Microstructure and Mechanism of Concrete Using Inorganic Silicate Admixture

2013 ◽  
Vol 284-287 ◽  
pp. 1235-1241
Author(s):  
Si Yu Zou ◽  
Ran Huang ◽  
An Cheng ◽  
Wei Ting Lin ◽  
Jia Liang Chang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Porous Structure ◽  
Cement Hydration ◽  
Microscopic Analysis ◽  
Positive Influence ◽  
Composition Analysis ◽  
Hydration Products ◽  
Chemical Composition Analysis ◽  
Porosity Measurements

The study evaluates the properties of concrete mixed with inorganic silicate admixture. The admixture was used in proportions of 3%, 5%, and 7% of the weight of the cement. We performed tests on compressive strength and elastic modulus to evaluate the mechanical properties of concrete. Results show that the addition of the inorganic silicate admixture has a positive influence on the mechanical properties of concrete, with the best results obtained with 3% admixture. MIP porosity measurements determined that the addition of inorganic silicate admixture increased the density of the porous structure. SEM microscopic analysis revealed many needle-like protrusions into the porous structure of concrete. XRF chemical composition analysis indicated that these structures comprised mainly Na2O and SiO2. Can with cement hydration products Ca(OH)2 bring in Chemical reaction. Inferred pore structure Within be C-S-H gel of needle-like protruding structure. it can improve the main cause of mechanical properties of concrete.

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.

Study on Properties of Wollastonite Micro Fiber Reinforced Mortar

2013 ◽  
Vol 785-786 ◽  
pp. 151-156 ◽  
Author(s):  
Xiao Deng ◽  
Wen Yang ◽  
Xiao Qin Liu ◽  
Bao Jun Cheng ◽  
Tong Liu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Glass Fiber ◽  
Comparative Studies ◽  
Cement Hydration ◽  
Three Dimensional ◽  
Sem Analysis ◽  
Fiber Content ◽  
Hydration Products ◽  
Fiber Reinforced

The paper carried out comparative studies on the workability, mechanical properties and chloride permeation resistance of wollastonite micro fiber mortar and alkali resistant glass fiber（ARGF） mortar. The results show that the mechanical properties and chloride permeation resistance of wollastonite micro fiber mortar improve significantly. The mechanical properties of wollastonite micro fiber mortar have greater advance in 90°C humidity. The SEM analysis results show that wollastonite micro fiber can form three-dimensional skeleton in the mortar, and combine closely with cement hydration products. This can make the structure of hardened paste denser and lead to excellent properties of mortar. Meanwhile, the compressive strength of wollastonite micro fiber mortar with wollastonite micro fiber content 30%(by mass) is close to ARGF mortar with ARGF content 1.5% (in volume), but the chloride permeation resistance of wollastonite micro fiber mortar is much better.

Analysis on Welding Crack of Subcritical Power Station Boiler Platen Superheater Header

2012 ◽  
Vol 251 ◽  
pp. 446-449 ◽  
Author(s):  
Yan Ting Feng ◽  
Xiang Feng Zheng ◽  
Xue Xia Xu ◽  
Guo Zhen Dong ◽  
Yong Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Welding Residual Stress ◽  
Composition Analysis ◽  
Power Station ◽  
Element Analysis ◽  
Test Chemical ◽  
Welding Defects ◽  
Chemical Composition Analysis ◽  
Leakage Failure ◽  
Power Station Boiler

Welding crack analysis was carried out on tee joint crack of boiler platen superheater header (12Cr1MoV) of subcritical power station applying finite element analysis,microanalysis, mechanical properties test, chemical composition analysis, metallography examination and SEM observation etc. Results indicated that the improper structure, the original welding defects, higher welding heat input, excessive welding residual stress and improper heat treatment led to cold crack and reheat crack ,then induced to the leakage failure while operating.the welding crack originated at the original defects, connected with reheat cracks during propagation and led to leakage finally.

