Cement Agent Research Articles

The impact of mono-ethylene glycol on ordinary Portland cement: Exploring grindability, workability, hydration, and mechanical properties

Glycol-based components are commonly used as grinding agents in ordinary Portland cement (OPC). However, their effects on the grindability and hydration mechanism have not been fully understood. In this study, the effects of mono-ethylene glycol (MEG) of various concentrations (0, 0.025, and 0.05 %) on OPC grinding characteristics as well as hydration reaction were examined. The use of MEG improved the grinding performance of OPC powder, and this effect became more noticeable with increasing quantities of MEG. Moreover, the addition of MEG substantial influenced the hydration properties of the OPC. Although there was no substantial difference in the reactivity of the aluminate phases, the reactivity of the silicate phases improved at all stages. This effect intensified with increasing concentrations of MEG. Additionally, the amount of calcium carbonate increased with the addition of MEG, indicating that MEG somehow promotes carbonation as well. With all these effects, it was concluded that the MEG proportionally enhanced the mechanical performance.

Effectiveness of a silane coupling agent in a resin luting cement

The objective of this study was to investigate a new silane-containing self-adhesive resin luting cement with both shear bond strength and contact angle studies to determine if silane in a resin cement would chemically bond to a lithium disilicate surface. The silane-containing cement, Panavia SA Cement Universal (Kuraray, Tokyo, Japan) was tested against a control case where a traditional silane treatment was paired with resin-luting cement, Duo-Link Universal (Bisco Inc., Schaumburg, IL, USA) with immediate shear bond strength testing on both polished and etched lithium disilicate, as well as after thermocycling. It was determined that micromechanical retention provided a substantial contribution to bond strength. However, after an aging study with 20,000 thermocycles and then storage for 6 months in 37 °C water, the silane-containing, self-adhesive resin cement significantly decreased in shear bond strength when compared to the control. From contact angle studies, while it was shown that the paste containing the silane did effectively increase hydrophobicity of the treated lithium disilicate surface, it required over 3 h contact time, which was not representative of clinical use.

C–S–H-PCE nanoparticles and anionic surfactants as nucleation agent in cement based materials: Focus on the antagonism

The small solid particles and surfactants inclusion have the potential to furnish abundant nucleation sites, yet the concurrent operation mechanisms in cement remain unclear. Thus, calcium-silicate-hydrate-polycarboxylate ether (C–S–H-PCE) nanoparticles and calcium stearate (CaSt2) all were introduced as composites nucleation agents in this work, and then the properties of fresh cement paste, hydration process and microstructure of hardened pastes were especially investigated. Experimental results demonstrated that C–S–H-PCE and CaSt2 enhanced cement hydration by utilizing their ability to provide nucleation sites, but they were less compatible. Therefore, the combination showed the antagonistic effects: a decrease in fluidity and compressive strength. The decrease in fluidity was mainly attributed to the lowered particle dispersion. The decrease in compressive strength was associated with a lower overall density and increased cumulative porosity of the C–S–H gels. This work establish the theoretical foundation for selecting components of green composite nucleation agents.

Mechanical behaviour of dredging waste in the port of Rio Grande by adding stabilizing agents

ABSTRACT The Port of Rio Grande demands periodic maintenance dredging processes in the access channel of the port complex. These large volumes of dredging waste disposal in the ocean cause environmental and social problems in this region. One possible solution to reduce the impact is onshore disposal, but the sediment has a low support capacity and high compressibility. So, the present paper evaluates the mechanical behavior of dredging waste improved with chemical agents (chemical: pozzolanic Portland cement) and compounds (physical + chemical: fine sand + pozzolanic Portland cement). The results show that the stabilized material reaches compressibility resistance ranging from 400 to 1600 kPa depending on the dosage proposed. A good correlation was observed between the compression resistance results and cement agents’ porosity-volume content. The stabilizing agents using a composite material (sand + Portland cement) achieved better results. The results show that adding stabilizing agents is a satisfactory option to improve the mechanical behavior of dredging waste.

