Effect Of Cement Type Research Articles

Effect of Cement Type on Compacted Iron Ore Tailings-Binder Response Blends: Comparative Study

Effect of Cement Type on Compacted Iron Ore Tailings-Binder Response Blends: Comparative Study

Effect of cement type on vertical marginal discrepancy and residual excess cement in screwmentable and cementable implant-supported monolithic zirconia crowns.

The purpose of this study was to investigate the vertical marginal discrepancy (VMD) and residual excess cement (REC) of cementable and screwmentable monolithic zirconia crowns cemented with different types of cement. Abutments were attached to 40 implant analogues. Crowns were created using computer-aided design/computer-aided manufacturing technology from monolithic zirconia blocks, either with or without a screw access hole (SAC). Crowns created both ways were split into two groups and cemented with resin and zinc polycarboxylate cement under a 5-kg weight. VMD and REC values were evaluated using an X20 zoom stereomicroscope. Data were analysed using two-way ANOVA and the Bonferroni test. According to the two-way ANOVA results, REC measurements differed significantly in the crown design and cement groups. However, whilst VMD values were significantly different in both crown design groups, there was no significant difference in the cement groups. According to the Bonferroni test results, the highest REC (157.241 ± 44.29µm) and VMD (68.052 ± 16.19µm) values were found in the crowns without SAC and cemented with zinc polycarboxylate. Screwmentable crowns are more effective than cementable crowns in reducing REC and VMD. Whilst polycarboxylate cement reduces VMD in screwmentable crowns, resin cement is more suitable for cementable crowns.

Mineralogical Evolution of High-pH/Low-pH Cement Pastes in Contact with Seawater

In facilities for the geological disposal of radioactive waste in coastal areas, the long-term alteration of cementitious materials in engineered barriers is expected to occur due to the ingress of groundwater derived from seawater. Although the reaction between cement and seawater has been studied, the alteration behavior caused by the reaction between seawater and low-pH cement, which is expected to be used in a disposal facility, has not yet been clarified. In this study, the effects of cement type on cement–seawater interactions were investigated, and the chemical stability and mineral evolution of cement pastes caused by reactions with seawater were determined. The dissolution of cement hydrates occurred upon increased contact with seawater, and the formation of secondary minerals, including carbonate and Mg-containing minerals, was observed. The progress of dissolution depended on the mineral composition of the initially formed cement hydrates, and low-pH cement containing pozzolanic materials showed less resistance to seawater. Differences in pH and Si concentration that are due to the type of cement used had a strong influence on the evolution of minerals (especially Mg-containing minerals), implying that the formed mineral species possibly affect the migration characteristics of radionuclide.

Effect of cement type and water-to-cement (w/c) ratio on characteristics of lightweight mortars produced with pumice: a comparative study on calcium aluminate (rapid hardening) and ordinary Portland cements

Effect of cement type and water-to-cement (w/c) ratio on characteristics of lightweight mortars produced with pumice: a comparative study on calcium aluminate (rapid hardening) and ordinary Portland cements

Effect of cement type, luting protocol, and ceramic abutment material on the shade of cemented titanium-based lithium disilicate crowns and surrounding peri-implant soft tissue: a spectrophotometric analysis.

The objective of the study was to analyze the impact of cement, bonding pretreatment, and ceramic abutment material on the overall color results of CAD-CAM ceramic crowns bonded to titanium-based hybrid abutments. For single implant restoration of a maxillary lateral incisor a total of 51 CAD-CAM-fabricated monolithic lithium disilicate crowns were fabricated and subsequently bonded onto 24 lithium disilicate Ti-base abutments, 24 zirconia Ti-base abutments and 3 resin abutment replicas as a control group. The 48 copings were cemented with three definitive and one provisional cement on both grit-blasted and non-blasted Ti-bases. The color of each restoration and surrounding artificial gingiva was measured spectrophotometrically at predefined measuring points and the CIELAB (ΔEab) color scale values were recorded. The color outcome of ceramic crowns bonded to hybrid abutments and soft tissues was affected differently by cements of different brands. Grit-blasting of Ti-bases prior to cementing CAD-CAM copings affected the color results of all-ceramic crowns. There was a significant difference (P = .038) for the median ΔE value between blasted and non-blasted reconstructions at the cervical aspect of the crown. Full-ceramic crowns on zirconia Ti-base abutments exhibited significantly lower ΔE values below the threshold of visibility (ΔE 1.8). In all subcategories tested, the use of a highly opaque temporary cement demonstrated the lowest median ΔE for both the crown and the artificial gingiva. Various cements, core ceramic materials and airborne particle abrasion prior to bonding can adversely affect the color of Ti-base supported ceramic crowns and peri-implant soft tissue. However, zirconia CAD-CAM copings and an opaque cement can effectively mask this darkening.

