scholarly journals X-ray diffraction of concrete composites of high structural strength and density

2021 ◽  
Vol 22 (4) ◽  
pp. 746-749
Author(s):  
Oleksandr Sumariuk ◽  
Ihor Fodchuk ◽  
Volodymyr Romankevych
Keyword(s):  
Compressive Strength ◽  
Structural Strength ◽  
Cement Stone ◽  
Qualitative Composition ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
Factors Affecting ◽  
X Ray ◽  
Calcium Hydrosilicates ◽  
Main Factors

Аn analysis of the structure formation of concrete composites, compressive strength of which exceeds 120 MPa and a quantitative analysis of their qualitative composition and hydration products by X-ray diffraction, x-ray spectral analysis. The main factors affecting the physicomechanical parameters of the complex of various nanofillers and the formation of a denser cement stone structure, which mainly includes calcium hydrosilicates, calcium silicate hydroaluminates and hydroaluminates of various basicity, are studied.

Improvement of Wood-Cement Composition Properties with Microsilica Additive

2020 ◽  
Vol 992 ◽  
pp. 162-167
Author(s):  
E.Yu. Gornostaeva ◽  
N.P. Lukuttsova ◽  
D.I. Dryazgov
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Silicon Dioxide ◽  
Cement Hydration ◽  
Cement Stone ◽  
Hydration Products ◽  
Maximum Increase ◽  
Calcium Hydrosilicates ◽  
Calcium Silicates ◽  
Composition Properties

The properties and microstructure of wood-cement compositions (WCC) with microsilica (MS) additive for the manufacture of small-pieces wall products are studied. The extreme dependences of mean density, thermal conductivity and compressive strength on the content of microsilica additive are established. The mechanism of microsilica effect on wood-cement compositions is offered. Two interrelated factors (chemical and physical) could be distinguished at that. The first factor includes mainly the interaction of silicon dioxide with lime having released during hydration of calcium silicates, i.e. pozzolatic process. The second factor lies in the compaction of wood-cement compositions and the cement stone structure by means of cement hydration products and silica particles. It is established that introducing 20% of microsilica in the composition results in the maximum increase in ultimate compression strength (3 times). It can be explained not only by forming calcium hydrosilicates, uniformly and densely covering the wood aggregate, but by compacting effect of spherical microsilica inclusions, filling the space between the new cement stone formations and wood aggregate.

scholarly journals Effect of Metakaolin on Strength and Efflorescence Quantity of Cement-Based Composites

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Tsai-Lung Weng ◽  
Wei-Ting Lin ◽  
An Cheng
Keyword(s):  
Compressive Strength ◽  
Image Analysis ◽  
Portland Cement ◽  
Detrimental Effect ◽  
Cement Mortar ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
Replacement Ratio ◽  
X Ray ◽  
Scanning Electron

This study investigated the basic mechanical and microscopic properties of cement produced with metakaolin and quantified the production of residual white efflorescence. Cement mortar was produced at various replacement ratios of metakaolin (0, 5, 10, 15, 20, and 25% by weight of cement) and exposed to various environments. Compressive strength and efflorescence quantify (using Matrix Laboratory image analysis and the curettage method), scanning electron microscopy, and X-ray diffraction analysis were reported in this study. Specimens with metakaolin as a replacement for Portland cement present higher compressive strength and greater resistance to efflorescence; however, the addition of more than 20% metakaolin has a detrimental effect on strength and efflorescence. This may be explained by the microstructure and hydration products. The quantity of efflorescence determined using MATLAB image analysis is close to the result obtained using the curettage method. The results demonstrate the best effectiveness of replacing Portland cement with metakaolin at a 15% replacement ratio by weight.