Graphene oxide-encapsulated baghdadite nanocomposite improved physical, mechanical, and biological properties of a vancomycin-loaded PMMA bone cement

Polymethyl methacrylate (PMMA) bone cement is commonly used in orthopedic surgeries to fill the bone defects or fix the prostheses. These cements are usually containing amounts of a nonbioactive radiopacifying agent such as barium sulfate and zirconium dioxide, which does not have a good interface compatibility with PMMA, and the clumps formed from these materials can scratch metal counterfaces. In this work, graphene oxide encapsulated baghdadite (GOBgh) nanoparticles were applied as radiopacifying and bioactive agent in a PMMA bone cement containing 2 wt.% of vancomycin (VAN). The addition of 20 wt.% of GOBgh (GOBgh20) nanoparticles to PMMA powder caused a 33.6% increase in compressive strength and a 70.9% increase in elastic modulus compared to the Simplex® P bone cement, and also enhanced the setting properties, radiopacity, antibacterial activity, and the apatite formation in simulated body fluid. In vitro cell assessments confirmed the increase in adhesion and proliferation of MG-63 cells as well as the osteogenic differentiation of human adipose-derived mesenchymal stem cells on the surface of PMMA-GOBgh20 cement. The chorioallantoic membrane assay revealed the excellent angiogenesis activity of nanocomposite cement samples. In vivo experiments on a rat model also demonstrated the mineralization and bone integration of PMMA-GOBgh20 cement within four weeks. Based on the promising results obtained, PMMA-GOBgh20 bone cement is suggested as an optimal sample for use in orthopedic surgeries.

Immediate and Long-Term Pull-Out Bond Strength of 3D-Printed Provisional Crowns.

Background: Over the past decade, 3D printing technology has revolutionized various fields, including dentistry. Provisional restorations play a crucial role in prosthetic rehabilitation, necessitating the evaluation of their bond strength with different provisional cement agents. Aims: This study is aimed at assessing the immediate and long-term bond strength of 3D-printed dental crowns using three provisional cement agents. Materials and Methods: Provisional crowns (N = 36) were manufactured using 3D modeling software and cemented in dentin analogues (G10 Nema resin). After the crowns' fabrication, they were randomly divided into three groups (n = 12) for cementation with Relyx Temp 3M ESPE, Provicol-VOCO, and Meron-VOCO. Tensile strength tests were conducted using a universal testing machine, with half of the specimens subjected to 2000 thermal cycles before testing. Finite element analysis was employed to assess tensile stress distribution. Results: Statistical analysis (two-way ANOVA and Tukey's test at a 95% confidence level) revealed significant effects of cement type (p = 0.006) and thermal aging (p = 0.001) on bond strength. Glass ionomer cement exhibited the highest immediate resistance, while all types of cement were adversely affected by thermal aging, resulting in decreased bond strength. Conclusion: Thermal aging significantly alters the properties of 3D printing resin and affects the bond strength of provisional cement with 3D-printed crowns. Despite the adverse effects of thermal aging, glass ionomer cement demonstrated the highest immediate resistance. Clinicians should carefully consider these findings when selecting provisional cements for 3D-printed crowns.

Erosion mitigation with biocementation: a review on applications, challenges, & future perspectives

AbstractSoil erosion is a complex natural process that occurs by either individual or combined actions of wind, hydraulic currents, waves, and rain. This study comprehensively reviews biocementation-based soil stabilisation techniques for developing erosion-resilient landforms through an ecologically conscious strategy. The different pathways for biocementation occurring in nature are discussed with a focused view on the microbially induced carbonate precipitation (MICP) technique. MICP relies on biogenic calcium carbonate (CaCO3) precipitation via the urea hydrolysis route to bind the soil grains. The kinetics and factors affecting MICP are succinctly discussed to highlight the practical challenges associated with biocementation. This study emphasises the influence of MICP on erosion resistance (aeolian and hydraulic) and geotechnical properties of soils. The critical assessment of the previous studies revealed that aeolian and hydraulic erosion can be effectively controlled with a small to moderate quantity of biogenic CaCO3 (2% to 10% of soil weight). MICP marginally influences the hydraulic conductivity of soils with a substantial improvement in compressive strength, making it desirous over traditional soil cementation agents for erosion control due to the limited intervention to natural groundwater flow. However, the scientific design and findings of the previous laboratory-scale and pilot-scale research are still inconsistent for standardising biocementation techniques to transition towards upscaling. This study presents critical insights to the researchers of the environmental, geotechnical and geoenvironmental engineering domains to design their upcoming studies to tackle the challenges required for upscaling biocementation technology.

