Physical and chemical characterization of technogenic pozzolans for the application in blended cements

Záleská, Martina; Pavlíková, Milena; Pavlík, Zbyšek; Jankovský, Ondřej; Pokorný, Jaroslav; Tydlitát, Vratislav; Svora, Petr; Černý, Robert

doi:10.1016/j.conbuildmat.2017.11.021

Cited by 71 publications

(27 citation statements)

References 41 publications

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“…The powder density was evaluated as well. The determination of pozzolanic activity was performed using modified Chapelle test [22,23], which is specified in French norm NF P 18-513 (2009) [24]. The principle of the method is based on the reaction of 1 g of tested powder material with 2 g CaO in the water at 80°C during 24 hours.…”

Section: Aggregate and Silica Vp4 Characterizationmentioning

confidence: 99%

Lightweight Concrete Made With Waste Expanded Polypropylene-Based Aggregate and Synthetic Coagulated Amorphous Silica

Záleská¹

2018

Ceramics - Silikaty

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Recycled plastic aggregate can be used as an alternative material to produce lightweight concrete with low environmental impact. Polypropylene is one of the least recycled post-consumer plastics. In the present study we focused at waste expanded polypropylene (EPP) aggregate that is used for partial replacement of natural aggregate to produce lightweight cementbased composites. Coagulated silica was used as admixture for improvement of dispersion of EPP particles in the cementbased matrix. At first, natural and EPP aggregates were examined. Coagulated silica was characterized by SEM, EDS, XRF, particles size distribution and pozzolanic activity. Analysis of the microstructure of lightweight concrete was performed using an optical microscope, SEM imaging and EDS. For the developed lightweight concrete, basic physical, mechanical and hygric properties were examined. Specific attention was paid to thermal properties. The results show, using of plastic waste aggregate led to a sufficient mechanical resistance, whereas the thermal insulation performance of the developed concrete was markedly improved. Composite with incorporated PP waste aggregates was found to be prospective material for nonstructural applications in building industry, which allows the development of buildings with optimum energy performance as well as reduce the growing environmental impact of waste polymers and saving the natural aggregates.

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Section: Aggregate and Silica Vp4 Characterizationmentioning

confidence: 99%

Lightweight Concrete Made With Waste Expanded Polypropylene-Based Aggregate and Synthetic Coagulated Amorphous Silica

Záleská¹

2018

Ceramics - Silikaty

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“…This parameter is mainly a useful initial criterion for concrete manufacturers, but it is just a qualitative parameter without sufficient detail which will not be complicated enough to assess the effectiveness of a pozzolan. Záleská et al suggested a much suitable parameter, called pozzolan effectiveness coefficient (PEC), which offers a quantitative assessment defined as follows:

PEC ((), x) = \frac{f_{c}^{'} ((), normalP x) - ((), 1 - \frac{x}{100}) . f_{c}^{'} ((), R)}{f_{c}^{'} ((), R) . \frac{x}{100}}

where

f_{c}^{'}

is the compressive strength, x is the mass percentage of pozzolan in the combined cement, P x is the paste with PC and x % of pozzolan and R is the reference paste with just PC. Classification of a pozzolan using PEC is given in Table , which its negative value indicates that the material cannot be considered as a pozzolan and it acts as a filler, while the positive value of PEC reveals the pozzolanic reaction of the material and its greater value shows a higher pozzolanic property.…”

Section: Resultsmentioning

confidence: 99%

“…The current standard characterization test methods provide only incomplete information for most SCMs and natural pozzolanic materials, including those, which are most commonly used. Three sets of methods, which assess pozzolanic materials, are the fundamental physical and chemical prerequisites, reactivity in ideal conditions, and performance in a blend with PC . Natural pozzolanic materials, which mostly need only are conditioning of particle characteristics by sieving and grinding .…”

Section: Introductionmentioning

confidence: 99%

Introduction of a mineral powder as a type of natural cementitious material in concrete: An experimental program

