Heat Release during 3d-Printable Materials Setting and Hardening

2021 ◽  
Vol 1043 ◽  
pp. 37-42
Author(s):  
Galina Slavcheva ◽  
Ekaterina Britvina ◽  
Maria Shvedova
Keyword(s):  
Experimental Data ◽  
Compressive Strength ◽  
Heat Release ◽  
Heat Generation ◽  
Setting Time ◽  
High Strength ◽  
Highly Active ◽  
Control Setting ◽  
Open Time ◽  
Viscosity Modifiers

The paper presents the experimental data on the cement effect typeon the effects of heat generation during the 3D-printable cement materials’setting and hardening. Materials made on the basis of cements CEMI 42.5 RandCEMI 52.5 R, differing in phase contentC3Ain combination with viscosity modifiers of various compositions,have been studied. To control setting kinetics, a penetrometer test was used, hardening kinetics was evaluated by testing the samples for compressive strength after 1, 3, 7, 14, 28 days of hardening. It was found that the useof CEMI 52.5 Rhigh in compositionC3Acauses a significant heating of the mixture already after its setting, which is not observed when using ordinary CEMI 42.5R. The combination of a highly active aluminosilicate modifier with high-strength cement causes a technologically unacceptable reduction in the setting time and open time of mixtures.

Effect of Anhydrite on the Early Hydration Performance of Rapid Setting and Hardening Belite Sulfoaluminate Cement

2017 ◽  
Vol 898 ◽  
pp. 1990-1995 ◽  
Author(s):  
Ming Zhang Lan ◽  
Bin Feng Xiang ◽  
Jian Feng Wang ◽  
Xu Dong Zhao ◽  
Xiao Ying Wang
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
High Strength ◽  
Cement Clinker ◽  
Hydration Kinetics ◽  
Early Hydration ◽  
Free Lime ◽  
Calcium Sulfoaluminate ◽  
Setting Times ◽  
Rapid Setting

In order to investigate the early hydration behavior of rapid setting and hardening belite sulfoaluminate cements, the methods of X-ray Diffraction, Scanning Electron Microscope, Compressive Strength test and Setting Times test were used to identify and quantify the hydration kinetics and microstructure of this new-found cements in China. The results showed that the main mineral compositions of high belite sulfoaluminate cement clinker included calcium sulfoaluminate (4CaO·3Al2O3·CaSO4), belite (2CaO·SiO2), ferrite phase, free gypsum and free lime. It was found that not only the setting time and compressive strength but also the composition of hydration products were influenced by anhydrite to some extent. Meanwhile, a mass of AFt and AFm generated along with the hydration process at different ages, overlapped, crossed and penetrated through calcium silicate hydrate gel and aluminum oxide to form a relatively dense structure which could contribute to the high strength of cement.

scholarly journals Experimental Drillable Magnesium Phosphate Cement Is a Promising Alternative to Conventional Bone Cements

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1925
Author(s):  
Philipp Heilig ◽  
Phoebe Sandner ◽  
Martin Cornelius Jordan ◽  
Rafael Gregor Jakubietz ◽  
Rainer Heribert Meffert ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Phytic Acid ◽  
Mechanical Performance ◽  
Setting Time ◽  
High Strength ◽  
Magnesium Phosphate ◽  
Bone Cements ◽  
Promising Alternative ◽  
Phytic Acid Content ◽  
With Screws

Clinically used mineral bone cements lack high strength values, absorbability and drillability. Therefore, magnesium phosphate cements have recently received increasing attention as they unify a high mechanical performance with presumed degradation in vivo. To obtain a drillable cement formulation, farringtonite (Mg3(PO4)2) and magnesium oxide (MgO) were modified with the setting retardant phytic acid (C6H18O24P6). In a pre-testing series, 13 different compositions of magnesium phosphate cements were analyzed concentrating on the clinical demands for application. Of these 13 composites, two cement formulations with different phytic acid content (22.5 wt% and 25 wt%) were identified to meet clinical demands. Both formulations were evaluated in terms of setting time, injectability, compressive strength, screw pullout tests and biomechanical tests in a clinically relevant fracture model. The cements were used as bone filler of a metaphyseal bone defect alone, and in combination with screws drilled through the cement. Both formulations achieved a setting time of 5 min 30 s and an injectability of 100%. Compressive strength was shown to be ~12–13 MPa and the overall displacement of the reduced fracture was <2 mm with and without screws. Maximum load until reduced fracture failure was ~2600 N for the cements only and ~3800 N for the combination with screws. Two new compositions of magnesium phosphate cements revealed high strength in clinically relevant biomechanical test set-ups and add clinically desired characteristics to its strength such as injectability and drillability.