A machine learning approach for assessing the compressive strength of cementitious composites reinforced by graphene derivatives

The potential reinforcement effect of graphene derivatives (GDs) on cementitious composites (CCs) has attracted significant attention. Previous studies, however, have produced varied results regarding the impact of GDs on CCs. This can be attributed to differences in the properties of GDs and the fabrication details of CCs reinforced by GDs. Experiments to explore these factors are both time-consuming and cost-ineffective. Additionally, no predictive model currently exists for assessing the influence of GDs on the compressive strength of CCs. In terms of Machine Learning (ML), most existing models focus on continuous parameters, including mixture design properties of CCs and reinforcing filler content, but ignore discontinuous parameters such as dispersion technique of GDs in CCs, curing type, and type of GDs.Compiling a unique dataset, this study tailors ML models to comprehensively explore the effect of GDs inclusion on the compressive strength of CCs, considering continuous and discontinuous parameters, including GD properties, fabrication details, and mixture design properties. The most used dispersion techniques and types of GDs were divided into different categories in this study. Moreover, the dataset included cement strength grade and fineness modules to distinguish between the effect of cement types' variety and GDs. Finally, the backwards elimination technique confirmed the necessity of such a customized dataset for trustworthy predictions.Artificial neural networks (ANN), decision trees, and support vector regressors could successfully investigate the impact of GDs' inclusion on the compressive strength of CCs, with ANN demonstrating superior prediction performance. Among the GDs properties, sensitivity analysis revealed that lateral size had the highest effect. Among the fabrication conditions, the dispersion technique had the greatest effect. Considering all investigated parameters, the water-to-cement ratio was considered the most influential, followed by lateral size and curing time. A low w/c significantly reduces the strength growth rate due to poor dispersion of GDs.

Effect of Cement Type and Water-to-Binder Ratio on k-value of Low-Calcium Fly Ash for Concrete Compressive Strength

Effect of Cement Type and Water-to-Binder Ratio on k-value of Low-Calcium Fly Ash for Concrete Compressive Strength

Effect of Cement Type on Fracture Resistance and Mode of Failure of Monolith vs Bilayered Zirconia Single Crowns.

To compare the fracture resistance and the mode of failure between monolith second-generation zirconia and bilayered first-generation zirconia single crowns cemented by resin cement and glass ionomer cement (GIC). A total of 36 maxillary first premolar crowns (5 mm in length × 4 mm in cervical diameter, with a base of 6 mm) were computer-aided design-computer-aided manufacturing (CAD-CAM) milled. They were divided into the following two groups (n = 18) according to the fabrication techniques: Group M - monolith zirconia crown (1-mm axial thickness and 2-mm occlusal thickness) and group B - bilayer zirconia crown (0.5-mm axial thickness and 1-mm occlusal thickness). Each group was further subdivided into the following two subgroups (n = 9) according to the cement used: Subgroup G - cemented using GIC; subgroup R - cemented using resin cement. All crowns were cemented to their corresponding resin dies and stored in distilled water for 72 hours. Each specimen was mounted to the lower member of the universal testing machine with a load cell of 5 kN and a crosshead speed of 0.5 mm/minute. Failure modes were analyzed for fractured parts using scanning electron microscopy (SEM). Subgroup MR recorded the highest fracture resistance mean value (3616 ± 347.2 N) while the BG subgroup recorded the statistically significant lowest fracture resistance mean value (1728.7 ± 115.3 N). One-way analysis of variance (ANOVA) followed by pairwise Tukey's post hoc tests revealed a statistically significant difference (p = 0.0001) between groups M and B. One-way ANOVA followed by pairwise Tukey's post hoc tests also showed a statistically significant difference (p = 0.0297) between the types of cement used (subgroups G and R). Monolith zirconia crowns had better mean fracture resistance than bilayered zirconia crowns. Resin cement improved the fracture resistance compared to GIC. Monolith zirconia crowns showed bulk fracture while bilayered zirconia crowns showed chipping fracture. Monolith zirconia crowns present a good prosthetic alternative overcoming the veneer chipping drawback of bilayered zirconia crowns. In addition, resin cement could increase the fracture resistance of zirconia crowns.

