scholarly journals Study on High Performance Polymer-Modified Cement Grouts

CivilEng ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 134-157 ◽  
Author(s):  
Costas A. Anagnostopoulos ◽  
Melina Dimitriadi
Keyword(s):  
Epoxy Resin ◽  
Construction Projects ◽  
High Performance ◽  
Setting Time ◽  
Rheological Behaviour ◽  
Acrylic Resin ◽  
Cementitious Materials ◽  
Setting Times ◽  
High Performance Polymer ◽  
Cement Grouts

Engineers worldwide use various additives or chemical admixtures, such as polymer latexes, to improve the properties of cementitious materials for many construction projects. In this paper, the influence of acrylic or epoxy resin emulsions, along with a polycarboxylate superplasticiser on some basic properties (rheological behaviour, setting time, bleeding, strength) of thick cement grouts is presented. The experimental approach included the use of different polymer dosages mixed with grouts made of low water to cement ratios. The laboratory tests revealed that the incorporation of acrylic resin in grouts marginally affected the viscosity, whereas a significant increase in viscosity was obtained when an epoxy resin was added. Regardless of the prolonged setting times, both polymers improved the development of early or final strength. An acrylic resin dosage ranging from 0.25% to 0.75% and an epoxy resin dosage from 5% to 7.5% displayed the highest strength values, at all water to cement ratios. Additionally, all the polymer-modified grouts exhibited a higher bleed capacity, a fact that is significantly important where the bleeding of the grouts is crucial.

scholarly journals Experimental Study of Blended Binders with Metakaolin

2021 ◽  
Vol 13 (19) ◽  
pp. 10548
Author(s):  
Christian Cremona ◽  
Stéphanie Vildaer ◽  
Maxim Cadillac
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Autogenous Shrinkage ◽  
Rheological Behaviour ◽  
Mineralogical Composition ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Hardened Concrete ◽  
Flash Calcination ◽  
Creep Measurements

Three metakaolins are evaluated for use as supplementary cementitious materials in cement-based systems. The metakaolins vary in mineralogical composition and in fabrication (traditional and flash calcination), but are quite similar in their surface area (16–19 m2/g), but are quite similar in mineralogical composition. Performance of metakaolin mixtures will be compared to two control mixtures (standard concrete for foundation C40/50 and high performance concrete C60/75). In this study, the properties of fresh concrete and the mechanical and durability properties of hardened concrete will be examined. The rheological behaviour are aimed to determine the effect of metakaolin on mixture workability. Compressive, tensile and flexural strength and elastic modulus will be measured at various concrete ages. The influence of metakaolin on durability is assessed through rapid chloride migration and carbonation measurements. For high performance concrete mixtures, drying and autogenous shrinkage will be monitored and creep measurements are performed and compared.

Studies of the Physical Properties of Cycloaliphatic Epoxy Resin Reacted with Anhydride Curing Agents

2017 ◽  
Vol 737 ◽  
pp. 248-255 ◽  
Author(s):  
Tae Hee Kim ◽  
Dae Yeon Kim ◽  
Choong Sun Lim ◽  
Bong Kuk Seo
Keyword(s):  
Physical Properties ◽  
Reaction Kinetics ◽  
Epoxy Resin ◽  
High Performance ◽  
Industrial Applications ◽  
Scanning Calorimetry ◽  
Low Viscosity ◽  
High Performance Polymer ◽  
Curing Agents ◽  
The Impact

The preparation of high performance epoxy composites for industrial applications has been extensively researched. In this report, we study the change in physical properties and reaction kinetics between epoxy resin and curing agents of similar geometry. For the experiments, celloxide 2021P, an epoxy resin having low viscosity, was blended with three different curing agents: methylhexahydropthalic acid, methyltetrahydropthalic acid, and 5-norbornene-2, 3-dicarboxylic anhydride. The amount of 1, 2-dimethylimidazole catalyst was controlled, and the highest heat flow temperature (Tpeak) was observed at around 145 °C. The impact on reaction kinetics relative to the change in heating rate was studied with differential scanning calorimetry (DSC) for each of the curing agents. The glass transition temperature (Tg) of each composition was measured with a second DSC cycle. The prepared epoxy compositions were thermally cured in a metallic mold to provide pure epoxy resins without fillers. Finally, the flexural strengths of these resins were compared to each other. The authors believe that insights into choosing an appropriate epoxy binder are useful when it comes to the overall preparation of high performance polymer composites.