scholarly journals Strength and Microstructural Investigation of Quaternary Blended High-Strength Concrete

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Ayele Bereda ◽  
Belachew Asteray
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
High Strength Concrete ◽  
Setting Time ◽  
Ceramic Powder ◽  
High Strength ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Microstructural Investigation ◽  
Strength Concrete

This research focuses on studying the effect of different supplementary cementitious materials (SCMs) such as waste ceramic powder (WCP), lime powder (LP), and ground granulated blast furnace slag (GGBS) in combination on strength characteristics and microstructure of quaternary blended high-strength concrete. To achieve the aims of the study, necessary physical and chemical composition tests were done for the raw materials. Then, mixes were designed into control mix with 100% Ordinary Portland Cement (OPC) and experimental mixes containing 30%, 40%, 50%, and 60% of GGBS, WCP, and LP in combination. Tests were conducted during casting and at curing ages of 7 and 28 days. Accordingly, the control mix which is concrete grade 50 (C-50) as per American Concrete Institute (ACI) mix design is used as a reference for comparison of test results with those specimens produced by partial replacement of SCMs. The characterizations of high-strength concrete are done using consistency, setting time, workability, compressive strength, flexural strength, and morphological tests. The optimum percentage replacement is 50% OPC replacement by 30% GGBS + 10% WCP + 10% LP. Based on the experimental investigations, the workability increases as the replacement level of SCMs increases from 30% to 60% by weight. Compressive strength and flexural strength results increase up to 11.41% and 20% when the percentage replacement increases from 30% to 50% of SCMs replacement at 28 days of curing time, respectively. There are also improvement in the microstructure and significant cost saving due to replacing OPC partially with SCMs with proportions mentioned above. Therefore, the practice of utilizing increased percentage of SCMs in quaternary blend in concrete can be beneficial for the construction industry and sustainability without compromising the quality of the concrete product.

scholarly journals A Preliminary Characterisation of Innovative Semi-Flexible Composite Pavement Comprising Geopolymer Grout and Reclaimed Asphalt Planings

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3644 ◽  
Author(s):  
An Thao Huynh ◽  
Bryan Magee ◽  
David Woodward
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
High Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Base Layer ◽  
Reclaimed Asphalt ◽  
Improved Performance ◽  
Environmental Savings

This article considers semi-flexible composite (SFC) pavement materials made with reclaimed asphalt planings (RAP) and geopolymer cement-based grouts. Geopolymer grouts were developed and used to fill the internal void structure of coarse RAP skeletons with varying levels of porosity. The geopolymer grouts were formulated at ambient temperature using industrial by-products to offer economic and environmental savings relative to conventional Portland cement-based grouting systems. They were characterised on flowability, setting time, and compressive strength. The effect of grout and RAP on SFC material performance was evaluated using permeable porosity, compressive strength, and ultrasonic pulse velocity. SFC performance was significantly influenced by both grout type and RAP content. Improved performance was associated with mixtures of high-flowability/high-strength grout and low RAP content. A practical limitation was identified for combination of grout with low-flowability/fast-setting time and well-compacted RAP skeletons. Solids content exceeding 49% by volume was not feasible, owing to inadequate grout penetration. A suite of SFC materials was produced offering performance levels for a range of practical pavement applications. Preliminary relationships enabling prediction of SFC elastic modulus based on strength and/or ultrasonic pulse velocity test data are given. A pavement design is given using SFC as a sub-base layer for an industrial hardstanding.