scholarly journals CHANGES IN THE STRUCTURAL AND PHASE COMPOSITION OF CEMENT CONCRETE DURING MICROBIOLOGICAL CORROSION

2021 ◽  
Vol 6 (11) ◽  
pp. 106-113
Author(s):  
K. Strokin ◽  
D. Novikov ◽  
V. Konovalova ◽  
N. Kasiyanenko
Keyword(s):  
Compressive Strength ◽  
Phase Composition ◽  
Portland Cement ◽  
Cement Stone ◽  
Cement Concrete ◽  
Microbiological Corrosion ◽  
Crystalline Phases ◽  
X Ray ◽  
Calcium Hydrosilicates ◽  
Black Mold

The article considers the change in the structural and phase composition of cement stone made of Portland cement of the CEM I 42.5 N brand in the process of bacterial and fungal corrosion during 6 months when humidified. The X-ray images of cement stone show peaks that characterize the non-hydrated components of Portland cement alite, belite, tricalcium aluminate, four-calcium aluminoferrite and gypsum. By the method of X-ray phase analysis, it is found that during microbiological corrosion, the content of all phases of cement stone decreases. The aspergillus niger van Tieghem fungi have a stronger effect on the structural and phase composition of cement stone. Fungal microorganisms destroy the crystalline phases and absorb amorphous phases – calcium hydrosilicates C-S-H (I) and C-S-H (II) and tobermorite. When bacteria Bacillus subtilis affects the cement stone, the content of the calcite phase increases, which is a product of corrosion, while the action of black mold reduces the intensity of CaCO3 peaks. A decrease in the content of low-base calcium hydrosilicates and ettringite, as well as other crystalline phases, leads to a decrease in the compressive strength of the cement stone. During 6 months of microbiological corrosion of cement concrete under conditions of constant wetting, the compressive strength decreases by about 35 %.

Effect of Hydration Products Transformation for Compressive Strength of Autoclaved Silicate Products

2012 ◽  
Vol 204-208 ◽  
pp. 3644-3647
Author(s):  
Chang Jun Ke ◽  
Shu Ying Wang ◽  
Jun Li Liu
Keyword(s):  
Compressive Strength ◽  
Steam Pressure ◽  
Diffraction Peak ◽  
Saturated Steam ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
Spectroscopy Analysis ◽  
X Ray ◽  
Diffraction Peaks ◽  
The Relationship

the relationship between hydration products transformation and the compressive strength was studied with X-ray diffraction, infrared spectroscopy analysis. The results showed, 0.505nm hydrogarnets diffraction peaks weakened and 0.183nm CSH diffraction peak enhanced with different autoclaved time under 1.2MPa saturated steam pressure. 0.505nm hydrogarnets diffraction peak enhanced under lower saturated steam pressure for autoclaving 6h, then weaken under higher saturated steam pressure. And 0.183nm CSH diffraction peaks enhanced with different saturated steam pressure for autoclaving 6h. During autoclaving, hydrogarnet translate into Al-substituted calcium silicate hydrate (C-S-H). Transformation of hydration products is favorable for compressive strength of autoclaved sample.

scholarly journals Effect of Naphthalene-Based Superplasticizer and Polycarboxylic Acid Superplasticizer on the Properties of Sulfoaluminate Cement

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 662
Author(s):  
Yonghua Wu ◽  
Qiqi Li ◽  
Guoxin Li ◽  
Shiying Tang ◽  
Mengdie Niu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
Hydration Products ◽  
Polycarboxylic Acid ◽  
X Ray Diffraction ◽  
Calcium Sulfoaluminate Cement ◽  
X Ray ◽  
Initial Setting Time ◽  
Calcium Sulfoaluminate ◽  
Initial Setting

