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Rheological properties of cement pastes modified with pumice, trass and chalcedonite powder

Spychał Edyta, Vyšvařil Martin

Structure and Environment

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2023

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Vol. 15, no. 4

217--226

EN

The article presents the influence of pumice, trass and chalcedonite powder on rheological properties of cement pastes. Cement was being replaced both of additions 10% or 20% by mass and combination of pumice or trass and chalcedonite powder in the amount 5% or 10% of each of them. The main purpose of the publication was to assess the effects of chalcedonite powder with selected mineral additions in terms of rheological properties and compare them with the results obtained for pastes modified with only one of the additions. In each case, the additive or combination of additives introduced into the paste reduced the flow, compared to the result of paste without additive(s). Rheological properties varied depending on type and amount of additive(s).

PL

W artykule przedstawiono badania wpływu pumeksu, trasu oraz mączki chalcedonitowej na właściwości reologiczne zaczynów cementowych. Cement zastępowano każdym z dodatków w ilości 10% lub 20% oraz kombinacją pumeksu lub trasu z mączką chalcedonitową w ilości po 5% i 10% każdym z nich. Głównym celem pracy była ocena współdziałania mączki chalcedonitowej z wybranymi dodatkami mineralnymi w zakresie właściwości reologicznych oraz porównanie rezultatów badań z wynikami uzyskanymi dla zaczynów modyfikowanych tylko jednym z dodatków. W każdym z przypadków dodatek lub kombinacja dodatków wprowadzone do zaczynu wpłynęły na zmniejszenie rozpływu, w porównaniu do wyników uzyskanych dla zaczynu bez dodatku(ów). Właściwości reologiczne były zróżnicowane w zależności od rodzaju i ilości dodatku(ów).

2

Effects of pumice additions on thermal and mechanical behaviors of epoxy resin

Kırbaş İbrahim

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 4

art. no. e146286

EN

In this study, thermal conductivity, mechanical properties, and thermal degradation of pumice-added epoxy materials were investigated. 2%, 4%, 6%, 8%, and 10% of pumice was added to the epoxy resin (EP) % by weight. Various types of analyses and tests were conducted to determine the thermal conductivity, mechanical properties, and thermal degradation of these epoxy materials. The tests and analyses proved that the addition of pumice leads to a decrease in the thermal conductivity coefficient and density of the pure EP material. It also increases the degree of hardness. The addition of pumice had a positive effect on mechanical properties. Compared to pure EP, it increased the tensile strength, Young’s modulus, bending strength, and flexural modulus. As a result of TGA analysis it was determined that with the incorporation of pumice into the EP, its decomposition rate progressed more slowly. At 800_C, the carbon residue improved as a result of the addition of pumice.

3

The Effects of Additives to Lightweight Aggregate on the Mechanical Properties of Structural Lightweight Aggregate Concrete

Khoshvatan Mehdi, Pauraminia Majid

Civil and Environmental Engineering Reports

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2021

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Vol. 31, no. 1

139--160

EN

In the paper, the effects of different percentages of additives (perlite, LECA, pumice) on the mechanical properties of structural lightweight aggregate concrete were tested and evaluated. For the research, 14 mixing designs with different amounts of aggregate, water, and cement were made. Experimental results showed that the specific gravity of lightweight structural concrete made from a mixture of LECA, pumice, and perlite aggregates could be 25-30% lighter than conventional concrete. Lightweight structural concrete with a standard specific gravity can be achieved by using a combination of light LECA with perlite lightweight aggregates (LA) and pumice with perlite in concrete. The results indicated that LECA lightweight aggregates show more effective behavior in the concrete sample. Also, the amount of cement had a direct effect on increasing the strength regardless of the composition of LAs. The amount of cement causes compressive strength to increase. Furthermore, the stability of different experimental models increased from 156 to 345 kg m3 while increasing the amount of cement from 300 to 400 kg m3 in the mixing designs of LECA and perlite for W/C ratios of 0.3, 0.35, and 0.4. For a fixed amount of cement equal to 300 kg, the compressive strength is reduced by 4% by changing the water to cement ratio from 0.5 to 0.4. The compression ratios of strength for 7 to 28 days obtained in this study for lightweight concrete were between 0.67-0.8. rate of tensile strength to compressive strength of ordinary concretes, which is approximately 10, this ratio is about 13.5 to-17.8 in selected and optimal lightweight concretes in this research, which can be considered good indirect tensile strength for structural lightweight concretes.

4

Właściwości fizyczne pumeksu i jego zachowanie jako kruszywo grube w betonie

Caiza M., Gonzalez C., Toulkeridis T., Bonifaz H.

Cement Wapno Beton

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2018

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R. 23/85, nr 6

468--478

PL

Zastosowanie lekkiego betonu zyskało popularność i powszechną akceptację w branży budowlanej na całym świecie. Jest wiele metod wytwarzania lekkiego betonu, a do jednej należy zastosowanie pumeksu jako kruszywa grubego. Głównym celem przeprowadzonych doświadczeń było określenie właściwości fizycznych pumeksu wulkanicznego, z północno-centralnego Ekwadoru i możliwości jego stosowania jako kruszywa grubego w betonie. Próbki pumeksu, konwencjonalnego kruszywa grubego i konwencjonalnego kruszywa drobnego zbadano określając skład ziarnowy, gęstość w stanie suchym, absorpcję wody, odporność na ścieranie, zawartość wilgoci i gęstość nasypową, zgodnie z normami ASTN. Skład mieszanin obliczono zgodnie z ACI 211. Do badań przygotowano po pięć próbek walcowych z kruszywem konwencjonalnym i pumeksowym. Zbadano ich wytrzymałość na ściskanie po różnych okresach, w celu porównania właściwości betonów z kruszywem klasycznym i pumeksowym.

