scholarly journals Influence of activation of microsphere and latex base addition on mechanical properties of concrete

2019 ◽  
Author(s):  
Wioletta Dobaczewska ◽  
Wojciech Kubissa ◽  
Karol Prałat ◽  
Patryk Tomczak
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Environmental Conditions ◽  
Scientific Research ◽  
Resistance Test ◽  
Building Industry ◽  
Freeze Thaw ◽  
Basic Properties ◽  
Concrete Mixtures ◽  
Tensile Splitting Strength

In a modern civil engineering, it is important to erection construction in extremely complicated and difficult environmental conditions. Additives and admixes to concrete enable to achieved higher mechanical properties of concrete mixtures. This operation causes, the constructions accomplish durability in various environmental conditions. In the article, authors described scientific research made on concrete with additives: latex based polymer and microspheres. The tested additives were used in to different proportion each and they were combined with each other. The aim of research was to determine influence this two additives on compressive strength after 28 days, after 90 days, a tensile splitting strength, a sorptivity, a freeze-thaw resistance and a compressive strength on the specimens after freeze-thaw resistance test. Received results clearly show decrease in compressive strength of the modified concrete mixtures. The specimens prepared without additives achieved the highest compressive strength results.The researchers observed also increasing liquidity of concrete mixtures and decreasing sorptivity of hardener concrete under the influence of latex based polymer. The knowledge of basic properties of microspheres from co-combustion of coal is fundamental to its effect usage of building industry.

scholarly journals Enhancement of concrete performance via mixed limestone and granite powders

2021 ◽  
Author(s):  
Hao Zeng ◽  
Jin Zhang ◽  
Kai Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Phase Composition ◽  
Synergistic Effect ◽  
Environmental Conditions ◽  
Erosion Resistance ◽  
Hydration Products ◽  
Freeze Thaw ◽  
Composite Mixture ◽  
Durability Of Concrete

Abstract The granite and limestone powders are commonly exploited as a replacement for cement; however, the effects of different mixing dosages of them on the mechanical properties and durability of concrete have not been scrutinized carefully. Under different environmental conditions, the compressive strength of the specimens is measured using cube compressive, splitting tensile, freeze-thaw cycles, and sulfate immersion tests. The phase composition of hydration products and microstructure is evaluated by SEM scanning analysis. The results indicate that the composite mixture of granite and limestone powders shows a complementary synergistic effect and improves the mechanical properties, freeze-thaw resistance, and sulfate erosion resistance of the concrete. The best values for the mechanical properties and freeze-thaw resistance are obtained when the dosages of granite and limestone powders in order are 10% and 5%. For the case of granite and limestone powders equal to 10% and 15%, respectively, the best sulfate erosion resistance is reported.

Physical Properties of Building Blocks from Hemp Shives Aggregate and Cementitious Binder, Manufactured in the Expanded Clay (Vibro Pressing) Production Line

2017 ◽  
Vol 908 ◽  
pp. 118-122 ◽  
Author(s):  
Giedrius Balčiūnas ◽  
Viktor Kizinievič ◽  
Justinas Gargasas
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Physical Properties ◽  
Production Line ◽  
Scientific Literature ◽  
Building Blocks ◽  
Freeze Thaw ◽  
Cementitious Binder ◽  
Pressing Technology

Scientific literature mostly aims at investigation of composites with fibre hemp shives (FHS) aggregate and lime binder, although, such materials are characterised by pretty low mechanical properties. In order to obtain higher mechanical properties of a composite, it is appropriate to use cementitious binder. This work investigates physical properties of blocks from hemp shives aggregate and cementitious binder, manufactured in the expanded clay production line using vibro pressing technology. Following properties of the blocks are determined: freeze-thaw resistance, compressive strength, thermal conductivity and density. Thermal resistance according to EN ISO 6946 for the block with cavities is calculated as well. It is found that compressive strength of FHS-cement blocks may be up to 3.18 MPa when the density is of ~850 kg/m3 and thermal conductivity up to 0.135 W/(m∙K). It is found as well that the decrease of compressive strength is 8.7% after 25 freeze-thaw cycles.