Fracture Failure Analysis of N80 Q Marine Casing

2013 ◽  
Vol 318 ◽  
pp. 331-335
Author(s):  
Hong Zhang ◽  
Quan Luo ◽  
Xu Hui Liu ◽  
Peng Wang ◽  
Ding Feng
Keyword(s):  
Mechanical Properties ◽  
Fracture Analysis ◽  
Metallographic Analysis ◽  
Composition Analysis ◽  
Service Environment ◽  
Fracture Failure ◽  
Completion Process ◽  
Casing Pipe ◽  
Chemical Composition Analysis ◽  
Mechanical Properties Testing

The 13-3/8〞casing of a well was bent down and broken off in the marine development completion process. The cause for the fracture is systematically analyzed by means of chemical composition analysis, mechanical properties testing, macro and micro fracture analysis and metallographic analysis. The results indicate that, the heterogeneity of the casing material and large oxide metallurgical inclusions found in fracture place severely reduce the properties of the material, which lead to the failure of casing pipe in bad service environment.

Failure Analysis of Hot Clamp Induced Cracking on Hydrogen Reformer Outlet Pigtail Tubes

2019 ◽  
Vol 795 ◽  
pp. 340-345
Author(s):  
Luo Wei Cao ◽  
Guo Shan Xie ◽  
Min Zhen Zhao
Keyword(s):  
Mechanical Properties ◽  
Failure Analysis ◽  
Boundary Segregation ◽  
Grain Boundary Segregation ◽  
Composition Analysis ◽  
Impurity Atoms ◽  
Chemical Composition Analysis ◽  
Mechanical Properties Testing ◽  
Metallurgical Evaluation ◽  
Reformer Tube

Failure analysis of the hot clamped outlet pigtail tubes connected with hydrogen reformer tube in refineries has been carried out. In this paper, hot clamp induced cracking on Incoloy 800HT outlet pigtail tube of a reformer unit is studied by microscopic observation and mechanical properties testing. Metallurgical evaluation and chemical composition analysis have been performed on both hot clamped cracking tube and no cracking one. Results indicated that the most important parameter affecting the high temperature brittleness of pigtails are the Ni/Cr value, surface grain size and impurity atoms grain boundary segregation.

scholarly journals Crossover Effect in Cement-Based Materials: A Review

2019 ◽  
Vol 9 (14) ◽  
pp. 2776 ◽  
Author(s):  
Sumra Yousuf ◽  
Payam Shafigh ◽  
Zainah Ibrahim ◽  
Huzaifa Hashim ◽  
Mohammad Panjehpour
Keyword(s):  
Compressive Strength ◽  
Construction Industry ◽  
Building Materials ◽  
Cement Hydration ◽  
Curing Temperature ◽  
Future Research ◽  
Hydration Products ◽  
Crossover Effect ◽  
Cement Based Materials ◽  
Mineral Compositions

Cement-based materials (CBMs) such as pastes, mortars and concretes are the most frequently used building materials in the present construction industry. Cement hydration, along with the resulting compressive strength in these materials, is dependent on curing temperature, methods and duration. A concrete subjected to an initial higher curing temperature undergoes accelerated hydration by resulting in non-uniform scattering of the hydration products and consequently creating a great porosity at later ages. This phenomenon is called crossover effect (COE). The COE may occur even at early ages between seven to 10 days for Portland cements with various mineral compositions. Compressive strength and other mechanical properties are important for the long life of concrete structures, so any reduction in these properties is of great concern to engineers. This study aims to review existing information on COE phenomenon in CBMs and provide recommendations for future research.

Influence of Wollastonite or Plant Fiber on Performance of Autoclaved Cement Concrete

2011 ◽  
Vol 99-100 ◽  
pp. 692-695
Author(s):  
Tie Quan Ni ◽  
Li Zhang ◽  
Bing Yuan
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Bending Strength ◽  
Composition Analysis ◽  
X Ray Diffraction ◽  
Cement Concrete ◽  
Plant Fiber ◽  
X Ray ◽  
Strength Change ◽  
Chemical Composition Analysis

The influence of wollastonite or plant fiber on the property of autoclaved cement concrete is studied by chemical composition analysis, X-ray diffraction analysis, scanning electron microscopy and energy spectrum analysis. The results showed that the two fibers were benefit to bending strength of autoclaved cement concrete. The suitable content of wollastonite was about 15% of cement mass, and the increased amplitude of flexural strength was more than 30% and the compressive strength slightly increased for autoclaved cement concrete admixed wollastonite. The optimal content of plant fiber was about 1.5% of cement mass, the increased amplitude of the flexural strength was more than 20%, and the compressive strength change of autoclaved cement concrete was not significant for autoclaved cement concrete admixed plant fiber.

