scholarly journals The Use of Geopolymers for the Disposal of Asbestos-containing Materials

2020 ◽  
Vol 322 ◽  
pp. 01014
Author(s):  
Michał Łach ◽  
Katarzyna Lichocka ◽  
Maria Hebdowska-Krupa ◽  
Wei-Ting Lin ◽  
Kinga Korniejenko
Keyword(s):  
Compressive Strength ◽  
Literature Review ◽  
Appropriate Technology ◽  
Cement Composites ◽  
Fly Ashes ◽  
Asbestos Fibers ◽  
Geopolymer Matrix ◽  
Asbestos Cement ◽  
Strength Tests ◽  
Made In

Asbestos is widely known as a hazardous material and can contribute to many diseases. Its removal and neutralization are complicated, it requires proper preparation and the use of appropriate technology. Immobilization of asbestos materials in geopolymers seems to be one of the alternatives to its storage in landfills. However, this requires several studies confirming the possibility of asbestos immobilization in geopolymers. Also, asbestos dust contains silicon and aluminum, which may prove useful in the production of geopolymers. The paper presents research results regarding the possibility of using geopolymers based on fly ashes for neutralizing asbestos. An up-to-date literature review on the technology of managing asbestos-containing products is presented. As a result of the research, partial usefulness of geopolymerization technology for binding and neutralizing waste with asbestos was found. The research was carried out using waste asbestos-cement composites. Mixtures based on geopolymers were made in which ground asbestos material was introduced in an amount of 30, 50 and 70% by weight. Compressive strength tests have shown that geopolymers with the addition of asbestos have compressive strength: over 34 MPa for a composition containing 30% of asbestos material and about 14 MPa for a composition containing 70% of asbestos material. SEM observations have shown that asbestos fibers do not dissolve in the geopolymer production process and they can still be a threat if the geopolymer matrix is damaged.

scholarly journals Alkali-Activated Fly Ashes: Influence of Curing Conditions on Mechanical Strength

2018 ◽  
Vol 3 (2) ◽  
pp. 57-67
Author(s):  
Filipe Almeida ◽  
Nuno Cristelo ◽  
Tiago Miranda ◽  
Castorina S. Vieira ◽  
Maria De Lurdes Lopes ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Relative Humidity ◽  
Mechanical Strength ◽  
Research Groups ◽  
Fly Ashes ◽  
Curing Conditions ◽  
Alkaline Activation ◽  
Strength Tests ◽  
Higher Temperature ◽  
Alkali Activated

Alkaline activation of fly ashes is a procedure that enables an alternative binder which has been receiving much interest by several research groups particularly on the manufacturing of mortars and concretes. The properties of the materials that are developed during the alkaline activation are influenced by the curing conditions (temperature and relative humidity). Another relevant facet related to the curing procedures is the possibility of carbonation occur, which may have an impact on the mechanical strength of the alkaline cements. In this research, several sets of curing conditions were tested to understand which one results in a higher strength and reveals carbonation. Uniaxial compressive strength tests were conducted to assess mechanical behavior. The outcome suggests that higher temperature and low relative humidity yields higher mechanical strength.

scholarly journals Influence of fly-ashes on properties of ordinary concretes

2016 ◽  
Vol 48 (1) ◽  
pp. 79-94 ◽  
Author(s):  
Gabriela Rutkowska ◽  
Krzysztof Wiśniewski ◽  
Marek Chalecki ◽  
Mirosława Górecka ◽  
Kamil Miłosek
Keyword(s):  
Sustainable Development ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Building Materials ◽  
Waste Recycling ◽  
Fly Ashes ◽  
Depth Of Penetration ◽  
Air Content ◽  
Water Absorbability ◽  
Made In

Abstract Influence of fly-ashes on properties of ordinary concretes. Care of the environment in accordance with the principles of sustainable development introduces the possibility and need for waste recycling. The construction and building materials industry has the greatest potential for reuse of waste. The article presents the results of investigations of selected properties (consistency, water absorbability, compressive strength and tensile strength after 28 and 56 days of curing, depth of penetration) of ordinary concretes and concretes containing fly-ashes - calcareous and siliceous ash − in their composition. To make the samples, the Portland cement CEM I 42.5 R and natural aggregate with graining of 0-16 mm were used. The concrete with siliceous and calcareous admixtures was made in three lots where the ash was added in the quantity of 15, 20 and 30% of the cement mass. After the tests, it was stated that the fly-ash admixture does not increase the air content in the mix, it increases the compressive strength in time and the siliceous ash improves the splitting tensile strength.