Effect of Cement Type and Water-to-Cement Ratio on Fresh Properties of Superabsorbent Polymer-Modified Cement Paste

Superabsorbent polymer (SAP) is a material with the ability to absorb liquid and desorb liquid from and to the environment, and it can ensure the internal curing of cementitious composites. Although the fresh state properties of SAP-modified mixtures (SAPCP) are affected and have been investigated nowadays, the rheological properties of SAPCP are still a virgin field and they are worth studying. Hence, the current study was aimed and conducted to observe what occurred if cements with different chemical compositions, various ratios of water/cement (w/c) and SAP were used together. Accordingly, CEM I 42.5R, CEM II/A-LL 42.5R and CEM IV/B (P) 32.5R were selected as binders in the mixtures, and w/c ratios were 0.40 and 0.50 for SAPCPs. In total, 24 mixtures were designed, produced and tested in the laboratory and spreading table tests, Vicate tests, viscosity tests and shear tests were conducted on the fresh state of the mixtures to observe the fresh behavior of SAPCPs. As a result, it was determined that the SAP, cement and w/c combinations considered in the article were effective on SAPCP fresh properties and rheology. However, it was determined that the use of high amounts of SAP in the mixture, high cement fineness and high oxide ratios in the cement (ratios of silicon dioxide/calcium oxide and aluminum oxide/calcium oxide) negatively affected not only the fresh state properties, but also the rheology. Moreover, the coexistence of the aforementioned negative conditions was the most unfavorable situation: high SAP ratio + high cement fineness + high oxide ratio in SAPCP. For these reasons, it was concluded that cement fineness and chemical composition should be taken into account in the rheology/workability-based design of SAPCPs. Then, the SAP content can be regulated for design purposes.

ASR performance of concrete at external alkali supply – effects of aggregate mixtures and blended cement

ABSTRACT The long-term durability of concrete pavements in wet-freeze climate is influenced by deicing salts used for winter maintenance of roads. Alkaline deicers could also be an external source of alkalis, therefore, their role in respect to the development of deleterious alkali-silica reaction (ASR) should be considered. The performance of mineral aggregate mixtures in concrete was studied using RILEM test procedure ‘60°C concrete test with external alkali supply’. Air-entrained concrete specimens were exposed to cyclic temperature changes, wetting-drying and NaCl solution immersion. Tests revealed the development of concrete expansion in time and associated changes of its elastic modulus for 31 mixtures of fine and coarse aggregate and Portland and fly ash or slag blended cements. The expansive behaviour of air-entrained concrete was strongly influenced by the presence of micro- and cryptocrystalline silica in aggregates. A replacement of nonreactive limestone sand by moderately reactive quartz sand resulted in a substantial enhancement of concrete expansion by a factor of three. The observed reduction of elastic modulus was correlated with more abundant presence of alkali-silica reaction products in concrete. Effects of cement type (CEM I, CEM II/A-V, CEM II/B-S) on the ASR performance of concrete with crushed coarse aggregate and quartz sand are discussed.