Fazilati

Golafshani

2019

Structural Concrete

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The principal air pollution within the concrete enterprise is cement in charge of roughly 5-7% of manufactured CO 2 emissions. For reducing CO 2 emissions and improving concrete properties, new types of natural cementitious materials have been served in concrete throughout the last two decades. In this study, a mineral powder (MP) as a type of supplementary cementitious material has been introduced and the chemical and physical properties of this MP and mechanical properties of the produced concrete were investigated. In this regard, the total number of 24 concrete mixes with 0 to 40% replacement of Portland cement (PC) with MP was designed. Concrete samples were tested for compressive, flexural, splitting tensile strengths, and elastic modulus at the age of 7, 28, 42, and 90 days. The experimental results indicate that the maximum compressive, flexural, and splitting tensile strengths are obtained by replacing about 5% PC with MP. Finally, the amount of CO 2 emission reduction for concrete specimens containing MP was evaluated. K E Y W O R D S CO 2 emissions, mechanical properties, mineral powder, supplementary cementitious material

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“…Using the measurement results from the bulk-density and matrix-density tests, the total open porosity f (%) was calculated. 10 The expanded combined uncertainty of the total open porosity was 3 %.…”

Section: Measurement Methodsmentioning

confidence: 99%

Properties of high-performance fiber-reinforced concrete after thermal treatment at high temperatures

Pavlík¹,

Fořt²,

Pavlíková³

et al. 2019

Mater. Tehnol.

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A complex analysis of the effect of a high-temperature load on the parameters of a high-performance fiber-reinforced concrete (HPFRC) is presented. The HPFRC containing steel fibers was exposed to temperatures of up to 1000°C. In order to reveal the effect of the elevated temperatures on the concrete performance, its basic physical, mechanical, hygric and thermal properties were determined after the thermal treatment. To observe physical and chemical processes in the HPFRC as a function of temperature, a simultaneous thermal analysis (STA) and a thermodilatometry analysis (TDA) were used. The high-temperature exposure led to an increase in the porosity and pore size and to a significant decrease in the mechanical strength. The values of hygric and thermal properties correspond to the changes in the material structure after the thermal treatment. STA and TDA data showed structural changes of the studied material and allowed identification of critical temperatures for its damage. Keywords: fiber-reinforced concrete, high-temperature exposure, thermal strain, structural changes Avtorji predstavljajo kompleksno analizo vpliva termi~nih obremenitev na parametre visokokakovostnega, z vlakni oja~anega betona (HPFRC). Preiskovani beton, ki je vseboval jeklena vlakna, so izpostavili visokim temperaturam do 1000°C. Po toplotni obdelavi betona so ugotavljali vpliv visokih temperatur na njegove fizikalne, mehanske in hidro-termalne lastnosti. Fizikalne in kemijske procese HPFRC v odvisnosti od temperature so ugotavljali s pomo~jo simultane termi~ne analize (STA) in termodilatometrije (TDA). Termi~na obremenitev preiskovanega betona je povzro~ila pove~anje velikosti por in posledi~no pove~anje celokupne poroznosti ter znatno zmanj{anje njegove mehanske trdnosti. Vrednosti hidro-termalnih lastnosti po termi~ni obremenitvi betona so se spremenile skladno s spremembami v strukturi materiala. Rezultati STA in TDA analiz ka`ejo na strukturne spremembe preiskovanega materiala in omogo~ajo identifikacijo kriti~nih temperatur za~etka njegovih po{kodb. Klju~ne besede: z jeklenimi vlakni oja~an beton, visoko temperaturna obremenitev, termi~ne deformacije, strukturne spremembe

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Physical and chemical characterization of technogenic pozzolans for the application in blended cements

Cited by 71 publications

References 41 publications

Lightweight Concrete Made With Waste Expanded Polypropylene-Based Aggregate and Synthetic Coagulated Amorphous Silica

Lightweight Concrete Made With Waste Expanded Polypropylene-Based Aggregate and Synthetic Coagulated Amorphous Silica

Introduction of a mineral powder as a type of natural cementitious material in concrete: An experimental program

Properties of high-performance fiber-reinforced concrete after thermal treatment at high temperatures

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