Preparation and application of self-emulsifying curing agent for CO2 high-pressure corrosion-resistant resin cement

In order to solve the problem that oily epoxy resin is not easy to disperse in a cement slurry system and its application is limited due to low stability, a new self-emulsifying curing agent ETB for oilfield cement slurry was prepared by using bisphenol F-type glycidyl ether (BPF), tetraethylenepentamine (TEP) and epoxypropyl trimethyl ammonium chloride (EPTAC) in three steps. The optimized synthesis conditions are n (TEP): n (BPF)= 2.6:1, 65 ℃ addition reaction for 4 h, n (EPTAC): n (TEP)= 1:1, and 75 ℃ for 2 h end-capping reaction. Finally, 20% glacial acetic acid is added for 30 min salt reaction to obtain the self-emulsifying curing agent ETB. The target product was obtained through Fourier transform infrared spectroscopy and nuclear magnetic resonance analysis. The stability shows that BPF resin lotion is uniform and stable compared to other lotions, with an average particle size of 580.9 nm. The application study of ETB emulsified BPF resin lotion shows that when the dosage is 6.0%, the fluidity index n of the resin cement slurry system is 0.887, the consistency coefficient K is 0.178 Pa.sn, the rheological property is good, the high-temperature and high-pressure water loss can be controlled within 50 mL, and the 48 h compressive strength increases by 36.05% compared with the blank cement paste. The high-pressure CO2 corrosion experiment shows that the penetration growth rate of resin cement stone is − 0.168%, which is much lower than the 455.6% of blank cement stone. Before and after corrosion, the compressive strength decline rate of blank cement stone is 25.07%, while the decline rate of resin cement stone is only 2.18%, indicating that resin cement stone has good corrosion resistance. TG-DTG and SEM were used to analyze the corrosion resistance mechanism: the BPF resin lotion was crosslinked and solidified in the cement slurry to form a film, and was tightly filled inside to form a three-dimensional network structure, thus improving the corrosion resistance.

Egyptian volcanic glass powder as a modifier agent for alkali-activated slag cement

Egypt is a rich country with natural volcanic glass, which can be utilized to produce possibility volcanic glass powder (VGP). This VGP can then be employed as a pozzolanic material for the Portland cement (PC) system. In this investigation, for the first time, the possibility to employ Egyptian volcanic glass powder (VGP) as a modifier agent for alkali-activated slag (AAS) cement was studied. The volcanic glass (VG) was delivered from a quarry in the form of lumps pieces. After crushing and powdering, it was blended with slag in proportions of up to 30 wt% of slag (as a partial replacement). The slag free from VGP and those containing VGP were activated by an alkaline activator to produce alkali-activated cement. The effect of various ratios of VGP on flowability, setting time, compressive strength, transport properties, environmental conditions measured by wetting/drying cycles, crystalline phases, hydration products, and microstructures of AAS cement were investigated. The results confirmed that VGP is an amorphous material rich in silica and has a suitable ratio of alumina. The incorporation of 10% VGP was the optimal ratio. Higher ratios of VGP than 10% showed an adverse effect on the AAS cement properties.

Geotechnical studies on cemented and untreated Behshahr loess and Amol clay of Iran