The Effect of Cement Type and Granulometry on the Injectability of Suspension Grouts for Soil Improvement – A Mini Review

The safe construction and operation of many engineering projects often requires the improvement of the properties and mechanical behavior of the soil formations occurring in their area. Impregnation injections are one of the oldest methods of improving soil formations and present a wide range of applications. The injectability and penetrability of cement-based slurries are significantly affected by factors such as cement granulometry, water-to-cement ratio, grain size and degree of sand compaction, type and dosage of slurry admixtures, mixing process and the impregnation pressure. The object of this paper is to investigate the effect of cement suspensions type and granulometry on the injectability and penetrability within soil formations.

Effects of Cement Type, Water-Cement Ratio, Specimen Size, and Curing Time on Concrete Electrical Resistivity

Effects of Cement Type, Water-Cement Ratio, Specimen Size, and Curing Time on Concrete Electrical Resistivity

The Influence of Cement Type on the Properties of Plastering Mortars Modified with Cellulose Ether Admixture.

In this article, the effect of cement type on selected properties of plastering mortars containing a cellulose ether admixture was studied. In the research, commercial CEM I Portland cement, CEM II and CEM III, differing in the type and amount of mineral additives, and cement class, were used as binders. Tests of consistency, bulk density, water retention value (WRV), mechanical properties and calorimetric tests were performed. It was proved that the type of cement had no effect on water retention, which is regulated by the cellulose ether. All mortars modified with the admixture were characterized by WRV of about 99%. High water retention is closely related to the action of the cellulose ether admixture. As a result of the research, the possibility of using cement with additives as components of plasters was confirmed. However, attention should be paid to the consistency, mechanical properties of the tested mortars and changes in the pastes during the hydration process. Different effects of additives resulted from increasing or decreasing the consistency of mortars; the flow was in the range from 155 mm to 169 mm. Considering the compressive strength, all plasters can be classified as category III or IV, because the mortars attained the strength required by the standard, of at least 3.5 MPa. The processes of hydration of pastes were carried out with different intensity. In conclusion, the obtained results indicate the possibility of using CEM II and CEM III cements to produce plastering mortars, without changing the effect of water retention.

Vital pulp therapy following pulpotomy in immature first permanent molars with deep caries using novel fast-setting calcium silicate cement: A retrospective clinical study

ObjectivesTo compare the success rate of vital pulp therapy following complete pulpotomy in immature first permanent molars, during caries treatment, using novel fast-setting calcium silicate cement (Novel CSC) versus MTA. MethodsSix- to eight- years old children, who received pulpotomy of first immature permanent molar using one layer novel CSC (Protooth) or two layers slow-setting MTA (MTA Angelus) covered with glass ionomer were recalled for radiographic and clinical evaluation after two years. The effects of cement type, age, gender, jaw, anesthesia type, and restoration type were assessed on the clinical success of pulpotomy and continued root formation (apexogenesis) as the treatment outcome. ResultsOut of 366 included teeth in the study, 316 teeth were available for statistical analysis. The mean observation time was 28.2 ± 2.7 months. Novel CSC showed significantly higher clinical success rate (93.1%) compared to MTA (84.5%). Restored teeth with stainless steel crowns after pulpotomy and treatments performed under general anesthesia had a statistically significant effect on treatment outcome in contrast to age, gender, and jaw type. ConclusionThe observations of this retrospective study suggested that the success rate of vital pulp therapy following complete pulpotomy using one layer fast-setting novel CSC was significantly higher than slow-setting MTA covered with glass ionomer. Treatment under general anesthesia and restoration using stainless steel crowns influenced the treatment outcome. Clinical significanceNovel fast-setting calcium silicate cement is a promising new biomaterial for vital pulp therapy in immature permanent molars that allows complete root formation overtime with apexogenesis. Clinicians must also be aware of the importance of immediate definitive restoration and proper sealing and isolation in vital pulp therapy.