Effect of Fly Ash and nanoCaCO3 on the Setting Time of Cement Paste

2013 ◽  
Vol 405-408 ◽  
pp. 2885-2888
Author(s):  
Zhi Qin Zhao ◽  
Zhi Ge ◽  
Ren Juan Sun ◽  
Gong Feng Xin ◽  
Da Wei Huang
Keyword(s):  
Experimental Study ◽  
Fly Ash ◽  
Cement Paste ◽  
Setting Time ◽  
Test Group ◽  
Cementitious Materials ◽  
Ash Content ◽  
Setting Times

This paper presents an experimental study to evaluate the effects of fly ash and nanoCaCO3 on setting time of cement paste. The test group included the contents of fly ash was 30%, 40%, 50%, 60% and content of nanoCaCO3 was 2.5%, 5%, 10%, 20%. Results indicate that setting time was increased with the incorporation of fly ash, shortened with the incorporation of nanoCaCO3. The incorporation of 5% nanoCaCO3 by mass of cementitious materials reduced initial and final setting times by 60 and 70 min, respectively. In comparison to the referenced paste with 40% fly ash. The best fly ash content appear to be 40% when nanoCaCO3 was added.

scholarly journals Synergetic–Complementary Use of Industrial Solid Wastes to Prepare High-Performance Rapid Repair Mortar

2021 ◽  
Vol 8 ◽  
Author(s):  
Jingwei Li ◽  
Dong Xu ◽  
Xujiang Wang ◽  
Kun Wang ◽  
Wenlong Wang
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
Setting Time ◽  
Cementitious Materials ◽  
Solid Wastes ◽  
Calcium Sulfoaluminate Cement ◽  
Rapid Repair ◽  
Calcium Sulfoaluminate ◽  
Repair Mortar ◽  
Environmental Friendly

With the vigorous development of infrastructure engineering, there are growing demands for high-performance rapid repair mortar, especially those using environmental-friendly and low-carbon cementitious materials. Hereupon, this work explored an innovative approach for rapid repair mortar preparation using solid waste-based calcium sulfoaluminate cement. The calcium sulfoaluminate cement was first prepared via synergetic–complementary use of industrial solid wastes and then adopted to prepare rapid repair mortar by proportionally mixing with standard sand and four additives (i.e., polycarboxylate superplasticizer, lithium carbonate, boric acid, and latex powder). The mechanistic analysis indicated that the four additives comprehensively optimized the mechanical strengths, fluidity, and setting time of rapid repair mortar by adjusting the hydration process of calcium sulfoaluminate cement. The test results showed that the 2-h compressive and flexural strength, and 1-day bonding strength of the prepared rapid repair mortar were 32.5, 9.2, and 2.01 MPa, respectively, indicating excellent early-age mechanical performance. In addition, the 28-day compressive and flexural strengths of the rapid repair mortar reached 71.8 and 17.7 MPa. Finally, a life cycle assessment and economic analysis indicated that this approach achieved environmental-friendly utilization of industrial solid wastes, and cost-effective and energy-saving natures, which supports current trends towards a circular economy and green sustainable development.

scholarly journals The Effect of the Thermosensitive Biodegradable PLGA–PEG–PLGA Copolymer on the Rheological, Structural and Mechanical Properties of Thixotropic Self-Hardening Tricalcium Phosphate Cement

2019 ◽  
Vol 20 (2) ◽  
pp. 391 ◽  
Author(s):  
Lucy Vojtova ◽  
Lenka Michlovska ◽  
Kristyna Valova ◽  
Marek Zboncak ◽  
Martin Trunec ◽  
...  
Keyword(s):  
Storage Modulus ◽  
Tricalcium Phosphate ◽  
Setting Time ◽  
Human Mesenchymal Stem Cells ◽  
Rheological Behaviour ◽  
Poly Lactic Acid ◽  
Lag Phase ◽  
The Novel ◽  
Setting Times ◽  
Poly Ethylene

