The rheological properties of fresh plaster mortars, with varied contents of porous fillers and polymer admixtures, have been studied. The quantities of fine limestone and expanded perlite, and dosages of methyl hydroxy ethyl cellulose and ethylene vinyl acetate were varied in the experiment. Effective viscosity (at a shear rate from 0.045 to 5.705 s−1) and the thixotropy of the mixes were determined with rotational viscometer for 18 compositions (according to the design of the experiment). Each of the 18 viscosity curves were described with the Ostwald–de-Waele equation. The Experimental–Statistical models describing the dependencies of the parameters of the rheological model and of mix thixotropy on the composition factors were built on the obtained data. ES-models have allowed the individual and synergetic effects of mix components on the rheological characteristics to be evaluated. The expanded perlite powder can increase the viscosity by two times, probably due to its pozzolanic effect increasing the content of the CSH phase during cement hydration. The thixotropy can be increased by the quantity of limestone. The computational experiments with ES-models have made it possible for the information set, without a noticeable interrelation between rheological characteristics, to be stratified into subsets, in which such interrelations differ significantly.
This paper investigates the effect of polymer modifiers (re-dispersible powder, multifunctional additives, methylhydroxyethylcellulose) on the rheological behavior of emulsions, saturated of calcium hydrosilicates to simulate a hydrating cement structure. The subjects of the study were modified emulsions which had varied concentrations of each additive and they were examined comparatively to a base emulsion. Tests were performed with a CR-rheometer (“Himpribor-1”, Tula, Russia) applying the Searle measuring principle at various shear rates to characterize viscosity properties. The performance of modified mixtures within the operating period was analyzed by using two parameters—effective viscosity (η) and the proportion of structural failure (|m|). The test results showed that the most important factor influencing rheological characteristics is the addition of methylhydroxyethylcellulose additive—the higher additive amount in the emulsion, the higher the viscosity. Furthermore it was noted in the work that adding olefin sulfonate sodium salt causes reduced viscosities as well as lower shear moduli. If ethylhydroxyethylcellulose and ethylene vinyl acetate additives are used in the same mixture together, the rate of structural failure |m| can be relatively similar and low regardless of whether the mixture has large or small viscosity values.
Experience of using the Monte-Carlo method in determining optimal plaster compositions with improved strength properties Moskalova K., Aniskin A.https://doi.org/10.13167/2017.14.4 31 Abstract: Considering that modern building materials impose increasing performance requirements, it is necessary to expand the range of building materials and improve their multicomponent composition. The effects of polymer and porous components (expanded perlite sand and carbonate filler -limestone-shell rock) in cement-lime light plaster on the physico-mechanical properties of the mixtures under equal workability conditions of mixtures are analyzed based on experimental-statistical modeling. The results of the physico-mechanical and operational experiments confirm the rationality of using porous fillers and additives to improve certain specific properties of the final product. The so-called Monte-Carlo method is implemented for determining an optimal composition of multicomponent cement-lime light plaster, based on multivariate statistical modeling and iterative random scanning of property fields. According to the results of the computational experiment, a composition that reduces the number of expensive mixture components and improves the physical and mechanical characteristics of the resulting composition is selected. EXPERIENCE OF USING THE MONTE-CARLO METHOD IN DETERMINING OPTIMAL PLASTER COMPOSITIONS WITH IMPROVED STRENGTH PROPERTIESKeywords: cement-lime light plaster; polymer; experimental-statistical modeling; Monte-Carlo method PRONALAŽENJE OPTIMALNIH SASTAVA ŽBUKE S POBOLJŠANOM ČVRSTOĆOM METODOM MONTE-CARLOSažetak: Uzimajući u obzir činjenicu da se za moderne građevinske materijale postavljaju sve veći zahtjevi, potrebno je proširiti asortiman građevinskih materijala i poboljšati njihov višekomponentni sastav. Na bazi eksperimentalno-statističkog modeliranja analiziran je utjecaj polimernih i poroznih sastojaka (ekspandirani perlitni pijesak i karbonatno punilo -biogena vapnenačka stijena) lake cementne žbuke na fizikalno-mehanička svojstva sastava, uz uvjet jednake obradivosti. Rezultati ispitivanja fizikalno-mehaničkih i operativnih svojstva potvrdili su racionalnost upotrebe poroznih punila i aditiva za poboljšanje određenih specifičnih svojstava konačnog proizvoda. Kako bi pronašli optimalan sastav višekomponentne cementno-vapnene žbuke, provedena je Monte Carlo metoda zasnovana na višedimenzionalnom statističkom modeliranju s iterativnim slučajnim pretraživanjem polja svojstava. Prema rezultatima računskih pokusa odabiru se spojevi u kojima se smanjuje udio skupih komponenti smjese i poboljšavaju fizičko-tehnološke karakteristike dobivenog sastava.
The influence of the components of plaster mortars on their properties is considered in a lot of studies at a qualitative level without searching for optimal compositions of these multicomponent composite materials. The purpose of this study was to obtain the experimental–statistical models based on the results of the designed experiment, allowing the influence of light fillers and polymer admixtures on the properties of the mortars to be evaluated and analysed; the compositions complying with specified requirements and compromised optimally by a number of properties should be found. The quantities of fine limestone and perlite as well as of the hydroxyethyl methyl cellulose and dispersible polymer were varied in the experiment. The effective viscosity and thixotropy of the mix, compression, tensile, adhesive strength, frost resistance, and density of hardened mortars were determined for 18 compositions according to the experiment design. The obtained models have allowed the individual and synergetic effects of mix components to be evaluated. The fine perlite has turned out to have the greatest positive effect on the properties. This porous filler increases the strength while decreasing the density of the mortars. It is shown how the composition complying with specified requirements—and the best based on several properties—has been found.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.