scholarly journals Performance Evaluation of Cementitious Composites Incorporating Nano Graphite Platelets as Additive Carbon Material

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 290
Author(s):  
Farhan Ahmad ◽  
Arshad Jamal ◽  
Mudassir Iqbal ◽  
Muwaffaq Alqurashi ◽  
Meshal Almoshaogeh ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Water Absorption ◽  
Microstructural Analysis ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Cementitious Composites ◽  
Air Content ◽  
Mechanical Durability ◽  
Huge Impact

Nano graphite platelets (NGPs) belong to the carbon family and have a huge impact on the construction industry. NGPs are used as multi-functional fillers and have the potential to develop reinforcing within cementitious composites. In this paper, NGPs were incorporated in cementitious composites to investigate the effects of NGPs on the fresh, mechanical, durability, and microstructural properties of concrete. Five mixes were prepared with intrusion of NGPs (0%, 0.5%, 1.5%, 3%, and 5% by weight of cement). The properties studied involved workability, air content, hardened density, compressive strength, tensile strength, flexural strength, sorptivity, ultrasonic pulse velocity (UPV), water absorption, and external sulfate attack. The workability and percent air content decrease by 22.5% and 33.8%, respectively, for concrete with 5% NGPs compared to the control mix. The specimens containing 5% of NGPs revealed the hardened density, compressive, tensile, and flexural strength to increase by 11.4%, 38.5%, 31.6%, and 44.34%, respectively, compared to the control mix. The results revealed that the incorporation of 5%NGPs in cementitious composites reduces the sorptivity and water absorption by 32.2% and 73.9%, respectively, whereas, it increases the UPV value by 7.5% compared to the control mix. Furthermore, the incorporation of NGPs provided better resistance against external sulfate attacks. SEM–EDX spectroscopy was carried out to investigate its microstructural analysis.

scholarly journals The effects of adding waste plastic fibers on some properties of roller compacted concrete

2018 ◽  
Vol 162 ◽  
pp. 02008 ◽  
Author(s):  
Adil Abed ◽  
Abdulkader Al-Hadithi ◽  
Ahmed Salih Mohammed
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Water Absorption ◽  
Design Method ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Dry Density ◽  
Waste Plastic ◽  
Roller Compacted Concrete

An attempt to produce of roller compacted concrete (RCC) improved by adding waste plastic fibers (WPFs) resulting from cutting the PET beverage bottles was recorded in this study. The method which is used for production of RCC is an approved design method for ACI committee (5R-207,1980)[1]. WPF was added by volumetric percentages ranging between (0.5 to 2 %) and reference concrete mix was produced for comparison reason. Many tests were conducted on the models produced by rolling compacted concrete like compressive strength, flexural strength, modulus of elasticity, dry density, water absorption and ultrasonic pulse velocity. The analysis of the results showed that the use of plastic waste fibers (1%) had led to improvement in the properties of each of the compressive strength and flexural strength compared with reference concrete. Results also showed that the addition of these, fibers increase water absorption and reduce the speed of Ultrasonic pulse velocity.

scholarly journals Attempts to Improve the Subsurface Properties of Horizontally-Formed Cementitious Composites Using Tin(II) Fluoride Nanoparticles

Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 83 ◽  
Author(s):  
Kamil Krzywiński ◽  
Łukasz Sadowski ◽  
Jacek Szymanowski ◽  
Andrzej Żak ◽  
Magdalena Piechówka-Mielnik
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Abrasion Resistance ◽  
Mechanical Performance ◽  
Reference Sample ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Cementitious Composites ◽  
Fluoride Nanoparticles