The current limitations of calcium phosphate cements (CPCs) used in the field of bone regeneration consist of their brittleness, low injectability, disintegration in body fluids and low biodegradability. Moreover, no method is currently available to measure the setting time of CPCs in correlation with the evolution of the setting reaction. The study proposes that it is possible to improve and tune the properties of CPCs via the addition of a thermosensitive, biodegradable, thixotropic copolymer based on poly(lactic acid), poly(glycolic acid) and poly(ethylene glycol) (PLGA–PEG–PLGA) which undergoes gelation under physiological conditions. The setting times of alpha-tricalcium phosphate (α-TCP) mixed with aqueous solutions of PLGA–PEG–PLGA determined by means of time-sweep curves revealed a lag phase during the dissolution of the α-TCP particles. The magnitude of the storage modulus at lag phase depends on the liquid to powder ratio, the copolymer concentration and temperature. A sharp increase in the storage modulus was observed at the time of the precipitation of calcium deficient hydroxyapatite (CDHA) crystals, representing the loss of paste workability. The PLGA–PEG–PLGA copolymer demonstrates the desired pseudoplastic rheological behaviour with a small decrease in shear stress and the rapid recovery of the viscous state once the shear is removed, thus preventing CPC phase separation and providing good cohesion. Preliminary cytocompatibility tests performed on human mesenchymal stem cells proved the suitability of the novel copolymer/α-TCP for the purposes of mini-invasive surgery.

scholarly journals Intrinsic modification of repair mortars made with EVA and CaO, impacts at the earlier ages

2018 ◽  
Vol 199 ◽  
pp. 07004
Author(s):  
Inès L. Tchetgnia Ngassam ◽  
Wolfram Schmidt ◽  
Hans Beushausen ◽  
Hans-Carsten Kühne
Keyword(s):  
Hydrodynamic Radius ◽  
Pore Solution ◽  
Positive Impact ◽  
Mixing Time ◽  
Setting Time ◽  
Rheological Behaviour ◽  
Ethylene Vinyl Acetate ◽  
Cementitious Materials ◽  
Rheological Parameters ◽  
Repair Mortars

Many studies have been realised on polymer-modified mortars (PMMs). Among the polymers used, ethylene vinyl acetate (EVA) has revealed evident interaction between calcium ions and its acetate groups. Most of the studies have shown a positive impact of EVA on mortar performance, which is enhanced by the combination of the EVA with calcium oxide CaO. However, there is still a lack of understanding of the nature of these interactions and no clear link has been established between these interactions and the properties of the cementitious materials at early ages. This article aims to tackle this topic by focusing on the evolution of EVA particles in a pore solution and the properties of a cement modified with EVA and CaO, especially the rheological behaviour. As results, it is observed that the zeta potential of the pore solution decreases when EVA is added. Furthermore, the hydrodynamic radius of this polymer tends to increase over time in the pore solution. On the other hand, the EVA tends to delay the setting time while the CaO accelerates it. For the rheological state, EVA tends to govern the plastic viscosity of the cement paste while CaO governs the yield stress and these parameters are not affected by the mixing time during the first 100 min. Their combination enhances these rheological parameters.

Comparison of Two Evaluating Methods for Establishing the Marginal Fit on Four Heat - Pressed Resin Inlays

2018 ◽  
Vol 69 (4) ◽  
pp. 890-893
Author(s):  
Sorana Baciu ◽  
Cristian Berece ◽  
Adrian Florea ◽  
Andrada Voina Tonea ◽  
Ondine Lucaciu ◽  
...  
Keyword(s):  
High Performance ◽  
Clinical Results ◽  
Marginal Fit ◽  
High Performance Polymer ◽  
Investigation Methods ◽  
Evaluating Methods

In this study were compared two investigation methods, a bi- and tri-dimensional techniques by examining the marginal fit pressed in (BioHPP) Inlays. The study pruved that the BioHPP is a high performance polymer which provides very good clinical results.

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