scholarly journals MICROSCOPIC AND PHASE ANALYSIS OF CEMENT PASTE CONTAINING WASTE MICRONIZED MARBLE POWDER

2018 ◽  
Vol 15 ◽  
pp. 94-98
Author(s):  
Zdeněk Prošek ◽  
Pavel Tesárek ◽  
Jan Trejbal
Keyword(s):  
Electron Microscopy ◽  
Phase Composition ◽  
Portland Cement ◽  
Phase Analysis ◽  
Cement Paste ◽  
Reference Sample ◽  
Hydration Process ◽  
Cement Composites ◽  
Marble Powder ◽  
The Impact

The article focuses on the impact of waste marble powder on resulting cement composites. We investigate of influence waste marble powder on the hydration process and hence the resulting phase composition. The hydration process was investigated using calorimetry and phase composition of the resulting composite by electron microscopy. The results are compared with a reference sample composed of Portland cement.

The Impact of Basic Minor Oxides on the Clinker Formation

2017 ◽  
Vol 908 ◽  
pp. 3-9 ◽  
Author(s):  
Theodor Staněk ◽  
Petr Sulovský
Keyword(s):  
Electron Microscopy ◽  
Phase Composition ◽  
Portland Cement ◽  
Current Knowledge ◽  
Cement Clinker ◽  
Laboratory Conditions ◽  
Optical And Electron Microscopy ◽  
Composition And Structure ◽  
Portland Cement Clinker ◽  
The Impact

In laboratory conditions, the effect of minor oxides – MgO and SO3 on formation of Portland cement clinker was observed. The research extended the current knowledge about the effect of these oxides on phase composition and structure of clinker and on alite polymorphism. Mainly means of optical and electron microscopy were used for the research.

Formation of bulk samples from the Ti3AlC2 MAX-phase powder by selective laser sintering

2021 ◽  
Vol 2 ◽  
pp. 27-33
Author(s):  
M. G. Krinitcyn ◽  
◽  
I. A. Firsina ◽  
A. V. Baranovskiy ◽  
M. P. Ragulina ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Phase Composition ◽  
Phase Analysis ◽  
Selective Laser Sintering ◽  
Structural Phase ◽  
Laser Sintering ◽  
Max Phase ◽  
X Ray ◽  
Phase Study ◽  
Complex Structural

Bulk samples from the powder of the MAX-phase Ti3AlC2 were obtained by selective laser sintering (SLS). A complex structural-phase study was carried out using optical and electron microscopy, as well as X-ray phase analysis, the elemental and phase composition of the samples was determined, and the morphology of the initial powders and bulk SLS samples was described. This study allowed to describe the elemental and phase composition, as well as the morphology of both the initial powders and bulk SLS samples. Modes of selective laser sintering are established at which the maximum presence of the MAX-phase in the samples after SLS is observed.

scholarly journals Effect of nano-SnO2 on early-age hydration of Portland cement paste

2019 ◽  
Vol 11 (6) ◽  
pp. 168781401985194 ◽  
Author(s):  
Jianping Zhu ◽  
Genshen Li ◽  
Ruijie Xia ◽  
Huanhuan Hou ◽  
Haibin Yin ◽  
...  
Keyword(s):  
Portland Cement ◽  
Cement Paste ◽  
Cement Hydration ◽  
Cementitious Materials ◽  
Hydration Process ◽  
Strength Development ◽  
Early Age ◽  
Test Machine ◽  
Portland Cement Paste ◽  
Scanning Electron

Nanomaterial, as a new emerging material in the field of civil engineering, has been widely utilized to enhance the mechanical properties of cementitious material. Nano-SnO2 has presented high hardness characteristics, but there is little study of the application of nano-SnO2 in the cementitious materials. This study mainly investigated the hydration characteristics and strength development of Portland cement paste incorporating nano-SnO2 powders with 0%, 0.08%, and 0.20% dosage. It was found that the early-age compressive strength of cement paste could be greatly improved when nano-SnO2 was incorporated with 0.08% dosage. The hydration process and microstructure were then measured by hydraulic test machine, calorimeter, nanoindentation, X-ray diffraction, scanning electron microscope, and mercury intrusion porosimetry. It was found that the cement hydration process was promoted by the addition of nano-SnO2, and the total amount of heat released from cement hydration is also increased. In addition, the addition of nano-SnO2 can promote the generations of high density C-S-H and reduce the generations of low density C-S-H indicating the nucleation effect of nano-SnO2 in the crystal growth process. The porosity and probable pore diameter of cement paste with 0.08% nano-SnO2 were decreased, and the scanning electron microscopic results also show that the cement paste with 0.08% nano-SnO2 promotes the densification of cement microstructure, which are consistent with the strength performance.