There has been little research into the effects of cement on the geotechnical properties of two types of fine-grained soil with roughly the same grain size. The cement percentages used in this investigation were 0, 4, and 8% by dry weight of soil. Compaction features, consolidation characteristics, unconfined compressive strength (UCS), and Atterberg limits were all determined in the laboratory. Furthermore, scanning electron microscopy (SEM) examinations were used to analyze the microstructures of cemented and untreated loess and clay. Notably, the MDD for loess and clay are 1.72 gr/cm3 and 1.57 gr/cm3 at CC = 0%, respectively, and 1.7 gr/cm3 and 1.55 gr/cm3 at CC = 4%. The OMC for loess and clay are 15% and 22% at CC = 0%, respectively, and 17% and 20% at CC = 4%. At CC = 0%, loess and clay have cohesion values of 25 kPa and 28.7 kPa, respectively, and 190 kPa and 140 kPa at CC = 8%. Internal friction degrees for loess and clay are 24 and 29 degrees at CC = 0%, respectively, and 36 and 34 degrees at CC = 8. The consolidation test findings demonstrated that increasing the cement proportion reduced cemented soils’ compressibility. The Plasticity Index (PI) rose as cement concentration increased. However, significant percentages of cement concentration reduced the plasticity index. Furthermore, adding cement agents resulted in significant improvements in elasticity modulus and UCS for both soils. The SEM results indicated that the cement-treated loess was denser and more homogenous than the cement-treated clay sample. Triaxial tests reveal that cement particles improve cohesiveness and internal friction angle.

Synergistic Effect of Linezolid Incorporated Chitosan Nanoparticles in Restorative Dental Cements – A Promising Dental Formulation.

Chitosan is considered one of the best materials for use as a drug delivery vehicle. Chitosan is incorporated into dental cement to enhance its properties. Previous investigators have found its antibacterial activity near dental restorations, which was insufficient to produce a clinically significant effect. Hence, the incorporation of various antibacterial agents was proposed. Linezolid is one of the oldest drugs in the oxazolidinone antibiotics category, approved by the US FDA in 2000. It is used to treat various antibiotic-resistant bacterial infections. However, there needs to be more literature regarding using linezolid with chitosan. Current research aims to prepare and characterize chitosan nanoparticles with linezolid for use in dental cement. Chitosan nanoparticles were prepared using the ionotropic gelation technique. They were incorporated with Linezolid, and samples were analyzedby FTIR spectroscopy, Particle size analysis, Transmission Electron Microscopy, High-performance liquid chromatography analysis, antibacterial activity, and biocompatibility. Linezolid was successfully incorporated into chitosan. Chitosan's FTIR spectrum reflected the functional groups present in chitosan, and their peaks were superimposed in the presence of linezolid. Both chitosan and chitosan with linezolid had similar particlesizes (142nm). Linezolid was released from chitosan effectively on the 1st and 7th days (19.78 and 144.14μg/ml). The formulation showed antibacterial activity and was not cytotoxic to cells. Thus prepared linezolid incorporated chitosan is a promising material to be used as an antimicrobial agent in dental cement. Its bio-physico-chemical properties are promising for use in dental cement. In the future, these linezolid-loaded chitosan nanoparticles may be added to various restorative materials.

Removal of Impurities from EAFD Ammonium Carbonate Leachate and Upgrading the Purity of Prepared ZnO.

The paper describes cementation as a suitable method applied in the refining of EAFD leachates in order to obtain required purity of ZnO for specific industrial application. For study of cementation conditions, the leachate from alkaline leaching with (NH4)2CO3 was used. The leachates contained a high amount of zinc (8000-12,000 µg/mL) and a low content of impurities such as iron, lead, copper, chromium and manganese in the range of 1-21 µg/mL. Cementation conditions were predicted by thermodynamic study, theoretically confirming the viability of the proposed experiments at the considered pH = 8-9. Cementation experiments were carried out using powdered zinc and aluminium (5 g/L) as cementation agents in the first phase separately. To increase the cementation efficiency, their combination was used (2.5:2.5 g/L or 5:5 g/L) at temperatures of 20, 40, 60 and 80 °C for 30 min. The optimum cementation conditions were established as: Zn:Al = 5:5 g/L, 60 °C. Under the given conditions, 100% of Fe, Cu, Pb and Mn were removed from the leachate. The ZnO with the maximum purity of 96.67% was obtained by crystallization of cemented leachate at 105 °C, followed by calcination at 900 °C for 4 h. ZnO with such a purity is suitable for use in the electrical or rubber industries.

