical performance, such as in its strength and durability, compared to OPC concrete; however, it has the disadvantage of large shrinkage. Large shrinkage can cause cracks due to shrinkage stress in the long term...
In order to explore the intrinsic relationship between the expansion and strength of cementitious materials with CaO-based expansion agent (CEA), the effects of CEA on the expansion rate, strength, microstructure, and hydration products of cement pas...
Using the volume expansion generated by the hydration of the MgO expansive agent to compensate for the shrinkage deformation of concrete is considered to be an effective measure to prevent concrete shrinkage and cracking. Existing studies have mainly...
This is an experimental study on the development of a low-carbon, eco-friendly cement containing a calcium sulfoaluminate expansive agent (CSAe), slag, and silica fume (SF). The cement to be developed has a low water/binder ratio (w/b) of 0.5 and is...
Understanding the hydration kinetics of cement paste is essential for adjusting the early-age performance of concrete. Low-field nuclear magnetic resonance (LF-NMR) has emerged as an innovative technique to evaluate cement hydration progress by analy...
Traditional expansive agents often fail to address early-stage cracking issues of grouting. A plastic expansive agent (PEA) can generate evenly distributed and closely packed microbubbles in the cement-basted grouting materials during the grout&rsquo...
Shrinkage of concrete during hardening is a serious problem in attempts to maintain the integrity of concrete structures. One of the methods of combating shrinkage is compensating for it using an expansive agent. The purpose of this work is to develo...
MgO expansive agent (MEA) has the potential to meet the shrinkage compensation demands for concrete in different types of structures due to its designable reactivity and expansion properties. This study investigated the impact of three types of MEAs...
In China, MgO-based expansive agent (MEA) has been used for concrete shrinkage compensation and cracking control for over 40 years. The expansive behavior of MEA in cementitious materials could be manipulated to some extent by adjusting the calcinati...
The cement industry’s intricate production process, including kiln heating and fossil fuel use, contributes 5–8% of global CO2 emissions, marking it as a significant carbon emitter in construction. This study focuses on quantifying CO2 ca...
In response to the issues of concentrated early-stage hydration heat and significant self-shrinkage in high-strength cementitious grouting materials at low water-to-binder ratios, improvements were achieved by co-blending granulated blast furnace sla...
In this study, the characteristics of grout mixed with charcoal as an expansive agent were examined to reduce the pre-hardening shrinkage of cementitious materials. This study compared and reviewed the application of CSA, a conventional expansive age...
The physical and mechanical properties of grouting materials greatly affect the friction resistance and the bearing performance of a non-soil-squeezing PHC pipe pile. Orthogonal tests for four factors at five levels were carried out to optimize the p...
Due to post-cementing hydraulic fracturing and other operational stresses, inadequate mechanical properties or suboptimal design of the cement sheath can lead to tensile failure and microcrack development, compromising both hydrocarbon recovery and w...
The addition of expansive agents could overcome the main disadvantages of raw concrete including high brittleness and low tensile strength. Few studies have investigated the early hydration kinetics of expansive cementitious binders, though the findi...
Superfine cement is widely used in building reinforcement and repair, special concrete manufacturing, and environmental protection engineering due to its high toughness, high durability, good bonding strength, and environmental friendliness. However,...
To promote the application of MgO-type expansive agents (MEAs), the expansion stresses produced by compacted MEAs with different activities cured in water at 40 °C were measured using a self-designed expansion stress test apparatus. Based on thes...
In mass concrete, shrinkage resulting from temperature drop and drying leads to cracking, which can seriously affect the strength and durability of cement-based materials. Fortunately, expansion agents can deter or prevent these effects, especially M...
Many scholars are concerned about the effect of nano-MgO as an expansion agent on the performance of cement-based materials at an early age, but over a long period less attention is paid to expansion stability and mechanical properties. This article...
This study aims to study the influence of a lightly burned magnesium oxide (LBMO) expansion agent on the rheological properties (the slump flow, plastic viscosity and variation of shear stress) of cement-based materials. Four different mass contents...
This review provides the hydration and volume expansion mechanism of expansive materials, with the goal of utilizing them in the development of sustainable mining methods. The main focus of the review will be the newly developed non-destructible rock...
To address the severe damage caused by voids beneath cement concrete pavement slabs, which compromise pavement performance and lifespan, there is an urgent need to develop an economical and efficient grouting material for slab void repair. This study...
To solve the problem of the field application of downhole hydraulic fracturing technology due to the difficulty in sealing holes, this study analyzes the influence of special cement, expansion agents, stabilizers, and fiber material on basic properti...
This study investigates the effects of surface roughness and interfacial agents on the bond performance of geopolymer–concrete composites (GCCs). Firstly, cement concrete substrates with four surface roughness conditions, including cast surface...
In order to study the cement–industrial waste-based synergistic curing of silt soil, orthogonal design tests were used to prepare a new curing agent using cement, fly ash, blast furnace slag, and phosphogypsum as curing materials. In order to e...