scholarly journals Microstructure–Property Relationship of Polyurethane Foams Modified with Baltic Sea Biomass: Microcomputed Tomography vs. Scanning Electron Microscopy

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5734
Author(s):  
Paulina Kosmela ◽  
Jan Suchorzewski ◽  
Krzysztof Formela ◽  
Paweł Kazimierski ◽  
Józef Tadeusz Haponiuk ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Baltic Sea ◽  
Thermal Insulation ◽  
Reference Sample ◽  
Microcomputed Tomography ◽  
Polyurethane Foams ◽  
Relationship Of ◽  
The Impact ◽  
Scanning Electron

In this paper, novel rigid polyurethane foams modified with Baltic Sea biomass were compared with traditional petro-based polyurethane foam as reference sample. A special attention was focused on complex studies of microstructure, which was visualized and measured in 3D with high-resolution microcomputed tomography (microCT) and, as commonly applied for this purpose, scanning electron microscopy (SEM). The impact of pore volume, area, shape and orientation on appearance density and thermal insulation properties of polyurethane foams was determined. The results presented in the paper confirm that microcomputed tomography is a useful tool for relatively quick estimation of polyurethane foams’ microstructure, what is crucial especially in the case of thermal insulation materials.

The Effect of Boron and its Compounds on Setting of Portland Cement

2014 ◽  
Vol 1000 ◽  
pp. 16-19 ◽  
Author(s):  
Jiří Kratochvíl ◽  
Tomáš Opravil ◽  
Pavel Diviš
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Portland Cement ◽  
Boric Acid ◽  
Cement Paste ◽  
Kinetics Of

The aim of this work is to study the influence of boron and its compounds, boric acid and borax, on the hydration of Portland cement. The samples – cement paste modified by the addition of boron, borax and boric acid in different concentrations were prepared. The results are obtained from the evaluation of calorimetric curves, mechanical properties and phase composition. The goal is to describe the kinetics of targeted retarded process of hydration and to find such addition which would suspend the setting of boron modified system entirely. The comparison of effects of each boron-containing compound is based on its concentration and on its kind.

scholarly journals Implementation of natural and artificial materials in Portland cement

2020 ◽  
Vol 74 (3) ◽  
pp. 147-161
Author(s):  
Pero Dabic ◽  
Damir Barbir
Keyword(s):  
Portland Cement ◽  
Cementitious Materials ◽  
Environmental Benefits ◽  
Supplementary Cementitious Materials ◽  
Hardened Concrete ◽  
Cement Composites ◽  
Artificial Materials ◽  
Waste Container ◽  
Almost All ◽  
The Impact

For the preparation of modern cement and concrete, supplementary cementitious materials (SCM) have become essential ingredients. The technical, economic and environmental advantages of using SCM have become unquestionable. The main technical reasons for their use are the improvement of the workability of fresh concrete and durability of hardened concrete. Actually, SCM affect almost all concrete properties, while environmental and economic reasons may be more significant than technical reasons. These ingredients can reduce the amount of Portland cement used in cement composites, resulting in economic and environmental benefits. In addition, many of the SCM are industrial by-products, which can otherwise be considered as waste. This paper presents a literature review of the present knowledge on the impact of natural zeolite, waste construction brick and waste container glass on physical, chemical and mechanical properties of Portland cement as the most commonly used cement in the world.

Determination the Availability of Chromium from Powdered Cement Composites Containing Blast Furnace Slag

2015 ◽  
Vol 244 ◽  
pp. 246-251
Author(s):  
Jozef Oravec ◽  
Adriana Eštoková
Keyword(s):  
Blast Furnace ◽  
Portland Cement ◽  
Hexavalent Chromium ◽  
Blast Furnace Slag ◽  
Reference Sample ◽  
The Other ◽  
Waste Materials ◽  
Cement Composites ◽  
Environmental Indicator ◽  
Furnace Slag

Nowadays, cement composites often contain a certain amount of waste materials, which can lead to increased heavy metals leaching. Important environmental indicator of the suitability of concrete is a leachability of chromium. In this paper, concrete samples containing special admixture based on the blast furnace slag as replacement of Portland cement (65%, 75%, 85% and 95%, respectively) as well as reference sample containing only a Portland cement were analyzed. Availability test was used to study the maximum chromium leaching from finely ground cement composites samples. The findings revealed that the leachability of hexavalent chromium from the samples containing 65 and 75 wt. % of slag-based additive was 4.59 and 1.70 times higher, respectively then the leachability of hexavalent chromium from the samples containing no slag. On the other hand, the 85 and 95 wt. % slag-containing-samples provided the Cr (VI) leachability by 26 and 41 % lower than the samples without any slag addition. Regarding the slag containing samples, the higher content of slag-based additive was in concrete sample, the lower leachability of Cr (VI) was detected.

