scholarly journals Rheology, Mechanical Properties and Porosity of Ternary Alkali-Activated Binders Based on Mining Mud Waste with Waste Glass and Metakaolin

CivilEng ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 236-253
Author(s):  
Abdelhakim Benhamouda ◽  
João Castro-Gomes ◽  
Luiz Pereira-de-Oliveira
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Yield Stress ◽  
Relative Yield ◽  
Rheological Behaviour ◽  
Waste Glass ◽  
Plastic Viscosity ◽  
Rheological Parameters ◽  
Alkali Activated Binders ◽  
Alkali Activated

Alkali-activated materials have the potential to replace Portland cement in certain applications. To better understand these binders’ properties, it is relevant to study their rheological behaviour at early ages, like in the case of Portland cement paste. There are already many studies on the rheological behaviour of these materials in the available literature, using fly ash, metakaolin, and ground granulated blast furnace slag as precursors. However, this study discusses the rheological behaviour, mechanical properties, and porosity of ternary alkali-activated binders based on mining mud waste, waste glass, and metakaolin. The precursor consisted of a volume mix of 70% of tungsten mining waste mud, 15% glass waste, and 15% of metakaolin. The activator was a combination of sodium hydroxide and sodium silicate solution. Five activator/precursor (A/P) ratios (0.37, 0.38, 0.39, 0.40, and 0.4) were studied. The result showed that the activator/precursor ratio affects the rheology of paste and their rheological behaviour fit the Bingham model. The relative yield stress (g) and plastic viscosity (h) increased inversely with the A/P ratio, while the workability increased proportionally. Furthermore, some empirical models are proposed to describe the characteristic of yield stress: plastic viscosity and spread diameter versus the A/P ratio and time with a correlation between the rheological parameters and the spread diameter. The increase in A/P ratio has also followed a decrease in compressive strength in all tested samples for all the ages. As expected, an increase of the porosity accompanied the increase of the A/P ratio.

scholarly journals Evolution of flow properties, plastic viscosity, and yield stress of alkali-activated fly ash/slag pastes

2020 ◽  
Vol 5 ◽  
pp. 141-149
Author(s):  
Mohammed Fouad Alnahhal ◽  
Taehwan Kim ◽  
Ailar Hajimohammadi
Keyword(s):  
Fly Ash ◽  
Yield Stress ◽  
Plastic Viscosity ◽  
Rheological Parameters ◽  
Time Intervals ◽  
Increasing Trend ◽  
Binder Ratio ◽  
Drastic Effect ◽  
Effect On Yield ◽  
Alkali Activated

The development of cementless concrete is attracting increasing attention in practice and research to reduce both greenhouse gas emissions and energy consumption of concrete. Alkali-activated materials (AAMs) are one of the viable alternatives to replace Portland cement due to their lower CO2 emissions. This study investigated the evolution of rheological parameters of alkali-activated fly ash/slag pastes as a function of time. Flowability and rheological measurements were carried out to determine the fluidity, plastic viscosity, and yield stress at different time intervals. The effects of the slag content, the concentration of SiO2 in the activator, and the solution/binder ratio were considered. Based on the results, the yield stress and plastic viscosity followed an increasing trend over time coinciding with a reduction in the paste fluidity. The plastic viscosity of AAM pastes was in the range of 1.3–9.5 Pa.s and 2.6–28.9 Pa.s after 5 min and 45 min of mixing, respectively. Given the same alkali activator, the higher content of slag the paste had, the higher yield stress the paste showed. In addition, this paper confirmed that the SiO2/Na2O ratio in the activator had no significant effect on yield stress, but a drastic effect of this ratio was found on the plastic viscosity of the paste.

scholarly journals Preliminary Study of the Rheological and Mechanical Properties of Alkali-activated Concrete Based on Tungsten Mining Waste Mud

2020 ◽  
Author(s):  
Abdelhakim Benhamouda ◽  
João Castro-Gomes
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Portland Cement ◽  
Rheological Behaviour ◽  
Coarse Sand ◽  
Mining Waste ◽  
Binder Phase ◽  
Portland Cement Concrete ◽  
Alkali Activated Concrete ◽  
Alkali Activated