scholarly journals Effect of Sodium Aluminate Dosage as a Solid Alkaline Activator on the Properties of Alkali-Activated Slag Paste

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Bin Chen ◽  
Jun Wang ◽  
Jinyou Zhao
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Setting Time ◽  
Sodium Aluminate ◽  
Hydration Reaction ◽  
Hydration Products ◽  
Alkali Activated Slag ◽  
Alkaline Activator ◽  
Activated Slag ◽  
Alkali Activated

Extensive research into alkali-activated slag as a green gel material to substitute for cement has been done because of the advantages of low-carbon dioxide emissions and recycling of industrial solid waste. Alkali-activated slag usually has good mechanical properties, but the too fast setting time restricted its application and promotion. Changing the composition of alkaline activator could optimize setting time, usually making it by adding sodium carbonate or sodium sulfate but this would cause insufficient hydration reaction power and hinder compressive strength growth. In this paper, the effect of sodium aluminate dosage as an alkaline activator on the setting time, fluidity, compressive strength, hydration products, and microstructures was studied through experiments. It is fair to say that an appropriate amount of sodium aluminate could obtain a suitable setting time and better compressive strength. Sodium aluminate provided enough hydroxyl ions for the paste to promote the hydration reaction process that ensured obtaining high compressive strength and soluble aluminium formed precipitate wrapped on the surface of slag to inhibit the hydration reaction process in the early phase that prolonged setting time. The hydration mechanism research found that sodium aluminate played a key role in the formation of higher cross-linked gel hydration products in the late phase of the process. Preparing an alkali-activated slag with excellent mechanical properties and suitable setting time will significantly contribute to its application and promotion.

scholarly journals Analysis and Research on the Cause of Wind Turbine Blade Bolt Fracture

2021 ◽  
Vol 2133 (1) ◽  
pp. 012028
Author(s):  
Feng Yun ◽  
Jun Liu ◽  
Chunyu Liu ◽  
Xiaochun Zhao
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Stress Concentration ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Wind Farm ◽  
Composition Analysis ◽  
Chemical Composition Analysis ◽  
Mechanical Properties Testing ◽  
Load Impact

Abstract In 2019, inspection personnel of a wind farm went to the tower and found that a total of 6 bolts of blades in the hub of a wind turbine had broken and failed. In order to find out the cause of fracture, the fracture bolt was comprehensively detected and analyzed by means of appearance morphology analysis, chemical composition analysis, mechanical properties testing, microstructure testing and fracture micro-area analysis. The results show that the main reasons for the bolt fracture are as follows: under the action of the bolt’s constantly changing and repeated wind load impact and the alternating load caused by blade rotation during the operation of the fan, the crack source is formed along the bottom of the thread with serious stress concentration and expands in fatigue mode until the whole fracture fails.

The Preparation and Pozzolanic Activity of Metakaolin Admixtures

2013 ◽  
Vol 539 ◽  
pp. 230-234 ◽  
Author(s):  
Bao Min Wang ◽  
Yuan Zhang ◽  
Ming Li
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Cement Paste ◽  
Cement Mortar ◽  
Heat Treating ◽  
Ratio Method ◽  
Strength Ratio ◽  
Hydration Products ◽  
Burning Temperature ◽  
Optimum Proportion

The optimum burning temperature of kaolinite and the optimum proportion of metakaolin (MK) in cement paste were studied by the compressive strength ratio method. Metakaolin was obtained at different burning temperature of 700°C, 750°C, 800°C and 850°C for 4 hours, and mixed into cement with the incorporation of 0, 5wt.%, 10wt.%, 15wt.% and 20wt.%. At last, the mechanical properties were researched. The influence of different burning temperature on hydration products of metakaolin cement mortar were analyzed. The results show that the compressive strength ratio of metakaolin cement mortar and the metakaolin pozzolanicity reach the maximum when the metakaolin obtained by heat treating of 750°C, the optimum proportion of metakaolin in cement is 10%~15%.

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