The effects of cement type and expanded vermiculite powder on the thermo- mechanical characteristics and durability of lightweight mortars at high temperature and RSM modelling

The results of the impact of cement type and expanded vermiculite powder (EVP) on the thermal, mechanical characteristics and durability of lightweight mortars at high temperature and RSM modelling are presented in the paper. The lightweight mortars were fabricated by replacing fine aggregate with EVP in certain proportions. In the production of the mixtures, two different cement types namely, Portland cement (PC) and calcium aluminate cement (CAC) were used as binders and fine aggregates were replaced with EVP at the rates of 0%, 15%, 30% and 45%. The microstructure, thermal, mechanical properties and durability of PC and CAC mortars produced in this way were determined after standard curing for 28 days at temperatures ranging from 20 °C to 900 °C. Mechanical performance of mortar mixtures was evaluated based on compressive, flexural strength and ultrasonic pulse velocity (UPV). The durability of the specimens was also determined using porosity, water absorption and dry unit weight. Thermal conductivity and Scanning electron microscope (SEM) observations of 28-day mortar specimens were also evaluated. The response surface methodology (RSM) was adopted to develop the relation between parameters and response for thermal conductivity. The test results reported that lightweight refractory and insulating mortar can be manufactured by combined use of CAC and EVP when considered strength and durability and thermal performance after high-temperature exposure. Test results also pointed out that the combined use of CAC and EVP gained significant high-temperature resistance performance in terms of compressive strength as compared to PC blended mortar specimens.

Effects of cement types and addition of quartz and limestone on the normal and carbonation curing of cement paste

Belite-rich cement (BRC) and carbonation curing are vital in the cement and construction industries for reducing carbon emissions and achieving carbon neutrality. In this study, the effects of quartz, limestone, and the type of cement (BRC and ordinary Portland cement) on the carbonation curing and normal curing of cement paste were systematically studied. The water/binder ratio was 0.5, and the replacement ratio of quartz/limestone was 20%. The experimental results showed that adding 20% quartz/limestone to BRC effectively accelerated the carbonation curing process, and the acceleration effect of quartz was more obvious than that of limestone. The compressive strength of the samples with 20% quartz and limestone added to BRC was 72 MPa and 69 MPa, respectively, after 28 days of carbonation curing. These are respectively 1.7 times and 1.6 times higher than the compressive strength of the samples under normal curing. The late-age strength mainly depended on the amount of cement and marginally depended on the addition of quartz/limestone. Quartz improved carbonation efficiency by increasing the porosity of the cement paste and providing nucleation sites for the silica gel formed during carbonation. Moreover, CH, ettringite, monocarboaluminate, and hemicarboaluminate were fully carbonated, and large amounts of alite and belite were carbonated during carbonation curing. The electrical resistivity after 28 days of carbonation curing was 38–72 times higher than its electrical resistivity after 28 days of normal curing. After carbonation curing, the quartz-blended BRC had a high resistivity of 1562 kΩ·cm. Thus, quartz is an effective supplementary material for the carbonation curing of concrete. Moreover, the combination of quartz and BRC has a greater impact on carbonation curing than the combination of limestone and BRC.

Influence of the Type of Cement on the Action of the Admixture Containing Aluminum Powder.

The study of the effect of cement type on the action of an admixture increasing the volume of concrete (containing aluminum powder), used in amounts of 0.5–1.5% of cement mass, was presented. The tests were carried out on cement mortars with Portland (CEM I) and ground granulated blast-furnace slag cement (CEM III). The following tests were carried out for the tested mortars: the air content in fresh mortars, compressive strength, flexural strength, increase in mortar volume, bulk density, pore structure evaluation (by the computer image analysis method) and changes in the concentration of OH− ions during the hydration of used cements. Differences in the action of the tested admixture depending on the cement used were found. To induce the expansion of CEM III mortars, a smaller amount of admixture is required than in the case of CEM I cement. Using the admixture in amounts above 1% of the cement mass causes cracks of mortars with CEM III cement due to slow hydrogen evolution, which occurs after mortar plasticity is lost. The use of an aluminum-containing admixture reduces the strength properties of the cement mortars, the effect being stronger in the case of CEM III cement. The influence of the sample molding time on the admixture action was also found.