In order to study what the effect of superplasticizers on the setting time, fluidity and compressive strength of calcium sulfoaluminate cement (CSA) a naphthalene-based superplasticizer (BNS) and a polycarboxylic acid superplasticizer (PC) were selected to interact with CSA pastes and ye’elimite, respectively. X-ray diffraction (XRD), thermogravimetric (TG) analysis and scanning electron microscopy (SEM) analytical methods were used to investigate the class, amount and microstructure of the CSA pastes and ye’elimite pastes hydration products under the effect of the superplasticizers. The results showed that the addition of BNS can promote ettringite generation and thus improve the early compressive strength. As the addition of BNS increased from 0.8 wt% to 2.0 wt%, the initial setting time was prolonged 10 min, the final setting time was prolonged 7 min, the 5 min fluidity was improved from no fluidity to 220 mm. However, as the addition of PC increased from 0.08 wt% to 0.20 wt%, the setting time of the PC just changed within 3 min; the 5 min fluidity increased from 110 mm to 195 mm and no 15 min fluidity at all was observed. AS seen by SEM, it can be stated that generated ettringite under the addition of PC was layered and lacking bonding, and its morphology changed from rod-like to flake-like, leading to a decrease in early compressive strength.

Utilization of Desulfuration Residues in Non-Autoclaved Aerated Concrete

2011 ◽  
Vol 250-253 ◽  
pp. 707-710
Author(s):  
Fang Xian Li ◽  
You Zhi Chen ◽  
Qi Jun Yu ◽  
Jiang Xiong Wei
Keyword(s):  
Compressive Strength ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Bulk Density ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
Autoclaved Aerated Concrete ◽  
Aerated Concrete ◽  
Scanning Electron

Desulfuration residues were used as aggregate to produce Non-autoclaved aerated concrete. The effects of water-hinder ratio, casting temperature on the gas forming behavior, and those of desulfuration residue content on the compressive strength and bulk density of aerated concrete were investigated. The types of the hydration products and the microstructure of Non-autoclaved aerated concrete with desulfuration residue were investigated by means of X-ray diffraction and scanning electron microscope. Results show that the optimum replacement amount was determined as 50% and at this rate the compressive strength, bulk density of Non-autoclaved aerated concrete were measured as 2.83 MPa and 543 kg/m3. The hydration products of Non-autoclaved aerated concrete with desulfuration residue are C2SH (A) and C2SH (B) along with ettringite and hydrogarnet phases.

Experimental Researches on Microstructure of Nanometer Silicon and Cement-Stabilized Soils

2011 ◽  
Vol 94-96 ◽  
pp. 358-364 ◽  
Author(s):  
Li Feng Wang
Keyword(s):  
Compressive Strength ◽  
Calcium Silicate ◽  
Unconfined Compressive Strength ◽  
Silicon Powder ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcium Silicate Hydrates ◽  
Stabilized Soil ◽  
Experimental Researches

Unconfined compressive strength of various mixing proportions and ages of nanometer silicon and cement-stabilized soils（NCSS） are tested ,and the rules of compressive strength are got. Hydration products and microstructures of NCSS are discussed by means of XRD and SEM technology, and microstructural mechanisms of NCSS are analyzed. Results show that nanometer silicon powder added to cement-stabilized soil(CSS) can sharply improve the compressive strength of CSS. More Calcium silicate hydrates(C-S-H) and other hydration products can be produced in the process of secondary reaction of cement and water added nanometer silicon powder. X ray diffraction tests indicate the kinds and quantities of C-S-H increase with nanometer silicon contents. Strengths of NCSS are bettered by increasing jointed strength changed from edge-edge, edge-face connectios to cementation connections affected by increasing hydration products. Large pores of NCSS can be greatly decreased by adding nanometer silicon powder, and hydration products filling in the pores make NCSS more dense materials.

