Some Properties of Cement Mortar Incorporating Micro and Nano-Metakaolin Materials

2021 ◽  
Vol 1021 ◽  
pp. 231-240
Author(s):  
Manolia Abed Al-Wahab Ali ◽  
Mohammed Jawad Kadhim ◽  
Ibtesam F. Nasser
Keyword(s):  
Flexural Strength ◽  
Greenhouse Gas Emission ◽  
Cement Mortar ◽  
Physical And Mechanical Properties ◽  
Pozzolanic Reaction ◽  
Mineral Admixture ◽  
Concrete Technology ◽  
Binder Ratio ◽  
Substitution Ratio ◽  
High Production

There are many reasons neededfor continuous evolution in concrete technology; one of them concern on the greenhouse gas emission and depletion of natural resource as a results of high production of Portland cement. Many solutions are used to solve these problems; one of them is using cement replacement materials in concrete like metakaolin (in micro or Nano scale) which offered positive effect on the properties of cement concrete. Therefore, the main aim of this study is to evaluate and compare the effects of metakaolin (MK) and Nano-metakaolin (NMK) on some physical and mechanical properties of cement mortar. For this purpose, mortar mixes are prepared by substituting cement (by weight) with (10%) metakaolin or (1, 3, 5, and 7%) Nano - metakaolin. The amount of binder for mortar mixtures is 700 kg/m with a constant water / binder ratio of 0.33. Workability, apparent density, water absorption, compressive strength, and flexural strength of all mortar mixes are determined and compared with reference mix without any mineral admixture (0% MK or NMK). The results indicated that the performance of mortar mixes can be enhanced by metakaoline replacement. Furthermore, Nano-metakaolin has significantly positive impacts on the properties of mortar mixes which have found to be improved with increasing the Nano-metakaolin replacement, due to better pore refinement, micro filling action, and higher pozzolanic reaction. The optimum Nano-metakaolin substitution ratio (7%) causes increase in compressive and flexural strength reach to (82.6% and 59.5%), respectively compared with the reference mix, at age of 28 days.

scholarly journals IMPROVING THE VOLUMETRIC STABILITY OF WHITE CEMENT BY USING SOME ADDITIVES

2021 ◽  
Vol 25 (Special) ◽  
pp. 2-65-2-71
Author(s):  
Marwa A. Anber ◽  
◽  
Mohammed A. Abdulrehman ◽  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Polyvinyl Alcohol ◽  
Cement Mortar ◽  
Physical And Mechanical Properties ◽  
Drying Shrinkage ◽  
Limestone Powder ◽  
Mixing Ratio ◽  
White Cement ◽  
Dry Shrinkage

Abstract: This study looked at the effects of three types of additives: limestone powder, Arabian gum AG, and polyvinyl alcohol (PVA), on White Cement Mortar's Physical and Mechanical Properties the mixing ratio for dry shrinkage was 1:2. (Cement: sand) while for other tests, it was 1:2.75 (cement: sand). The limestone powder proportions are (5%, 10%, and 15%) by weight of white cement, while the AG ratios are (0.2, 0.5, and 0.8) % by weight of white cement, the polyvinyl alcohol ratios are (2%, 4%, and 6%). This study was focused at the compressive and flexural strength of the modified mortar, as well as water absorption and drying shrinkage. According to the findings, utilizing of limestone powder as additive in white cement mortar is not advised. Since it had the negative affect on dry shrinkage of the mortar. Furthermore, polymer additives such as AG and PVA significantly increase the reduction of ability of forming crack in white cement mortar. Furthermore, the optimal additive percentages of AG and PVA are 0.5 percent and 6%, respectively.

scholarly journals Performance of Carbon Fiber Filament Reinforcing Cement Mortar

2021 ◽  
Vol 7 (10) ◽  
pp. 1693-1701
Author(s):  
Ahmed Hamed El-Sayed Salama ◽  
Walid Fouad Edris
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Cement Mortar ◽  
Physical And Mechanical Properties ◽  
Experimental Program ◽  
Flow Table ◽  
Compressive And Flexural Strengths ◽  
Measured Density

This paper aims to study the effect of Carbon Fiber Filament (CFF) with different ratios and lengths on the physical and mechanical properties of cement mortar. An experimental program included 3 cm fixed length of CFF with 0, 0.25, 0.5, 0.75, and 1% different ratios by weight of cement addition were used in cement mortar cubes. Another experimental program of 0.5% CFF ratio with 1, 2, 3, 4, and 5 cm different lengths by weight of cement addition was used in cement mortar prisms. The physical and mechanical properties of cement mortar containing CFF were experimentally investigated at 7 and 28 days of curing. Workability, by means of flow table test, were measured. Density is conducted for cubes and prisms at the age of 28 days. At ages of 7 and 28 days, compressive and flexural strengths were studied. The study showed a reduction in workability with the increase of CFF ratios and lengths by 0.0 to 2.7% and by 0.9 to 5.4% respectively. Moreover, an improvement in density, compressive, and flexural strengths was observed. At ages of 7 and 28 days, the results showed that compressive strength increased by 33 and 31% respectively at 0.5% of CFF ratio while the flexural strength increased by 125 and 327% respectively with CFF length of 5 cm. Doi: 10.28991/cej-2021-03091753 Full Text: PDF

scholarly journals The Effect of Partial Replacement of Polymethyl Methacrylate(PMMA) on the Compressive and Flexural Strength of Ordinary Cement Mortar