Preparation of Calcined Phosphogypsum-Based High-Strength Supersulphated Cement

2012 ◽  
Vol 188 ◽  
pp. 199-204 ◽  
Author(s):  
Yu Xin Gao ◽  
Bao Ying Yu ◽  
Fen Lian Xu ◽  
Xi Hua Lin ◽  
Shi Hai Yang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Electron Microscope ◽  
Chemical Composition ◽  
Setting Time ◽  
High Strength ◽  
Strengthening Mechanism ◽  
Composition Analyzer ◽  
Scanning Electron ◽  
Curing Age

Based on mechanical properties, the influences of the clinker dosage(C1, C2, C3), calcination temperature(M1, M2, M3) of phosphogypsum(PG) and specific surface area(S1, S2, S3, S4) on the mechanical properties of supersulphated cement(SSC) were systematically studied; Then SSC with different kinds of PG were chose to research water requirement of normal consistency, setting time and soundness; Strengthening mechanism on SSC were further investigated and analyzed with scanning electron microscope(SEM) and chemical composition analyzer at last. Results showed SSC with conditions of C2, T3 and S3 has 36.4, 56.5 and 72.6MPa standard mortar compressive strength at 7d, 28d and 56d curing age. Calcined Phosphogypsum(CPG)-based high strength SSC is successfully developed.

The Modulus of Elasticity of High-Strength Concrete

2011 ◽  
Vol 261-263 ◽  
pp. 233-237 ◽  
Author(s):  
Zhao Hui Lu ◽  
Zhi Wu Yu ◽  
Yan Gang Zhao
Keyword(s):  
Experimental Data ◽  
Compressive Strength ◽  
Empirical Model ◽  
Modulus Of Elasticity ◽  
High Strength Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Plain Concrete ◽  
Strength Concrete ◽  
Wide Range

The paper discusses the modulus of elasticity of plain concrete for a wide range of compressive strength. A large volume of selected experimental data has been collected from existing literature and then analyzed. Particular emphasis has been given to studying the effects of concrete compressive strength and the type of coarse aggregate on the modulus of elasticity of plain concrete. The adequacy and applicability of the existing models for predicting the modulus of elasticity of high-strength concrete has been critically examined, and a new empirical model is proposed to cover concrete strength up to 125 MPa. The new empirical model seems to perform much better when applied to the published experimental data on normal weight concrete over a wide strength range.

scholarly journals A Novel Solution for Severe Loss Prevention While Drilling Deep Wells

2020 ◽  
Vol 12 (4) ◽  
pp. 1339
Author(s):  
Salaheldin Elkatatny ◽  
Hany Gamal ◽  
Abdulmalek Ahmed ◽  
Pranjal Sarmah ◽  
Shiv Sangaru ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
High Strength ◽  
Drilling Fluids ◽  
Well Bore ◽  
Cement Slurry ◽  
Lost Circulation ◽  
Acid Solubility ◽  
Study Laboratory ◽  
Thief Zone

The loss of circulation is a big problem in drilling operations. This problem is costly, time-consuming and may lead to a well control situation. Much research has investigated the effectiveness of using different chemicals as lost circulation material (LCM) to stop mud and cement slurry losses. However, there remain many limitations for using such LCM types, especially when it comes to field applications. This paper presents a new high strength lost circulation material (HSLCM) that could effectively be used for managing severe lost circulation cases. The HSLCM could easily be pumped into the thief zone where it forms a gel that solidifies after a setting time to provide sealing between the wellbore and the thief zone. With this technique, the material stops the circulation losses, and hence enhances the well bore stability by reducing the well bore stresses. The HSLCM has a high compressive strength and it has a high acid solubility of around 96%. Because the HSLCM has high tolerance towards contamination, it can be utilized with water-based mud or invert emulsion-drilling fluids, hence providing a wide window of applications with the drilling fluids. In this study, laboratory experiments were conducted to evaluate the rheology, thickening time, compressive strength, and acid solubility of the HSLCM. The results showed good performance for the HSLCM as LCM. In addition, a case field study is presented which shows a successful field treatment for severe losses.