Compressive Strength of Concrete from Lightweight Bubbles Aggregate

2015 ◽  
Vol 754-755 ◽  
pp. 348-353 ◽  
Author(s):  
Norlia Mohamad Ibrahim ◽  
Leong Qi Wen ◽  
Mustaqqim Abdul Rahim ◽  
Khairul Nizar Ismail ◽  
Roshazita Che Amat ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Compressive Strength ◽  
Natural Resources ◽  
Concrete Structure ◽  
Concrete Mixture ◽  
New Materials ◽  
Concrete Mixtures ◽  
Compressive Strength Of Concrete

Compressive strength of concrete is the major mechanical properties of concrete that need to be focused on. Poor compressive strength will lead to low susceptibility of concrete structure towards designated actions. Many researches have been conducted to enhance the compressive strength of concrete by incorporating new materials in the concrete mixture. The dependencies towards natural resources can be reduced. Therefore, this paper presents the results of an experimental study concerning the incorporation of artificial lightweight bubbles aggregate (LBA) into cementations mixture in order to produce comparable compressive strength but at a lower densities. Three concrete mixtures containing various percentages of LBA, (10% - 50% of LBA) and one mixture used normal aggregate (NA) were prepared and characterized. The compressive strength of LBA in concrete was identified to be ranged between 39 MPa and 54 MPa. Meanwhile, the densities vary between 2000 kg/m3 to 2300 kg/m3.

scholarly journals Influence of Water Pressure on the Mechanical Properties of Concrete after Freeze-Thaw Attack under Dynamic Triaxial Compression State

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Ruijun Wang ◽  
Yan Li ◽  
Yang Li ◽  
Fan Xu ◽  
Xiaotong Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Strain Rate ◽  
Water Pressure ◽  
Mass Loss Rate ◽  
Triaxial Compression ◽  
Ultimate Compressive Strength ◽  
Peak Strain ◽  
Freeze Thaw ◽  
Dynamic Triaxial Compression

This study aims at determining the effect of water pressure on the mechanical properties of concrete subjected to freeze-thaw (F-T) attack under the dynamic triaxial compression state. Two specimens were used: (1) a 100 mm × 100 mm × 400 mm prism for testing the loss of mass and relative dynamic modulus of elasticity (RDME) after F-T cycles and (2) cylinders with a diameter of 100 mm and a height of 200 mm for testing the dynamic mechanical properties of concrete. Strain rates ranged from 10−5·s−1 to 10−3·s−1, and F-T cycles ranged from 0 to 100. Three levels of water pressure (0, 5, and 10 MPa) were applied to concrete. Results showed that as the number of F-T cycles increased, the mass loss rate of the concrete specimen initially decreased and then increased, but the RDME decreased. Under 5 MPa of water pressure and at the same strain rate, the ultimate compressive strength decreased, whereas the peak strain increased with the increase in the number of F-T cycles. This result is contrary to the variation law of ultimate compressive strength and peak strain with the increase in strain rate under the same number of F-T times. With the increase in F-T cycles or water pressure, the strain sensitivity of the dynamic increase factor of ultimate compressive strength and peak strain decreased, respectively. After 100 F-T cycles, the dynamic compressive strength under all water pressure levels tended to increase as the strain rate increased, whereas the peak strain decreased gradually.

Impact of Plasticizers on Technological Properties of Gypsum

2016 ◽  
Vol 865 ◽  
pp. 130-134 ◽  
Author(s):  
Dušan Dolák ◽  
Karel Dvořák
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Mechanical Strength ◽  
Research Work ◽  
High Strength ◽  
Building Industry ◽  
Technological Properties ◽  
Accurate Comparison

Sulphate binders based on gypsum are widely used in building industry. This research work was focused on testing the influence of Melflux plasticizers on the final properties of the gypsum mixture. The aim was to determine the correct concentration of the plasticizer considering workability and improvement of mechanical properties, especially the compressive strength. Different concentrations of plasticizers were tested in mixture of alfa and beta plaster. Each batch was created as paste of normal consistency to create accurate comparison. The results of experiment show significant improvements of mechanical strength of the hardened mixture while maintaining same consistency. This knowledge can be utilized in the design of high-strength sulphate binders.