Effect of Cement Types and Superabsorbent Polymers on the Properties of Sustainable Ultra-High-Performance Paste.

This study focuses on the effects of superabsorbent polymers (SAP) and belite-rich Portland cement (BPC) on the compressive strength, autogenous shrinkage (AS), and micro- and macroscopic performance of sustainable, ultra-high-performance paste (SUHPP). Several experimental studies were conducted, including compressive strength, AS, isothermal calorimetry, X-ray diffraction (XRD), thermogravimetric analysis (TGA), attenuated total reflectance (ATR)–Fourier-transform infrared spectroscopy (FTIR), ultra-sonic pulse velocity (UPV), and electrical resistivity. The following conclusions can be made based on the experimental results: (1) a small amount of SAP has a strength promotion effect during the first 3 days, while BPC can significantly improve the strength over the following 28 days. (2) SAP slows down the internal relative humidity reduction and effectively reduces the development of AS. BPC specimens show a lower AS than other specimens. The AS shows a linear relationship with the internal relative humidity. (3) Specimens with SAP possess higher cumulative hydration heat than control specimens. The slow hydration rate in the BPC effectively reduces the exothermic heat. (4) With the increase in SAP, the calcium hydroxide (CH) and combined water content increases, and SAP thus improves the effect on cement hydration. The contents of CH and combined water in BPC specimens are lower than those in the ordinary Portland cement (OPC) specimen. (5) All samples display rapid hydration of the cement in the first 3 days, with a high rate of UPV development. Strength is an exponential function of UPVs. (6) The electrical resistivity is reduced due to the increase in porosity caused by the release of water from SAP. From 3 to 28 days, BPC specimens show a greater increment in electrical resistivity than other specimens.

Experimental Investigations on Effect of Compaction, Curing, Water to Cement Ratio, Cement Type and Temperature Variation on the Rebound Hardness of Concrete

It is a known fact that the concrete strength is not only affected by the ingredients present in it, but also by the other factors like types of cement used, compaction deficiency, curing condition, elevated temperature, and different w/c ratios. The influence on the rebound hammer has been illustrated in this paper concerning the hardness of the concrete specimens. The effect of cement types, compacting deficiency, w/c ratio, curing condition, and elevated temperature on concrete compressive strength and rebound hardness has been considered for the analysis. From an experimental study, it is found that the reduction of the compressive strength of concrete is between 6 to 41 percent due to insufficient compaction alone when tested using a destructive method. However, the rebound hammer results revealed that there is no reduction in the rebound index. The rebound hardness test cannot predict the compressive strength due to inadequate curing. It is also reported that the rebound index is significantly reduced, with the destructive strength of the concrete specimens. The study revealed that in the case of M30 and M40 grades of concrete, the percentage reduction of the average rebound index is almost higher in all the cases than the average compressive strength at a temperature ranging from 200°C to 800°C. The strength (rebound hardness) measured is either under or overestimated if no attention has been given to different influencing factors. Thus, a reliable and accurate evaluation of strength cannot be guarantee.

Effect of cement types on carbonation depth of concrete

Reinforced concrete as a building material is the most used in most civil engineering structures. This one is exposed to several attacks (physical, chemical and mechanical). Among these attacks, we can cite the phenomenon of carbonation, which leads to corrosion of the reinforcements and consequently reduces the service life of reinforced concrete structures. In addition, this phenomenon generates additional repair costs, which can sometimes exceed the initial cost of the building. Furthermore, it depends on the type and class of cement, two main classes of cement are used for the formulation of concrete in Algeria, ordinary Portland cements and cements with additions.
 This paper enters in the option of sustainable development, in order to study the behavior of these two types of cements against accelerated carbonation.
 For this purpose, two concrete compositions (based on ordinary Portland cements and cements with additions) were formulated, from these two formulations, samples were made in order to subject them to accelerated carbonation in a chamber rich in CO2 according to the recommendations of the AFPC-AFREM.
 The results obtained clearly show that concretes based on ordinary Portland cements (OPC) are less sensitive to the phenomenon of carbonation compared to concretes based on blended cements.