2020 ◽  
Vol 5 (4) ◽  
pp. 443-447
Author(s):  
Mustafa Kadhim Rustum ◽  
Khalid M. Eweed
Keyword(s):  
Flexural Strength ◽  
Polymethyl Methacrylate ◽  
Cement Mortar ◽  
Microstructural Analysis ◽  
Sem Analysis ◽  
Partial Replacement ◽  
Early Age ◽  
Homogeneous Microstructure ◽  
Binder Ratio ◽  
The Impact

 In this paper studied the impact of the partial replacement of the cement by self-cure polymer (polymethyl methacrylate PMMA) in different ratios on the compressive strength, flexural strength and microstructural analysis, five ratios of cement replacement (1%, 3%, 5%, 7%, and 9%) by PMMA, these tests have been performed after curing at an early age (7days) and standard age (28days). The preparation of the mortar has been performed with the use of 1:2 cement to the sand ratio by weight, with (0.5) water to binder ratio and polymer to self-cure monomer (methyl methacrylate MMA) ratio 2:1. Results have shown that the flexural and the compressive strengths of mortars have been increased with increasing the ratio of the replacement (1%, 3%, 5%) and then decreased at replacement ratio (7% and 9%). The best results of the new cement mortar were reached at the partial replacement of cement with 5% of PMMA were recorded enhancement of compressive strength15.8% at an early age and 24.4% for standard age and enhancement of flexural strength 16.8% at an early age and 19.4% for standard age, from scanning electron microscopy SEM analysis observed the PMMA filling the pores and form more homogeneous microstructure in G32 as compared with the microstructure of G1.

Lightweight Fibre Reinforced Concrete

2016 ◽  
Vol 249 ◽  
pp. 28-32
Author(s):  
Michala Hubertova ◽  
Rudolf Hela
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Lightweight Concrete ◽  
Physical And Mechanical Properties ◽  
Hardened Concrete ◽  
Strain Diagram ◽  
Fibre Reinforcement ◽  
Fibre Reinforced Concrete ◽  
Concrete Technology ◽  
Aggregate Concrete

The use of fibre reinforcement in normalweight concrete technology is commonly used in practice. In the area of lightweight concrete, for example with use of expanded clay aggregate, there is not widely used this type of technology. The paper describes the experimental verification of various doses of steel fibres in two types of bulk and compressive class of lightweight expanded clay aggregate concrete and its influence on the physical and mechanical properties of hardened concrete – compressive and flexural strength, stress-strain diagram.

Reutilization of RFA of Construction Waste in Cement Mortar

2013 ◽  
Vol 468 ◽  
pp. 57-60
Author(s):  
Fu Xing Wang ◽  
Guo Zhong Li ◽  
Juan Chen
Keyword(s):  
Grain Size ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Cement Mortar ◽  
Mineral Admixture ◽  
Fine Aggregate ◽  
Hydration Products ◽  
Construction Waste ◽  
Recycled Fine Aggregate ◽  
Micro Morphology

The effect of some factors(dosage and grain size of recycled fine aggregate of construction waste, content of mineral admixture) on the properties of cement mortar was studied. The results indicated that when recycled fine aggregate particles gradation was areaⅡ, replacement percentage (sand) was 60%,dosage of mineral admixture was 36%, compared with blank sample, the 28d flexural strength and the compressive strength of cement mortar samples were increased by 30.7% and 37.2%, respectively. Micro-morphology of section on cement mortar was observed by SEM. Identifying the hydration products through XRD was carried out.

The Mechanical Properties of Lightweight Concrete under Different Factors

2014 ◽  
Vol 665 ◽  
pp. 203-207
Author(s):  
Xi Liu ◽  
Bei Bei Lv ◽  
Tao Wu
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Lightweight Concrete ◽  
Physical And Mechanical Properties ◽  
Lightweight Aggregate ◽  
Mineral Admixture ◽  
Lightweight Aggregate Concrete ◽  
Mixture Ratio ◽  
Absolute Volume ◽  
Binder Ratio

By choosing domestic ceramsite as lightweight aggregate, mixing with active mineral admixture (fly ash) and the water reducing agent, and adopting the method of absolute volume to design the three ceramsite concretemixture ratio, 27 groups, 243 lightweight aggregate ceramsite concrete test cubes of 100mm×100mm×100mm are obtained for compressive strength test, and the physical and mechanical properties of the aggregate are studied. At the same time, through the systematic test, the influences of the aggregate strength, water-binder ratio, fly-ash content, etc on ceramsite concrete are studied. Finally the best mixture ratio scheme for ceramsite concrete is gained, providing theoretical basis for the application of lightweight aggregate concrete.