This article presents studies that were performed in order to improve the subsurface properties of horizontally-formed cementitious composites using tin(II) fluoride nanoparticles. The main aim of the study was to solve the problem of the decrease in subsurface properties caused by mortar bleeding and the segregation of the aggregate along the height of the overlay. The article also aims to highlight the patch grabbing difficulties that occur during the process of forming horizontally-formed cementitious composites. Four specimens were analyzed: one reference sample and three samples modified with the addition of 0.5, 1.0, and 1.5% of tin(II) fluoride nanoparticles in relation to the cement mass. To analyze the mechanical properties of the specimens, non-destructive (ultrasonic pulse velocity) and destructive tests (flexural tensile strength, compressive strength, abrasion resistance, pull-off strength) were performed. It was indicated that due to the addition of the tin(II) fluoride, it was possible to enhance the subsurface tensile strength and abrasion resistance of the tested cementitious composites. To confirm the obtained macroscopic results, the porosity of the subsurface was measured using SEM. It was also shown that the addition of the tin(II) fluoride nanoparticles did not reduce its flexural and compressive strength. The results show that horizontally-formed cementitious composites with the addition of 1.0% of tin(II) fluoride nanoparticles in relation to the cement mass obtained the most effective mechanical performance, especially with regard to subsurface properties.

scholarly journals A Study on Tannery Sludge as a Raw Material for Cement Mortar

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1562 ◽  
Author(s):  
Jurgita Malaiškienė ◽  
Olga Kizinievič ◽  
Viktor Kizinievič
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Cement Mortar ◽  
Ultrasonic Pulse Velocity ◽  
Xrd Analysis ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Raw Material ◽  
Tannery Sludge ◽  
Limit Values

The paper analyses the properties (chemical and mineral composition, microstructure, density, etc.) of recycled tannery sludge (TS) and the possibilities for using it in cement mortar mixture. Mortar specimens containing 3–12% of tannery sludge by weight of cement and 3–9% of tannery sludge by weight of sand were tested. Flowability, density, ultrasonic pulse velocity (UPV), flexural and compressive strength, water absorption and sorptivity of the mortar were analysed. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis of tannery sludge and mortar are presented. The tests revealed that replacement of 6% of cement with tannery sludge in the mix increased flexural and compressive strength and UPV values, whereas water absorption decreased. SEM and XRD analysis revealed that specimens with tannery sludge contained lower amounts of ettringite and higher amounts of portlandite; the obtained structure was denser and contained more calcium hydrosilicates (C-S-H). Chromium leaching values in cement mortars were found not to exceed the limit values set forth in Directive 2003/33/EC.

scholarly journals Non Destructive Studies on Engineered Cementitious Composites using Microsilica & Polypropylene Fibre

2019 ◽  
Vol 8 (2S5) ◽  
pp. 18-21
Keyword(s):  
Compressive Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Mineral Admixture ◽  
Cementitious Composites ◽  
Engineered Cementitious Composites ◽  
Polypropylene Fibres ◽  
Curing Regimes ◽  
Non Destructive

This study focuses on assessing the durability property of engineered cementitious composites using Ultrasonic pulse velocity method (direct and semi direct) to compute the compressive strength. Even the effect of mineral admixture on the mortar properties for different curing regimes shall be determined using this method. Mortar specimens containing microsilica in different percentages ranging from 5% to 25%, replacing portland cement by weight and adding polypropylene fibres ranging from 0.5% to 2% are chosen for evaluation. 20% of microsilica and 2% of polypropylene fibres induced to increase the range of UPV from 3463 m/s to 3505 m/s for 7 and 28 day curing regimes and also the compressive strength significantly improved for the above constituent. However there was a marginal decrease in the compressive strength and UPV outcomes when cement is replaced by microsilica greater than 20%. A relationship had been framed between ultrasound pulse velocity and compressive strength.

scholarly journals Enhancing Sustainable Concrete Properties by Green Vegetable Substance

2018 ◽  
Vol 7 (4.37) ◽  
pp. 219
Author(s):  
Zainab Hasan Abdulabbas ◽  
Marwa Asad Salih ◽  
Ali Talib Jasim
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Soft Drink ◽  
Gum Arabic ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Waste Materials ◽  
Concrete Properties ◽  
Concrete Production