Mechanical Properties and Microstructure of Graphene-Cement Composites

2017 ◽  
Vol 748 ◽  
pp. 295-300 ◽  
Author(s):  
Rui Shuang Jiang ◽  
Bao Min Wang
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Compressive Strength ◽  
Cement Paste ◽  
Control Sample ◽  
Cement Composites ◽  
X Ray Diffraction ◽  
Visible Spectroscopy ◽  
X Ray ◽  
Transmission Electron

In this work, two type graphene were dispersed in aqueous solution via sonication, and graphene nanoplatelets (GP) and graphene oxide (GO) were characterized by means of ultraviolet visible spectroscopy (UV-vis), X-ray diffraction (XRD) and transmission electron microscopy (TEM). In addition, the effects of different graphene (GP and GO) on mechanical properties and microstructure of cement-based materials were investigated via filed emission scanning electron microscopy (FESEM). The results suggested that the incorporation of GP and GO both improved the flexural and compressive strength of cement, and the GP had a more prominent impact on the strengths of cement, compared with GO. The flexural and compressive strength of cement increased up to 23.5% and 7.5% with 0.05 wt% GP, respectively. FESEM analysis indicated that the microstructure of GP-cement paste was similar to that of control sample without graphene, whereas, a few flower-like crystals were generated in GO-cement paste. This work could provide a new understanding for further researches of graphene-cement composites.

Deterioration of Cement Composites with Silica Fume Addition due to Chemical and Biogenic Corrosion Processes

2015 ◽  
Vol 227 ◽  
pp. 190-193 ◽  
Author(s):  
Adriana Eštoková ◽  
Martina Kovalcikova ◽  
Alena Luptáková
Keyword(s):  
Comparative Study ◽  
Portland Cement ◽  
Sulphuric Acid ◽  
Silica Fume ◽  
Calcium Ions ◽  
Reference Sample ◽  
Experimental Studies ◽  
Concrete Sample ◽  
Cement Composites ◽  
Silicon Ions

The paper is aimed at comparative study of resistance of Portland cement composites with addition of silica fume as durability increasing factor in various aggressive environments (sulphuric acid with pH 4, the medium of activated bacteria and the cultivating medium without bacteria) during 150 days under model laboratory conditions. Experimental studies confirmed: the leaching of silicon ions calculated to 1 g of concrete sample affected with bacteriaAcidithiobacillusthiooxidanswas 2.5 times lower (31.78 mg/g of sample) for concrete sample with silica fume addition comparing to concrete sample of ordinary CEM I Portland cement without any additives (82.98 mg/g of sample). The highest concentration of calcium ions released (60.808 mg/g of sample) was observed for reference sample without silica fume addition placed in the cultivating medium. Silica fume based concrete samples were found to have better performance in terms of calcium ions leaching for all environments and silicon ions leaching.

scholarly journals Effect of Delaminated MXene (Ti3C2) on the Performance of Cement Paste

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Jianping Zhu ◽  
Genshen Li ◽  
Chunhua Feng ◽  
Libo Wang ◽  
Wenyan Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Cement Paste ◽  
Cement Hydration ◽  
Hydration Heat ◽  
Hydration Process ◽  
Cement Matrix ◽  
Cement Composites ◽  
Hydrated Cement ◽  
Hydration Products

Delaminated MXene was incorporated into cement to improve the properties of cement composites, and its effects on the hydration process, microstructures, and mechanical properties were investigated, respectively. The investigation results showed that delaminated MXene was well-dispersed in the cement matrix and significantly reinforced the compressive strength of cement, especially when the addition is 0.01 wt%. Meanwhile, the total hydration heat of cement hydration and the quantity of hydration products were increased with the addition of delaminated MXene. In addition, the formation of HD C-S-H gel was promoted, and the microstructure of hydrated cement became more compact.

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