scholarly journals Degradation of Roller-Compacted Concrete Subjected to Freeze-Thaw Cycles and Immersion in Potassium Acetate Solution

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Wuman Zhang ◽  
Jingsong Zhang ◽  
Shuhang Chen ◽  
Sheng Gong
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Compressive Strength ◽  
Impact Energy ◽  
Impact Test ◽  
Potassium Acetate ◽  
Acetate Solution ◽  
Freeze Thaw ◽  
Roller Compacted Concrete ◽  
The Impact

Two sets of roller-compacted concrete (RCC) samples cured for 28 days were subjected to freeze-thaw (F-T) cycles and immersion in laboratory conditions. F-T cycles in water and water-potassium acetate solution (50% by weight) were carried out and followed by the flexural impact test. The weight loss, the dynamic elastic modulus (Ed), the mechanical properties, and the residual strain of RCC were measured. The impact energy was calculated based on the final number of the impact test. The results show that the effect of F-T cycles in KAc solution on the weight loss and Ed of RCC is slight. Ed, the compressive strength, and the flexural strength of RCC with 250 F-T cycles in KAc solution decrease by 3.8%, 23%, and 36%, respectively. The content (by weight) of K+ at the same depth of RCC specimens increases with the increase of F-T cycles. The impact energy of RCC specimens subjected to 250 F-T cycles in KAc solution decreases by nearly 30%. Microcracks occur and increase with the increase of F-T cycles in KAc solution. The compressive strength of RCC immersed in KAc solution decreases by 18.8% and 32.8% after 6 and 12 months. More attention should be paid to using KAc in practical engineering because both the freeze-thaw cycles and the complete immersion in KAc solution damage the mechanical properties of RCC.

scholarly journals Investigation of the Effect of Addition Nano-papyrus Cane on the Mechanical Properties of Concrete

2021 ◽  
Vol 7 (2) ◽  
pp. 226-235
Author(s):  
Faisal K. Abdulhussein ◽  
Zahraa F. Jawad ◽  
Qais J. Frayah ◽  
ِAwham J. Salman
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Physical Properties ◽  
Construction Material ◽  
Dry Density ◽  
Split Tensile Strength ◽  
Maximum Enhancement ◽  
Concrete Mixtures ◽  
Traditional Construction

This paper investigates the effect of nano-papyrus cane ash as an additive on concretes’ mechanical and physical properties. Three types of concrete mixtures, 1:2:4, 1:1.5:3, and 1:1:2 were prepared for each mixture, nano-papyrus ash was added in five different dosages of 0.75, 1.5, 3, 4.5, and 6% by weight of cement; therefore, eighteen mixes would be studied in this work. Physical properties represented by dry density and slump were also measured for each mix. Moreover, to evaluate the mechanical properties development split tensile strength and compressive strength were obtained at age (7 and 28). Results manifested that the adding of nano ash developed the compressive strength and split tensile strength of concrete and the maximum enhancement recognized in the mixes with a content of 4.5% nano-papyrus in each studied mixture in this work. The slump test results indicated that the workability of concrete increased with adding nano-papyrus ash gradually with increasing nanoparticles' content. As well as, dry density was significant increased with nano-papyrus ratio; greater values were recorded in mixtures with 1.5-4.5% content of nano-papyrus. When comparing the concrete mixes used, it was found that the best results were obtained with 1:1:2 mixtures. This remarkable improvement in concrete properties considers the nano-papyrus is considered a cement economical and useful replacement for traditional construction material. Doi: 10.28991/cej-2021-03091649 Full Text: PDF

scholarly journals Frost resistance of cement-sand and concrete beams during unilateral freezing

2021 ◽  
Vol 2 (1) ◽  
pp. 64-74
Author(s):  
Nepomyach Alexander Nikolaevich ◽  
Vyrovoy Valeriy Nikolaevich ◽  
Chistyakov Artem Aleksaedrovich
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Frost Resistance ◽  
Bending Strength ◽  
Concrete Beams ◽  
Transmission Rate ◽  
Beam Structure ◽  
Freeze Thaw ◽  
Damage Coefficient ◽  
Negative Temperatures