From several points of view, disposal of waste materials in an environment is respected to be a significant problem because of its very low biodegradability and existence in huge quantities. Waste of plastic and metal bottles caps, cans of juices and soft drink, and tires rubber being among the most pronounced. This study was conducted to evaluate the efficiency of reusing these waste materials in concrete production and solve the segregation problem. As segregation increases in concrete involving these waste materials due to lighter weight of them relative to nature aggregate, therefore, attention was intensive on using natural product (Gum Arabic) that is an environmentally friendly chemical material for improving concrete properties. The conducted tests include; compressive strength, flexural strength, splitting tensile strength, density, water absorption, and ultrasonic pulse velocity. The results showed that replacing the volume of coarse aggregate by 25% compacted bottles caps and pull-tab of cans, 20% the plastic bottle caps, and 25% tires rubber shreds used decreased the mechanical properties of concrete to some extent less than reference mix and they were enhanced by employing Gum Arabic. In addition, the employment of Gum Arabic as liquid in concrete mixes developed the mechanical properties of concrete, reduced segregation, however raised the water absorption percent and declined the density of concrete.  

scholarly journals Effects of Incorporation of Marble Powder Obtained by Recycling Waste Sludge and Limestone Powder on Rheology, Compressive Strength, and Durability of Self-Compacting Concrete

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Rayed Alyousef ◽  
Omrane Benjeddou ◽  
Chokri Soussi ◽  
Mohamed Amine Khadimallah ◽  
Abdeliazim Mustafa Mohamed
Keyword(s):  
Compressive Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Limestone Powder ◽  
Self Compacting Concrete ◽  
Limestone Filler ◽  
Air Content ◽  
Marble Powder ◽  
Strength And Durability

Marble has been commonly used as a building material since ancient times. The disposal of waste materials from the marble industry, consisting of sludge that is composed of powder mixed with water, is one of the current worldwide environmental problems. This experimental study aims to valorize marble powder, which is achieved by grinding the sludge as filler added to the cementitious matrix of self-compacting concrete (SCC). The main purpose of this work is to evaluate the marble filler effects on the rheology in the fresh state and on the hardened properties of SCCs compared to those of limestone filler. To this end, two SCCs, SCCM and SCCL, manufactured using marble powder and limestone filler, respectively, were prepared and tested. The fresh properties of the two SCCs’ mixtures were determined by slump flow, L-box, V-funnel, sieve stability, bulk density, and air content. Tests on hardened SCCs included compressive strength, homogeneity, and quality in terms of ultrasonic pulse velocity and durability against carbonation and water penetration. In addition, scanning electron microscope (SEM) and X-ray diffraction (XRD) were used to analyze the specimens.

scholarly journals Characteristics of Preplaced Aggregate Concrete Fabricated with Alkali-Activated Slag/Fly Ash Cements

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 591
Author(s):  
Salman Siddique ◽  
Hyeju Kim ◽  
Hyemin Son ◽  
Jeong Gook Jang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Absorption ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Cement Grout ◽  
Aggregate Concrete ◽  
Alkali Activated ◽  
Alkali Activated Cement

This study assesses the characteristics of preplaced aggregate concrete prepared with alkali-activated cement grout as an adhesive binder. Various binary blends of slag and fly ash without fine aggregate as a filler material were considered along with different solution-to-solid ratios. The properties of fresh and hardened grout along with the properties of hardened preplaced concrete were investigated, as were the compressive strength, ultrasonic pulse velocity, density, water absorption and total voids of the preplaced concrete. The results indicated that alkali-activated cement grout has better flowability characteristics and compressive strength than conventional cement grout. As a result, the mechanical performance of the preplaced aggregate concrete was significantly improved. The results pertaining to the water absorption and porosity revealed that the alkali-activated preplaced aggregate concrete is more resistant to water permeation. The filling capacity based on the ultrasonic pulse velocity value is discussed to comment on the wrapping ability of alkali-activated cement grout.

scholarly journals Mechanical Properties of Na2CO3-Activated High-Volume GGBFS Cement Paste

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Taewan Kim ◽  
Yubin Jun
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
High Volume ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Strength Development ◽  
X Ray Diffraction ◽  
Granulated Blast Furnace Slag ◽  
Dry Shrinkage