Ladle Slag as an Admixture in Cement Composites

2020 ◽  
Vol 838 ◽  
pp. 53-58
Author(s):  
Radek Papesch ◽  
Tomáš Dvorský ◽  
Vojtěch Václavík ◽  
Jakub Svoboda ◽  
Lukáš Klus
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Hardened Cement ◽  
Cement Composites ◽  
Mechanical Parameters ◽  
Secondary Product ◽  
Ladle Slag ◽  
Strength Tests ◽  
Percentage Share

The research was dealing use of ladle slag and its impact on the physical and mechanical parameters of hardened cement composites. The goal was to find a suitable percentage share of ladle slag used as an admixture. The results of compressive strength tests show the possibility of replacement of a significant amount of cements with a specific secondary product. A decrease in compressive strength of about 8% after 28 days has to be taken into account when using Portland cement CEM I 42.5R and a 10% replacement with ladle slag.

Effects of Quarry Dust as Partial Sand Replacement on Compressive Strength and Crack Profile of Cement Composites

2015 ◽  
Vol 819 ◽  
pp. 399-404
Author(s):  
M. Madzura ◽  
M.N. Mazlee ◽  
Shamsul Baharin Jamaludin
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Cement Composite ◽  
Cement Composites ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Strength Tests ◽  
Experimental Works ◽  
Quarry Dust ◽  
Crack Profile

This research presents the findings of experimental works in terms of mechanical properties and crack profile of cement composites containing quarry dust at different percentages as a partial sand replacement. The compositions of quarry dust were varied from 10 to 20 wt. % and were mixed into five different ratios. It was found that 0.45 water cement ratio was suitable to mix all proportions and values of slump were observed have been increased with the increasing percentage of quarry dust in cement composites. The compressive strength tests were carried out and the results showed that the compressive strength decreased at each 2.5 percent interval of quarry dust at 7 and 28 days of curing. However, the strength developments of cement composites were increased corresponding to the ages of curing. The crack profiles of cement composites have been analyzed to investigate the strength developments of the cement composites. According to the results, the cracks in the specimens were in shearing pattern at 10 and 12.5 wt. % of quarry dust in cement composites. Meanwhile, as the contents of quarry dust at 15, 17.5 and 20 wt. %, the specimens failed in shearing and splitting patterns. According to the findings of compressive strength and crack profile, the contents of quarry dust as a partial sand replacement is 12.5 wt. % were more suitable to be utilized in cement composite

Microstructure and Characterizations of Portland-Carbon Nanotubes Pastes

2008 ◽  
Vol 55-57 ◽  
pp. 549-552 ◽  
Author(s):  
T. Nochaiya ◽  
P. Tolkidtikul ◽  
Pisith Singjai ◽  
Arnon Chaipanich
Keyword(s):  
Carbon Nanotubes ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Portland Cement ◽  
Aging Time ◽  
Sem Analysis ◽  
Cement Composites ◽  
Strength Tests ◽  
Tga Analysis

This research studied microstructure and characterizations of Portland cement with carbon nanotubes (CNTs) which were used as an additive material at 0 %, 0.5 % and 1 % by weight of cement. The compressive and flexural strength tests of mixes were conducted using water/cement ratios (w/c) of 0.5. Samples of mixes were selected for SEM analysis and then ground for TGA analysis. The results show that the compressive strength and flexural strength at all aging time of Portland-CNTs cement composites was higher than that of control mix. Microstructure results show that CNTs was filled in pores between matrix phases to show denser phase and TGA graphs show similar phases to PC mix.

scholarly journals 3D IMAGING OF INDIVIDUAL PARTICLES: A REVIEW

2012 ◽  
Vol 31 (2) ◽  
pp. 65 ◽  
Author(s):  
Eric Pirard
Keyword(s):  
Literature Review ◽  
Digital Imaging ◽  
Systems Analysis ◽  
3D Imaging ◽  
Materials Science ◽  
Recent Literature ◽  
Three Dimensional ◽  
Shape Estimation ◽  
Individual Particles ◽  
Made In

In recent years, impressive progress has been made in digital imaging and in particular in three dimensional visualisation and analysis of objects. This paper reviews the most recent literature on three dimensional imaging with a special attention to particulate systems analysis. After an introduction recalling some important concepts in spatial sampling and digital imaging, the paper reviews a series of techniques with a clear distinction between the surfometric and volumetric principles. The literature review is as broad as possible covering materials science as well as biology while keeping an eye on emerging technologies in optics and physics. The paper should be of interest to any scientist trying to picture particles in 3D with the best possible resolution for accurate size and shape estimation. Though techniques are adequate for nanoscopic and microscopic particles, no special size limit has been considered while compiling the review.