Effect of Curing Time on the Pore Structure of the Portland Cement Concrete

2010 ◽  
Vol 44-47 ◽  
pp. 2592-2596
Author(s):  
Wei Lun Wang ◽  
Peng Liu
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Pore Structure ◽  
Mercury Intrusion Porosimetry ◽  
Curing Time ◽  
Hydration Products ◽  
Portland Cement Concrete ◽  
X Ray Diffraction ◽  
Cement Concrete ◽  
X Ray

In this paper, the influence of curing time on the compressive strength and pore structure of the Portland cement concrete was investigated. The phase composition and morphology of hydration products of Portland cement were analyzed with X-ray diffraction (XRD). In addition, the porosity and pore distribution of the concrete were also researched using mercury intrusion porosimetry (MIP), surface area and porosity analyzer (BET). The results show that the influence of curing time on the compressive strength and pore structure of the concrete is obvious. With curing time increasing, the compressive strength of the concrete increased and the porosity decreased. The corresponding fractal dimension of the pore and the microstructure were changed, as well. With time increasing, more hydration products were produced.

scholarly journals THE INTERACTION BETWEEN [Pt(µ-Cl)(Safrole-1H)]2 AND 1,3-DIISOPROPYLBENZIMIDAZOLIUM BROMIDE IN THE PRESENCE OF Ag2O

2020 ◽  
Vol 58 (6) ◽  
pp. 728
Author(s):  
Nguyen Thi Thanh Chi
Keyword(s):  
Single Crystal ◽  
Nmr Spectra ◽  
Molar Ratio ◽  
Trans Position ◽  
Dimeric Complex ◽  
X Ray Diffraction ◽  
Factors Affecting ◽  
X Ray ◽  
In Trans ◽  
Main Factors

The interaction of the dimeric complex [Pt(µ-Cl)(Saf)]2 (1) (Saf: deprotonated safrole) with the salt iPr2-bimy·HBr in the presence of Ag2O in acetone solvent was studied. The obtained products were mixed complexes of [PtCl(Saf)(iPr2-bimy)] (2) and [PtBr(Saf)(iPr2-bimy)] (3) with different molar ratio (PI, PII, PIII)  depended on the used molar ratio of 1:salt:Ag2O. In the case of this ratio being 1:2:1.1, the mixture PI with 75% for the complex 2 was obtained. When concentration of the salt was increased, the product was PII with the molar ratio of 2 : 3 of 1 : 3. However, when both the salt and Ag2O were increased at the same time, 2 and 3 in PIII had equal molar proportions. The two main factors affecting the 2 : 3 molar ratio are the different solubility of AgCl and AgBr and the different coordinating ability of Cl- and Br- ligands. The structure of 2 and 3 was determined by 1H NMR spectra and single crystal X-ray diffraction. The results reveal that Saf in 2 and 3 coordinates with Pt(II) via C=Colefinic and C5 of benzene ring. Meanwhile, iPr2-bimy coordinates with Pt(II) through CNCN and is in trans-position compared with the C=Colefinic bond.

scholarly journals The influence of complex additives based on calcined clays and carbonate fillers on hydration products composition of blended cement stone

2021 ◽  
Vol 274 ◽  
pp. 04004
Author(s):  
Elizaveta Ermilova ◽  
Zagira Kamalova
Keyword(s):  
Blended Cement ◽  
Cement Industry ◽  
Cement Stone ◽  
Content Increase ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Calcined Clay ◽  
Calcium Hydrosilicates ◽  
Kaolinitic Clay

One of the most effective and recognizable way to solve energy and resource consumption problems in cement industry is the development of blended Portland cement with different combinations of mineral additives. The development of complex additives based on combination of calcined clays and limestone is one of the promising directions. The aim of this work was to study the influence of complex additives based on calcined kaolinitic clay with kaolinite content of 80 % and limestone with calcite content of 99 % on the blended cement stone hydration products at the age of 28 days. Using X-ray diffraction and differential scanning calorimetry the composition of blended cement stone hydration products was studied. It is established that the introduction of 20 % of the complex additive based on calcined clay and limestone leads to a significant decrease of the portlandite content, increase in the number of new growths in form of low-calcium hydrosilicates and calcium hidrocarboalumosilicates, stabilization of ettringiteand calcium hydrocarbosilicates in amorphous phase, that significantly increases the compressive strength. This effect was amplified due to the additional alumina provided by calcined clay reaction.

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