Effect and mechanism of high Li2CO3 concentrations on the early hydration of sulfoaluminate cement-based materials

Lithium carbonate (Li2CO3) is a commonly used early strength agent for sulfoaluminate cement based grouting materials. Low concentrations of Li2CO3 (≤30 μmol Li/g in sulfoaluminate cement) can significantly accelerate the early hydration of sulfoaluminate cement. However, the effect of high Li2CO3 concentrations (>30 μmol Li/g in sulfoaluminate cement) on the early hydration of sulfoaluminate-cement-based materials (SCBMs) is unclear. In this study, the effects of high concentrations of lithium ion (Li+) and carbonate ion (CO32) on the early hydration of SCBMs (C4A3S¯–CaSO4–CaO) with different mineral compositions (systems T1 and T2) were investigated by hydration calorimetry, X-ray diffraction, and ion concentration measurements. The results revealed that both Li+ and CO32− promoted the hydration of C4A3S¯. Li+ and CO32− each reacted with aluminum and calcium in solution, and the formation of ettringite was suppressed when they were present. At low aluminum and high calcium concentrations in solution (system T1), ettringite formation was controlled mainly by the low concentration of aluminum. Less ettringite was generated, and the inhibition of ettringite formation by both Li+ and CO32− was weaker. At high concentrations of both aluminum and calcium in solution (system T2), ettringite formed more rapidly than in system T1, and Li+ and CO32− inhibited its formation to a greater extent. Li2CO3 affected the amount of ettringite by changing aluminum ion and calcium ion in slurry, thus leading to the change of hydration heat release. These new insights into the interaction between Li2CO3 and SCBMs contribute to the theoretical foundation for cement hydration control.

Study of Bonding between Façade Stones and Substrates with and without Anchorage Using Shear-Splitting Test—Case Study: Travertine, Granite, and Marble

This paper presents an investigation into the bond strength of three common façade stones, namely, travertine, granite, and marble, to a concrete substrate using a shear-splitting test. The effects of anchorage, the number of curing days, and the presence of an anti-freezing agent in cement–sand mortar on bond strength were studied. The results show that the number of curing days had a significant impact on the bond strength between the stones and the substrates. The presence of an anti-freezing agent and accelerator increased bonding during the initial days, but this effect gradually decreased. The use of anchorage had a positive effect on the bond strength, particularly with fewer curing days. Granite had the lowest bond strength when no anchorage was used due to its low permeability. Based on the findings, a novel fuzzy logic approach was proposed to predict the bond strength. This study provides valuable insights into improving the bonding of façade stones to substrates and can aid in the safe and efficient use of these materials in construction.

Effect of calcium alumina silicate hydrate nano-seeds on the hydration of low clinker cement

The replacement of cement clinker with supplementary cementitious materials (SCMs) is considered a very effective way of carbon reduction. However, the slow pozzolanic reaction of SCMs weakens the early strength, which hinders its application. In this study, the dedicated nucleating agents for Al-rich SCMs, C-A-S-H nano-seeds, were synthesized by co-precipitation using polycarboxylate superplasticizer (PCE) as dispersant. The performances of four nano-seeds with different Al/Si and their effects on hydration in 50% metakaolin cement (MK50) were investigated in detail. The results showed that C-A-S-H nano-seeds had a greater strengthening effect than C-S-H nano-seeds especially at early ages, and also accelerated setting, with Al/Si = 0.10 being the most significant. The Al/Si = 0.10 nano-seeds advanced the second main exothermic peak by 6.7 h, promoting the production of stratlingite and causing the highest contents of CH and bound water in hydrated samples. It was also demonstrated by 27Al NMR that C-A-S-H nano-seeds enhanced the reaction degree of metakaolin by producing more C-A-S-H than AFt or AFm. The pozzolanic activity was further explored in the reaction between metakaolin and CH. This study aims to develop an efficient strengthening agent (i.e., C-A-S-H nano-seeds) for low clinker cement, and to reveal the mechanistic difference between them and common C-S-H seeds from the perspectives of hydration and pozzolanic reactions, which is of great significance for the carbon emission reduction of cement industries and solid waste utilization.