The rheological properties of Portland cement (PC) concrete have been extensively studied and compared with those of alkali-activated concrete (AAC). This study discusses the effect of the liquid to solid ratio on the rheological and mechanical properties of AAM concrete, based on mining waste mud as the binder phase, and compares them with those of Portland cement concrete (PCC). The AAM concrete studied is a mix of coarse aggregate 6/15, two types of sand (finer and coarse sand), and a precursor. The precursor is a mix of 70% tungsten mining waste mud, 15% waste glass and 15% metakaolin. This mix was activated by a combination of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) and the PCC was a mix of the same aggregate but with cement as binder and water as a liquid. The activator/precursor ratio was studied 0.5, 0.52, 0.54, 0.56 and 0.58. The results obtained show a similar rheological behaviour between AAC and PCC, the workability affected by L/S increases with the increasing ratio L/S in AAC and for L/S=0.5 slump was 6 cm and was 16 cm for L/S =0.58. Regarding the mechanical properties, the results obtained in 7 days showed similar performance in AAC and PCC. The compressive strength also decreases with the increasing of L/S, in AAC with L/S=0.5 the compressive strength was 15.9 MPa and for L/S =0.58 was 10.5. Keywords: Tungsten mining waste, Rheology, Mechanical properties, Portland cement, alkali-activated concrete

Influence of Ground Slag on the Rheology of Mortar

2013 ◽  
Vol 438-439 ◽  
pp. 67-71
Author(s):  
Qian Qian Zhang ◽  
Jian Zhong Liu ◽  
Jia Ping Liu
Keyword(s):  
Film Thickness ◽  
Specific Surface ◽  
Yield Stress ◽  
Surface Area ◽  
Specific Surface Area ◽  
Water Film ◽  
Plastic Viscosity ◽  
Rheological Parameters ◽  
Water Film Thickness ◽  
Binder Ratio

The effects of ground slag with different specific surface area on the rheology of mortar at water-binder ratio of 0.25, 0.28 and 0.30 were investigated, and the combined effects of packing density and solid surface area on the rheology of mortar were evaluated in terms of the water film thickness. The results show that with the increasing of specific surface area of slag (220 m2/kg-784 m2/kg), plastic viscosity and yield stress decrease. The correlations of yield stress and plastic viscosity to the water film thickness are basically linear with high correlation R2 values. The action of the ground slag on the rheology of mortar can be characterized by water film thickness, and with the increasing of water film thickness the rheological parameters decrease.

scholarly journals MICROESTRUTURA E PROPRIEDADES FÍSICAS E MECÂNICAS DE CIMENTO PORTLAND TIPO II ÁLCALI-ATIVADO / MICROSTRUCTURE AND PHYSICAL AND MECHANICAL PROPERTIES OF ALKALI-ACTIVATED TYPE II PORTLAND CEMENT

2020 ◽  
Vol 6 (11) ◽  
pp. 84929-84951
Author(s):  
Luccas Mansur Feuchard ◽  
Cléo Márcio de Araújo Santana ◽  
Eliane Fernandes Côrtes Pires ◽  
Fernando Luiz Barbuda de Abreu ◽  
Elie Chahdan Mounzer ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Physical And Mechanical Properties ◽  
Type Ii ◽  
Alkali Activated

scholarly journals Design of portable rheometer with new vane geometry to estimate concrete rheological parameters

2016 ◽  
Vol 23 (3) ◽  
pp. 347-355 ◽  
Author(s):  
Hamza SOUALHI ◽  
El-Hadj KADRI ◽  
Tien-Tung NGO ◽  
Adrien BOUVET ◽  
François CUSSIGH ◽  
...  
Keyword(s):  
Yield Stress ◽  
Coefficient Of Variation ◽  
Test Procedure ◽  
Plastic Viscosity ◽  
Rheological Parameters ◽  
Construction Site ◽  
Wide Range ◽  
Mineral Additions ◽  
High Plastic ◽  
Rheometer Test

This paper presents the development of a portable vane rheometer to estimate concrete plastic viscosity and yield stress. The apparatus can be used not only in laboratory but also on construction site. In this study, new blade geometry was proposed to minimize the effect of segregation of concrete during testing, and also to expand the wide range of concrete work­ability with a slump of approximately from 7 cm to fluid concrete, and concrete with high plastic viscosity such as concrete with mineral additions. The used blade (U shaped and reversed) allows reducing the vibration of the apparatus, and ob­taining more stable measurements. The obtained results permit validating the rheometer test procedure and confirmed that the results are reliable, with a low coefficient of variation of 9% for repetitive test and of 5.8% for reproductive tests.