Preparation and Mechanical Properties of Polyethylene-Portland Cement Composites

2009 ◽  
Vol 1242 ◽  
Author(s):  
Rivas-Vázquez L.P. ◽  
Suárez-Orduña R. ◽  
Valera-Zaragoza M. ◽  
Máas-Díaz A. De la L. ◽  
Ramírez-Vargas E.
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Portland Cement ◽  
Plastic Waste ◽  
Cement Composites ◽  
Compression Tests ◽  
Standard Samples ◽  
Cement Ratio ◽  
Reinforcing Fibers ◽  
Waste Polyethylene

ABSTRACTThe effects of waste polyethylene aggregate as admixture agent in Portland cement at different addition polyethylene/cement ratios from 0.0156 to 0.3903 were investigated. The reinforced samples were prepared according the ASTM C 150 Standard (samples of 5 × 5 × 5 cm). The reinforcing fibers were milling at a size of 1/25 in diameter, form waste and used them to evaluate the effects in mechanical properties in cement-based composites. The evaluation of polyethylene as additive was based on results of density and compression tests. The 28-day compressive strength of cement reforced with plastic waste at a replacement polyethylene/cement ratio of 0.0468 was 23.5 MPa compared to the control concrete (7.5 MPa). The density of cement replaced with polyethylene varies from 2.114 (0% polyethylene) to 1.83 g/cm3 by the influence of polyethylene.

scholarly journals Influence of the surface treatment of tire rubber residues added in mortars

2008 ◽  
Vol 1 (2) ◽  
pp. 113-120 ◽  
Author(s):  
A. C. Marques ◽  
J. L. Akasaki ◽  
A. P. M. Trigo ◽  
M. L. Marques
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Surface Treatment ◽  
Water Absorption ◽  
Modulus Of Elasticity ◽  
Tire Rubber ◽  
Flow Test ◽  
Made In

In this work it was evaluated the influence tire rubber addition in mortars in order to replace part of the sand (12% by volume). It was also intended to verify if the tire rubber treatment with NaOH saturated aqueous solution causes interference on the mechanical properties of the mixture. Compressive strength, splitting tensile strength, water absorption, modulus of elasticity, and flow test were made in specimens of 5cmx10cm and the tests were carried out to 7, 28, 56, 90, and 180 days. The results show reduction on mechanical properties values after addition of tire rubber and decrease of the workability. It was also observed that the tire rubber treatment does not cause any alteration on the results compared to the rubber without treatment.

Measurement of high-alumina cement-calcium carbonate reactions using DTA

Clay Minerals ◽  
1984 ◽  
Vol 19 (5) ◽  
pp. 857-864 ◽  
Author(s):  
H. G. Midgley
Keyword(s):  
Compressive Strength ◽  
Calcium Carbonate ◽  
High Alumina ◽  
Curing Time ◽  
Lower Strength ◽  
Alumina Cement ◽  
High Alumina Cement ◽  
Strength Tests ◽  
The Stability

AbstractHydrating high-alumina cement will react with calcium carbonate to form the complex mineral calcium carboaluminate hydrate, 3CaO.Al2O3.CaCO3.12H2O. This mineral is reported to be capable of providing strength in concrete and so may provide an alternative to the minerals normally found in the hydration of high-alumina cement, which may under certain conditions convert to other minerals with a loss in strength. Some doubt has been cast on the stability of calcium carboaluminate hydrate and it has been found that in hydrated high-alumina cement, calcium carboaluminate hydrate decomposes at temperatures in excess of 60°C. Cube compressive strength tests on high-alumina cement and high-alumina cement-calcium carbonate pastes have shown that the latter have a lower strength than pastes made with high-alumina cement alone. When cured at 50°C the high-alumina cement-calcium carbonate pastes show a loss in strength with curing time. Cements made with the high-alumina cement-calcium carbonate mixture always have a lower strength than those made with high-alumina cement alone and so no advantage is gained from their use.

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