Bridges’ expansion joints are prone to damage during operation, and repairing them often requires interruption of traffic, the impact of which can be minimized by using fast-hardening and early-strength expansion joint materials. In this study,...
The shrinkage of core concrete during construction is the key reason for the separation of steel pipes and core concrete. Utilizing expansive agents during cement hydration is one of the main techniques to prevent voids between steel pipes and core c...
This study develops a rapid-hardening and high-fluidity ultra-high-performance cement (UHPC)-based grout by incorporating calcium sulfoaluminate (CSA) cement as an early strength component, along with steel and wollastonite fibers as hybrid reinforce...
This paper studies the influence of assembly unit of expansive agents (CaO and calcium sulphoaluminate) on the limited and free compressive strengths, the limited expansion rate, carbonation resistance, chloride ion penetration resistance and corrosi...
After removing the mold from the secondary lining concrete of a tunnel, problems such as honeycomb and hemp surface easily occur. To obtain self-compacting fair-faced concrete (SCFFC) that can meet strength requirements and effectively solve the abov...
At present, it is known that when there is clay in concrete, polycarboxylates (PCE) will preferably adsorb in the clay, so that PCE cannot be fully combined with cement particles, which reduces the workability of the cement slurry. In this paper, a n...
A large number of binder ingredients such as cement and active mineral admixtures are used in the preparation of high-strength concrete, and the water:binder ratio is extremely low. This leads to a large amount of shrinkage of concrete at the early s...
This paper addresses the issues of insufficient expansion force, low early strength (1-day compressive strength < 1.5 MPa), and poor toughness (flexural strength < 0.8 MPa) in traditional chemical foamed cement used for road grouting repair. By...
Heat-curing processes are often used to ensure the production rate of precast concrete elements, as this process increases the early strength of the material. However, the increase in curing temperature can negatively affect the final mechanical prop...
This paper presents an approach to predicting the intrinsic self-healing in concrete using a hybrid genetic algorithm–artificial neural network (GA–ANN). A genetic algorithm was implemented in the network as a stochastic optimizing tool for the initi...
This paper develops foamed mixture lightweight soil (FMLS) using dredged soil for ecological floating landscapes applications, focusing on key performance indices including dry density, compressive strength, splitting tensile strength, water absorpti...
In this study, the shrinkage and durability of environmental load-reducing fiber-reinforced polymer cement mortar (FRPCM) were examined by using silicone oil. The results indicated that the shrinkage can be greatly reduced by adding silicone oil. How...
Aeolian sand is the primary geological material for construction in desert regions, and its stabilization with industrial solid wastes-based geopolymer (ISWG) provides an eco-friendly treatment replacing cement. This study comparatively investigated...
The disposal of coal mine solid waste has always been a challenge in the coal mining production process, and the research and development of low-cost and high-performance filling materials is a prerequisite for achieving large-scale disposal of coal...
The suitability of applying shrinkage reducing additives in alkali activated coal gangue-slag composites is discussed in this study. The effect of sulphoaluminate cement (SAC), high performance concrete expansion agent (HCSA) and U-type expansion age...
The problem needs to be solved about stability control of small coal pillars along goaf in the coal mining process. In this paper, the effects of water reducer, accelerator and expansion agent on the fluidity, setting time, expansion ratio and stone...
The cemented backfill (CB) utilizing coal gangue (CG) and fly ash (FA) is widely applied in coal mines. However, the bleeding and shrinkage of CB leads to insufficient contact with surrounding rock, which is not beneficial for controlling roof subsid...
In this paper, a tetramethylammonium hydroxide (TMAH) solution and homemade cement without alkali were used to eliminate the influence of the alkali-silica reaction (ASR) on the expansion of dolomitic rocks, and a NaOH solution was used as a comparis...
To solve the problems of brittleness, high cost, and the complicated construction process of traditional filling materials for filling abandoned roadways, various aspects of the physical and mechanical properties of the materials were studied using l...
The Baikouquan Oilfield is entering middle and later periods of development. Casing failure, caused by the quality of cementing and casing corrosion, affects the normal production of the well. The number of wells in this situation has been increasing...
Using ultrafine silicate cement as the cementitious material, and admixtures such as expansion agent, rapid-setting agent and water reducer as additives, a new type of composite grouting material with high early strength and high toughness was obtain...
This study investigated the effect of water-washed municipal solid waste incineration fly ash (MSWI FA) as an admixture on the performance of dry mixed mortar and used X-ray diffraction (XRD) and scanning electron microscope (SEM) detection methods t...
The expected lifespan of cement-based materials, particularly concrete, is at least 50 years. Changes in the pore structure of the material need to be considered due to external influences and associated transport processes. The expansion behaviour o...
Fly-ash-based bubble lightweight soil is widely used due to its environmental friendliness, load reduction, ease of construction, and low costs. In this study, 41 sets of 28 d compressive strength data on lightweight soils with different water–...
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