Influence of Fructose and Sucrose on Small and Large Deformation Rheological Behaviour of Heated Amioca Starch Dispersions

2004 ◽  
Vol 10 (1) ◽  
pp. 51-57 ◽  
Author(s):  
D. B. Genovese ◽  
V. M. Acquarone ◽  
K. -S. Youn ◽  
M. A. Rao
Keyword(s):  
Yield Stress ◽  
Large Deformation ◽  
Heating Temperature ◽  
Ageing Time ◽  
Rheological Behaviour ◽  
Angular Frequency ◽  
Rheological Parameters ◽  
Static Yield ◽  
Pasting Temperature ◽  
Dynamic Yield

Effect of sucrose or fructose on the rheological behaviour of gelatinized 5% w/w amioca starch dispersions (GSDs), was studied by small and large deformation rheological techniques. Storage (G0) and loss (G00) moduli as a function of angular frequency (o), and shear stress (s) as a function of shear rate (_) data were obtained on GSDs with: 0, 30 and 60% w/w sugars. Magnitudes of Herschel–Bulkley yield stress (0-HB) were determined from – _ data. Using the vane method, the static yield stress (0s), the dynamic yield stress (0d) and the shear modulus (G) were determined. Effect of pasting temperature and ageing time were also studied by the vane method. Addition of sugars produced an increase in all rheological parameters except 0d, suggesting that sugars increased the strength of the internal bonds or cohesiveness of the GSDs; in general, fructose was slightly more effective than sucrose. Equivalent parameters: G0 and G, and 0-HB and 0s showed good agreement. Decreasing the heating temperature increased G. GSDs with fructose showed a clear increase in 0s and G with ageing time.

scholarly journals An overview of the utilisation of Fe-rich residues in alkali-activated binders: Mechanical properties and state of iron

2021 ◽  
pp. 129900
Author(s):  
Vitalii Ponomar ◽  
Juho Yliniemi ◽  
Elijah Adesanya ◽  
Katja Ohenoja ◽  
Mirja Illikainen
Keyword(s):  
Mechanical Properties ◽  
Alkali Activated Binders ◽  
Alkali Activated

Alkali Activated Binders Based on Metakaolin

2015 ◽  
Vol 1 ◽  
pp. 200
Author(s):  
Laura Sele ◽  
Diana Bajare ◽  
Girts Bumanis ◽  
Laura Dembovska
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Water Absorption ◽  
Raw Materials ◽  
Sodium Silicate Solution ◽  
Total Porosity ◽  
Lead Silicate ◽  
Cement Production ◽  
Alkali Activated Binders ◽  
Alkali Activated

<p>According to research conducted in last 25 years, alkali activated binders have been considered as one of the most progressive alternative binders, which can effectively replace Portland cement. Production of alkali activated binders differs from the Portland cement production and is associated with lower CO2 emissions. The use of recycled industrial by-products and wastes is also possible, what corresponds to the future guidelines and principles of sustainable binder production in the world.<br />The aim of this study was to create innovative alkali activated binders by using secondary raw materials, which will be different from the ones described in the scientific literature – alkali activated binders with porous structure. Raw materials used for the binders were metakaolin containing waste, waste from aluminium scrap recycling factory and recycled lead-silicate glass; solid contents were activated with modified sodium silicate solution with an addition of sodium hydroxide.<br />The physical properties of alkali activated binders, such as density, water absorption, open and total porosity, were determined and flexural and compressive strength of hardened alkali-activated binders were tested at the age of 28 days. Durability was examined by sulphate resistance test, which was performed according to SIA 262/1, appendix D: applicability and relevance for use in practice. 40x40x160 mm prismatic specimens were used for expansion measurement and determination of compressive strength. <br />The open porosity of obtained materials was up to 45%, density from 380 to 1720 kg/m3, compressive strength up to 29,8 MPa, water absorption 6 – 114 wt.%. After analysing the results from the sulphate test it was concluded that glass additive reduced the alkali activated binder resistance to sulphate attack.</p>

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