Industrial Scale Testing and Evaluation of Silver Recovery Process

In this paper an industrial scale testing and evaluation of a silver recovery process for treating silver-containing materials is presented. The process that is based on the thiourea leaching, followed by silver cementation allows for recovery of the majority of silver as a metallic product. The thiourea leaching was developed specifically for the zinc cake residue, produced from the conventional zinc roast-leaching process at the KCM 2000 AD (Bulgaria), which contains up to 200 g/t silver. The material has a complex zinc ferrite dominated mineralogy with minor zinc hydrosulfate, gypsum, anglesite and plumbojarosite. The feed zinc cake residue is washed with water to remove water soluble zinc by pulping it into 25-30% solids slurry. The washing is carried out in 60 minutes and the resulted slurry is sent to the solid/liquid separation section for filtration. The resulted solids are sent to thiourea leaching and the zinc-containing solution is sent for further zinc recovery. The washed (water-soluble zinc free) solids is pulped into 20% solids slurry. Using thiourea as lixiviant, ferric iron as oxidant, sodium metabisulfite as a reductant and sulfuric acid for pH control, the leaching is performed for 35 minutes at 35oC. Within the leaching process the operating conditions are controlled to allow high silver extraction, while reducing the detrimental effects of thiourea degradation. Silver is recovered from the pregnant leach solution by cementation that results in the formation of a high-grade silver cement product. Iron powder is used as a cementation agent to recover over 94% silver at ambient temperature for 90 minutes. Details of the development work and key process steps are described. The operational data and outcomes of the industrial scale testing are presented along with process performance evaluation.

Menthol as a Cementing Agent for Superficial Undisturbed Sands: Applicability and Soil Structure Analysis

Menthol as a Cementing Agent for Superficial Undisturbed Sands: Applicability and Soil Structure Analysis

Evaluating the Effect of Different Stress Path Regimes on Borehole Deformation Using Convergence Measuring Device

A laboratory study was conducted to investigate the borehole deformation of poorly cemented sandstone rocks with Uniaxial Compressive Strength (UCS) less than 10 MPa under different stress path regimes by using a convergence measuring device (CMD). Synthetic thick-walled hollow cylinders (TWHCs) comprised of sand grains, Portland cement and water were prepared for this study. A series of mechanical tests including uniaxial and triaxial compression tests were performed to examine the physical properties of the artificial sandstones. A vertical displacement loading rate of 0.07 mm/min and confining pressure at a rate of 0.2 MPa/min were applied for the experiments. The CMD was deployed inside the TWHC specimen to measure the borehole deformation. Five different stress paths were applied to the specimens to investigate the effect of stress paths, and three different cement agent contents (10%, 12% and 14%) were considered to study the effect of cement content on the borehole failure. The effect of the cement content on the borehole failure was found to be more significant than the effect of change in stress path regimes.

METODE FUZZY UNTUK MENENTUKAN KELAYAKAN AGEN SEMEN (STUDI KASUS CV. GANESHA JAYA MANDIRI)


 Padang Cement is the oldest cement factory Indonesia. n marketing cement to various regions, PT. Semen Padang collaborates a lot with distributors. and it is from this distributor that cement reaches various regions. This study aims to examine the feasibility of agents from distributors to become cement agents. In this study, determining this feasibility is limited by two indicators, namely capital and demand and using the Mamdani method of Fuzzy logic.

Sound absorption characteristics of surface perforated mortar with micro-sized pores

Surface perforated mortar (SPM) is a cement-based acoustic material that can reduce railway noise. SPM has macro-sized holes on its surface, and the geometry of the holes influences the majority of the absorption performance of SPM. A previous study achieved a higher sound absorption performance than that of traditional pervious concrete by attenuating the resonance caused by the holes. Given that most of the acoustic materials are porous, it was hypothesized that micro-sized pores can enhance the sound absorption performance of SPM. Therefore, this paper exploits aluminum powder as a foaming agent for cement and investigates the effect of the micro-sized pores on the sound absorption of SPM. An in-situ sound absorption test results revealed that incorporating micro-sized pores in SPM improves the sound absorption performance by 133%. The frequency range of sound absorption is mainly dependent on the geometry of the macro-sized holes, and the amount of micro-sized holes affects the degree of sound absorption. Based on the experimental studies on the effects of the geometry of the macro-sized holes and the amount of the micro-sized holes, the design guidelines for SPM are proposed.