Abstract The work investigates changes in the beam structure under the action of local freezing, which leads to a change of the mechanical properties of the material and, consequently, of the beam structure. Two types of beam samples were used: from cement-sand mortar and from concrete. The work investigates the change in the development of deformations depending on the conditions of freezing of samples. The second accelerated method for assessing frost resistance was chosen according to DSTU B В.2.7-47-96. An accelerated method was chosen for assessing frost resistance at the temperature of -20 ±2 C°. After every five freeze-thaw cycles, the following changes were monitored: mass, water absorption, ultrasound transmission rate, damage coefficient, tensile bending strength, splitting strength, compressive strength, carbonization depth. The results showed that both in concrete and in mortar samples, the compressive strength after freezing was lower by 8% and 15% accordingly. The experimental results obtained confirm the assumptions made that the frost resistance of the material depends on the conditions of exposure of negative temperatures on products and structures and it can be used in a wider range of construction which will push regional development.

scholarly journals Silicate conductive composites with graphite-based fillers

2021 ◽  
Vol 1209 (1) ◽  
pp. 012035
Author(s):  
Š Baránek ◽  
V Černý ◽  
G Yakovlev ◽  
R Drochytka
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Construction Industry ◽  
Machine Building ◽  
Building Industry ◽  
Electrically Conductive ◽  
Conductive Composites ◽  
Flexural Tensile Strength ◽  
Overvoltage Protection

Abstract Electroconductive composites are modern materials that are commonly used in many industries such as construction industry and machine-building industry. For example, these materials can be useful as sensors for monitoring changes in constructions, shielding stray currents from electrification networks, shielding electromagnetic radiation in operating rooms, cathodic protection against moisture or overvoltage protection of buildings. The topic of this post is the research of electrically conductive silicate composites with graphite-based fillers. In this research will be tested composites with different ratio and types of graphite and monitor their electroconductive properties like impedance, and physical-mechanical properties like compressive and tensile strength. The post describes basic properties and interactions of silicate electrically conductive composites with graphite fillers. It was found that by adding 10 % wt. graphite into silicate composites, impedance is reduced by 50% and compressive strength by 40%. The flexural tensile strength depends mainly on the roughness of the particles, where the coarser flaky particles transfer the load better and increase the strength while very fine graphites reduce the flexural tensile strength. Furthermore, it has been found that very finely ground synthetic graphites are most suitable for achieving low impedance of composites.

Frost resistance of roller compacted concrete in airport runway subjected to ethylene glycol solution

2019 ◽  
Vol 66 (1) ◽  
pp. 40-44 ◽  
Author(s):  
Wuman Zhang ◽  
Jingsong Zhang ◽  
Shuhang Chen
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Ethylene Glycol ◽  
Immersion Test ◽  
Bending Test ◽  
Content Type ◽  
Freeze Thaw ◽  
Roller Compacted Concrete ◽  
Practical Engineering ◽  
Airport Runway

Purpose Ethylene glycol (EG) solution is a common deicing fluid of the aircrafts. Roller compacted concrete (RCC) used in the runway and the parking apron will be subjected to freeze-thaw cycles in EG solution. The purpose of this study is to find whether RCC can be damaged by the action of freeze-thaw cycles or long-term immersion in EG solution. Design/methodology/approach Freeze-thaw cycles test and immersion test in EG solution by weight were used to accelerate the degradation of RCC. A compression test and a three-point bending test were carried out in the laboratory to evaluate mechanical properties of RCC. The changes of microstructure were monitored by using scanning electron microscopy and energy-dispersive X-ray analysis. Findings The results show that RCC specimens have little weight change in both freeze-thaw cycles test and immersion test. The dynamic modulus of elasticity, the compressive strength and the flexural strength of RCC with 250 freeze-thaw cycles in EG solution are decreased by 4.2, 15 and 39 per cent, respectively. The compressive strength is decreased by 35 per cent after 12 months of immersion in EG solution. Micro-cracks occur and increase with the increase in freeze-thaw cycles and immersion test. Originality/value The mass ratio of the elements in the crystal is very close to the proportion of elements in CaC2O4 (C:O:Ca = 1:1.26:1.6). More attention should be paid to using EG in practical engineering because both the freeze-thaw cycles and the complete immersion in EG solution damage the mechanical properties of RCC.

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