The use of Na2CO3 to improve the mechanical properties of high-volume slag cement (HVSC) is experimentally investigated in this study. Ordinary Portland cement (OPC) was replaced with 50, 60, 70, 80, and 90% ground-granulated blast-furnace slag (GGBFS) by weight. Na2CO3 was added at 0, 1, 2, 3, 4, and 5 wt.% of HVSC (OPC + GGBFS). The compressive strength, water absorption, ultrasonic pulse velocity, dry shrinkage, and X-ray diffraction spectra of the Na2CO3-activated HVSC pastes were analyzed. The results indicate that Na2CO3 was effective for improving the strength of HVSC samples at both early and later ages. There was a trend of increasing HVSC sample strength with increasing Na2CO3 content. The 5% Na2CO3-activated HVSC (50% OPC + 50% GGBFS) paste had the best combination of early to later-age strength development and exhibited the highest UPV and the lowest water absorption among the Na2CO3-activated HVSC samples at later age.

scholarly journals Analysis of damage failure in uniaxial compressive of cemented paste backfill by ultrasonic pulse velocity test

2021 ◽  
Vol 37 (2) ◽  
Author(s):  
B. Wang ◽  
L. Li ◽  
Y. Yu ◽  
B. Huo ◽  
J. Liu
Keyword(s):  
Mass Fraction ◽  
Damage Mechanics ◽  
Microstructural Analysis ◽  
Ultrasonic Pulse Velocity ◽  
Cementitious Materials ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Experimental Results ◽  
Cemented Paste Backfill ◽  
Paste Backfill

Cemented paste backfill (CPB) is prepared by mixing cementitious materials, tailings and water. Uniaxial compressive strength (UCS) is one of the most commonly used indicators for evaluating the mechanical performance of CPB. Ultrasonic pulse velocity (UPV) testing which is a non-destructive measurement, can also be applied to determine the mechanical properties of cement-based materials such as CPB. In order to study the failure mechanism of CPB,144 CPB samples prepared at different mass fraction and cement-tailing ratios were subjected to the UCS and UPV tests at 7,14 and 28 days of curing age. The effect of cement-tailing ratio and mass fraction on the UCS and UPV of CPB samples were obtained, the UCS values were correlated with the corresponding UPV data. Microstructural analysis was also performed on CPB samples to understand the effect of microstructure on the UCS data. The results show that the UCS and UPV values of CPB increased with cement-tailing ratio, mass fraction and curing time. Based on the experimental results, the damage constitutive equations and the damage evolution equations of different backfills were proposed on the basis of damage mechanics. Moreover, comparative analysis of constitutive model and experimental results were made to verify the reliability of the damage model. The results acquired by this paper provide a scientific basis for the rational strength design of backfill mine.

scholarly journals Behaviour of Incorporation of Bacteria in Concrete

2021 ◽  
Vol 889 (1) ◽  
pp. 012022
Author(s):  
Aditya Kumar Tiwary
Keyword(s):  
Flexural Strength ◽  
Healing Process ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Conventional Concrete ◽  
Concrete Crack ◽  
Micro Cracks ◽  
Enterobacter Species ◽  
Compressive Strength Of Concrete

Abstract The life of the healing in concrete is many years old and when the study was done on this, outcomes were coinciding with the auto-genus healing process which was capable to heal the micro cracks inside cementitious based materials and hereafter research led to the study of autonomous healing. In the autonomous healing process, the main aim was to fill the cracks and heal the fracture at the macro level. This was possible with the help of bacteria that were embedded in the cementitious based material with different technologies and methods. In this paper, Enterobacter species and Cohnii bacteria were incorporated into concrete. The behaviour of bacterial concrete was investigated in terms of compressive, tensile, flexural strength and ultrasonic pulse velocity. It observed that the compressive strength of concrete was increased by 11.5%, flexural strength increased by 11.9%, tensile strength increased by 12.8% with the replacement of Cohnii bacteria as compare to conventional concrete. These bacteria have been proved a positive approach to the healing process in cementitious based material. Also, the important criterion has been studied which is essential when dealing with the autonomous healing process. Both the bacteria generate the calcite that helps to fill the concrete crack and voids if water come in to contact.

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