EN

The use of lightweight concrete has gained acceptance and popularity in the construction industry worldwide. There are many methods to create lightweight concrete, one of them is the usage of pumice as a coarse aggregate. The main objective of this study has been to experimentally determine the physical properties of volcanic pumice from north-central Ecuador, when used as a coarse aggregate in concrete. Samples of pumice, conventional coarse aggregate and conventional fine aggregate were taken in order to perform the graining, dry density, water absorption, degradation, moisture content and unit mass assays according to ASTN normative. Additionally, the proportioning of the mixture has been calculated according to ACI 211, creating five test cylinders made of hydraulic concrete with conventional aggregate and five test cylinders made of hydraulic concrete using pumice aggregate, testing their compressive strength in different time periods in order to compare the results of both proportioning afterwards.

5

Dye Removal From Textile Waste Water Through The Adsorption By Pumice Used In Stone Washing

Körlü A. E., Yapar S., Perinçek S., Yılmaz H., Bağıran C.

Autex Research Journal

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2015

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Vol. 15, no. 3

158--163

EN

Because the waste production is inevitable in almost all industries, the elimination of these wastes is a requirement in terms of environmental regulations and welfare of all the creatures in the future. In this study, the use of the waste pumice stones of a denim washing mill is intended to eliminate the pollutant by a waste material and obtain economic benefits by converting it to the adsorbent. The pollutants in the effluents obtained from three different localisations of waste water treatment system of the same factory were removed through the adsorption. The experimental studies were carried out in three different steps; characterisation of adsorbent before and after adsorption; adsorption isotherm studies and biological oxygen demand (BOD), chemical oxygen demand (COD) measurements. Characterisation studies showed that the waste pumice has almost the same structural properties with unused one except the existence of some organic residues coming from washing process. The results of adsorption studies conducted at the adsorbent concentrations changing from 5 to 35 g/l revealed that the decolourisation was initial dye-concentration dependent. According to the BOD and COD measurements, the supernatants obtained at the end of adsorption could be assumed as somewhat polluted and this result indicates that the organic impurities other than indigo were also removed through the adsorption.

6

Analiza możliwości wielokrotnego zastosowania matrycy wykonanej z pumeksu do kowalencyjnego wiązania inwertazy EC 3.2.1.26

Raducka A., Ogoński T.

Inżynieria i Aparatura Chemiczna

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2009

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Nr 3

93-94

PL

Jednym z czynników decydujących o przydatności materiału do zastosowania jako matrycy w przemysłowych procesach z użyciem immobiIzowanych enzymów jest możliwość jego wielokrotnego użycia. W pracy cy przedstawiono wyniki doświadczalnych badań przydatności pumeksu meksu do wielokrotnego wiązania inwertazy. Stwierdzono, że granulowany pumeks jest nośnikiem, który można regenerować i wielokrotnie stosować do wiązania inwertazy z Saccharomyces cerevisiae.

EN

One of the most important factors deciding which material is a suitable support for covalent binding of enzymes is the ability of that material to reutilization. In this work the matrix made from granulated pumice stone was used for baker's yeast invertase covalent immobilization. It was found that granulated pumice stone might be regenerate( and reused for invertase immobilization.

7

Chemiczna aktywacja naturalnej pucolany za pomocą stałego aktywatora

Allahverdi A., Rahmani A.

Cement Wapno Beton

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2009

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R. 14/76, nr 4

205-213

PL

Otrzymano spoiwo złożone w 77% z naturalnej pucolany pumeksowej, a w 23% z aktywatora zawierającego ponad 90% cementu portlandzkiego i niewielkie ilości substancji chemicznych złożonych z siarki i metali alkalicznych. Zbadano właściwości zaczynu i zapraw sporządzonych z tego spoiwa. Czas wiązania był zawarty w granicach od 210 minut (początek wiązania) do 300 minut (koniec wiązania). Wytrzymałość zaprawy wzrastała z około 23 MPa po 28 dniach do 45 MPa po rocznym dojrzewaniu. Badania wykazały, że opracowany aktywator pozwala na otrzymanie dobrej jakości spoiwa z naturalnej pucolany pumeksowej. Jest to spoiwo niezwykle przyjazne dla środowiska.

EN

The binder was produced consisting of 77% of natural pozzolana pumice-type and 23% of activator composed chiefly of Portland cement and small addition of chemical substances containing sulfure and alkali metals. The properties of paste and mortars prepared on the basis of this binder were investigated. Setting time of the binder was the range from 210 min (beginning of setting) to 300 minutes (final setting time). The compressive strength was 23 MPa after 28 days of hardening till 45 MPa after one year of curing. The experimental results showed that the elaborated activator gives the possibility for producing good quality binder from natural puzzolana of pumice-type. This binder is very environmental friendly.