Strain of High-Strength Concrete at Peak Compressive Strength

2012 ◽  
Vol 446-449 ◽  
pp. 161-165 ◽  
Author(s):  
Zhao Hui Lu ◽  
Yan Gang Zhao ◽  
Zhi Wu Yu
Keyword(s):  
Experimental Data ◽  
Compressive Strength ◽  
Empirical Model ◽  
High Strength Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Normal Weight ◽  
Strength Concrete ◽  
Normal Weight Concrete ◽  
Wide Range

The paper discusses the strain of high-strength concrete (HSC) at peak compressive strength for a wide range of compressive strength. A large volume of selected experimental data has been collected from existing literature and then analyzed. Particular emphasis has been given to studying the effects of concrete compressive strength and the types of coarse aggregate on the strain of HSC at peak compressive strength. The adequacy and applicability of the existing models for predicting the strain of HSC at peak compressive strength has been critically examined, and a new empirical model is proposed to cover concrete strength up to 125 MPa. The new empirical model seems to perform much better when applied to the published experimental data on normal weight concrete over a wide strength range.

scholarly journals Effect of the Sodium Silicate Modulus and Slag Content on Fresh and Hardened Properties of Alkali-Activated Fly Ash/Slag

Minerals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 15 ◽  
Author(s):  
Xiaowei Ouyang ◽  
Yuwei Ma ◽  
Ziyang Liu ◽  
Jianjun Liang ◽  
Guang Ye
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Pore Structure ◽  
Heat Release ◽  
Setting Time ◽  
Heat Evolution ◽  
Reaction Products ◽  
Hardened Properties ◽  
Alkali Activated ◽  
Slag Content

This paper presents the results of an experimental study performed to investigate the effect of activator modulus (SiO2/Na2O) and slag addition on the fresh and hardened properties of alkali-activated fly ash/slag (AAFS) pastes. Four activator moduli (SiO2/Na2O), i.e., 0.0, 1.0, 1.5, and 2.0, and five slag-to-binder ratios, i.e., 0, 0.3, 0.5, 0.7, 1.0, were used to prepare AAFS mixtures. The setting time, flowability, heat evolution, compressive strength, microstructure, and reaction products of AAFS pastes were studied. The results showed that the activator modulus and slag content had a combined effect on the setting behavior and workability of AAFS mixtures. Both the activator modulus and slag content affected the types of reaction products formed in AAFS. The coexistence of N–A–S–H gel and C–A–S–H gel was identified in AAFS activated with high pH but low SiO2 content (low modulus). C–A–S–H gel had a higher space-filling ability than N–A–S–H gel. Thus, AAFS with higher slag content had a finer pore structure and higher heat release (degree of reaction), corresponding to a higher compressive strength. The dissolution of slag was more pronounced when NaOH (modulus of 0.0) was applied as the activator. The use of Na2SiO3 as activator significantly refined the pores in AAFS by incorporating soluble Si in the activator, while further increasing the modulus from 1.5 to 2.0 prohibited the reaction process of AAFS, resulting in a lower heat release, coarser pore structure, and reduced compressive strength. Therefore, in view of the strength and microstructure, the optimum modulus is 1.5.

Effect of Polyacrylic Acid on Retarding Action and Property of Gypsum Plasters

2014 ◽  
Vol 638-640 ◽  
pp. 1526-1530
Author(s):  
Jia Yu Zhan ◽  
Wan Min Li ◽  
Ning Luo ◽  
Jun Gu
Keyword(s):  
Mechanical Property ◽  
Compressive Strength ◽  
Heat Release ◽  
Acid Concentration ◽  
Polyacrylic Acid ◽  
Setting Time ◽  
Hydration Heat ◽  
Carboxylic Group ◽  
Mass Ratio

Polyacrylic acid was synthesized and used as a retarder additive to prolong the setting time of gypsum plasters. The gypsum paste with the polyacrylic acid at the concentration of 0, 0.1%, 0.2%, 0.3%, 0.4% and 0.5% was studied. The water/gypsum mass ratio was 0.56. The influence of polyacrylic acid concentration on the initial and finial setting time, hydration temperature, morphology of hardened gypsum and mechanical property were extensively investigated. The results show that polyacrylic acid is favorable to increase the setting time which was associated with the reaction of carboxylic group and calcium from the hemihydrate dissolution. The morphology of hardened gysum varied when polyacrylic acid is used. The increase concentration of polyacrylic acid results in a decrease in hydration heat release, flexural and compressive strength.

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