scholarly journals Preparation of Electric- and Magnetic-Activated Water and Its Influence on the Workability and Mechanical Properties of Cement Mortar

2021 ◽  
Vol 13 (8) ◽  
pp. 4546
Author(s):  
Kaiyue Zhao ◽  
Peng Zhang ◽  
Bing Wang ◽  
Yupeng Tian ◽  
Shanbin Xue ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Cement Paste ◽  
Cement Mortar ◽  
Environmental Issues ◽  
Chemical Admixtures ◽  
Untreated Water ◽  
Alternating Voltage

Cement-based materials prepared with activated water induced by a magnetic field or electric field represent a possible solution to environmental issues caused by the worldwide utilization of chemical admixtures. In this contribution, electric- and magnetic-activated water have been produced. The workability and mechanical properties of cement mortar prepared with this activated water have been investigated. The results indicate that the pH and absorbance (Abs) values of the water varied as the electric and magnetic field changed, and their values increased significantly, exhibiting improved activity compared with that of the untreated water. In addition, activated water still retains activity within 30 min of the resting time. The fluidity of the cement paste prepared with electric-activated water was significantly larger than that of the untreated paste. However, the level of improvement differed with the worst performance resulting from cement paste prepared with alternating voltage activated water. In terms of mechanical properties, both compressive strength and flexural strength obtained its maximum values at 280 mT with two processing cycles. The compressive strength increased 26% as the curing time increased from 7 days to 28 days and flexural strength increased by 31%. In addition, through the introduction of magnetic-activated water into cement mortar, the mechanical strength can be maintained without losing its workability when the amount of cement is reduced.

scholarly journals Properties of Calcium Sulfoaluminate Cement Mortar Modified by Hydroxyethyl Methyl Celluloses with Different Degrees of Substitution

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2136
Author(s):  
Shaokang Zhang ◽  
Ru Wang ◽  
Linglin Xu ◽  
Andreas Hecker ◽  
Horst-Michael Ludwig ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Bond Strength ◽  
Cement Mortar ◽  
Retention Rate ◽  
Methyl Cellulose ◽  
Tensile Bond Strength ◽  
Calcium Sulfoaluminate Cement ◽  
Calcium Sulfoaluminate ◽  
Cement Mortars

This paper studies the influence of hydroxyethyl methyl cellulose (HEMC) on the properties of calcium sulfoaluminate (CSA) cement mortar. In order to explore the applicability of different HEMCs in CSA cement mortars, HEMCs with higher and lower molar substitution (MS)/degree of substitution (DS) and polyacrylamide (PAAm) modification were used. At the same time, two kinds of CSA cements with different contents of ye’elimite were selected. Properties of cement mortar in fresh and hardened states were investigated, including the fluidity, consistency and water-retention rate of fresh mortar and the compressive strength, flexural strength, tensile bond strength and dry shrinkage rate of hardened mortar. The porosity and pore size distribution were also analyzed by mercury intrusion porosimetry (MIP). Results show that HEMCs improve the fresh state properties and tensile bond strength of both types of CSA cement mortars. However, the compressive strength of CSA cement mortars is greatly decreased by the addition of HEMCs, and the flexural strength is decreased slightly. The MIP measurement shows that HEMCs increase the amount of micron-level pores and the porosity. The HEMCs with different MS/DS have different effects on the improvement of tensile bond strength in different CSA cement mortars. PAAm modification can improve the tensile bond strength of HEMC-modified CSA cement mortar.

scholarly journals Effect of Hydrogen Nanobubbles on the Mechanical Strength and Watertightness of Cement Mixtures

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1823
Author(s):  
Won-Kyung Kim ◽  
Young-Ho Kim ◽  
Gigwon Hong ◽  
Jong-Min Kim ◽  
Jung-Geun Han ◽  
...  
Keyword(s):  
Mercury Intrusion Porosimetry ◽  
Cement Mortar ◽  
Stable State ◽  
Pozzolanic Reaction ◽  
Hydration Reaction ◽  
High Concentration ◽  
Mercury Intrusion ◽  
Electron Microscope Analysis ◽  
Mixing Water ◽  
Cement Mixtures

This study analyzed the effects of applying highly concentrated hydrogen nanobubble water (HNBW) on the workability, durability, watertightness, and microstructure of cement mixtures. The number of hydrogen nanobubbles was concentrated twofold to a more stable state using osmosis. The compressive strength of the cement mortar for each curing day was improved by about 3.7–15.79%, compared to the specimen that used general water, when two concentrations of HNBW were used as the mixing water. The results of mercury intrusion porosimetry and a scanning electron microscope analysis of the cement paste showed that the pore volume of the specimen decreased by about 4.38–10.26%, thereby improving the watertightness when high-concentration HNBW was used. The improvement in strength and watertightness is a result of the reduction of the microbubbles’ particle size, and the increase in the zeta potential and surface tension, which activated the hydration reaction of the cement and accelerated the pozzolanic reaction.

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