Evaluation of the Mechanical Properties of Self-Compacting Lightweight Concrete Exposed to Wet and Dry Cycles in Saltwater

2016 ◽  
Vol 711 ◽  
pp. 218-223
Author(s):  
Sherif Yehia ◽  
Sharef Farrag
Keyword(s):  
Mechanical Properties ◽  
Phase Ii ◽  
Lightweight Concrete ◽  
Experimental Program ◽  
Strength Development ◽  
Sem Images ◽  
Paper Properties ◽  
Two Phases ◽  
Wet And Dry Cycles ◽  
Exposure Conditions

In this paper, properties of a self-compacting lightweight concrete that has been exposed to cycles of wetting in saltwater and drying in air are investigated. Such exposure conditions are common in marine structures with pronounced sea level variation. The experimental program consisted of two phases; Phase I included monitoring of the strength development for 28 days, while in Phase II samples were exposed to wet/dry cycles for 12 months. In addition, control samples were kept in room temperature without exposure for comparison. Compressive and flexural strength, modulus of elasticity and Rapid Chloride Penetration (RCP) were included in the investigation. In addition, Scanning Electron Microscopy (SEM) was conducted to examine the microstructure of the samples in phase II. Results from the experimental program indicate that there was a negligible effect on the mechanical properties or RCP due to the exposure conditions. However, a close inspection of the SEM images showed salt deposits and micro cracking in the cement paste. This may affect the long-term durability and can lead to deterioration of the concrete structure, hence reducing the structure’s service life.

scholarly journals Effects of In-Situ Filler Loading vs. Conventional Filler and the Use of Retention-Related Additives on Properties of Paper

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5066
Author(s):  
Maria Emiliana Fortună ◽  
Andrei Lobiuc ◽  
Lucian-Mihai Cosovanu ◽  
Maria Harja
Keyword(s):  
Mechanical Properties ◽  
Calcium Carbonate ◽  
Filler Loading ◽  
Carbonate Content ◽  
Sem Images ◽  
Paper Properties ◽  
Calcium Carbonate Content ◽  
Optical And Mechanical Properties ◽  
Filler Retention

In the present paper, aspects concerning the obtained and characterization of additive systems used for maximizing filler retention, and the effects on paper properties, were investigated. The effects of retention additives over properties of paper, containing fibers from in-situ loading (IS-CCP), were analyzed against the effects of additives over properties of paper containing fibers from conventional loading, obtained by the addition of calcium carbonate in precipitated form (CCP). The physico-mechanical properties were analyzed by various analyses and investigations: calcium carbonate content, X-ray diffraction, scanning electron microscopy (SEM) images, optical and mechanical properties, in order to develop the best systems of retention additives for obtaining higher retention loads for making paper with high content of nano-filler material. The obtained results reveal that at the same level of calcium carbonate content, all paper samples with in-situ loading had higher the optical and mechanical properties than the paper obtained by conventional loading in all cases the additives studied. For all studied properties, nanoparticles had a positively influence over paper properties.

Study of the Strength Development of the Cement Matrix for Textile Reinforced Concrete

2014 ◽  
Vol 1054 ◽  
pp. 99-103 ◽  
Author(s):  
Filip Vogel ◽  
Ondřej Holčapek ◽  
Petr Konvalinka
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Experimental Program ◽  
Cement Matrix ◽  
Strength Development ◽  
Textile Reinforced Concrete ◽  
Similar Composition ◽  
Strength In Bending

This article deals with cement matrix for textile reinforced concrete. The main topic of this article is study of the development of the mechanical properties of the cement matrix. It was studied cube compressive strength and tensile strength in bending. The cement matrix has a similar composition as high performance concrete. Commonly used concrete was made to compare with the cement matrix. The cubes and prisms were made for the experimental program. The mechanical properties were studied at the age 12, 15, 18 and 21 hours and 1, 2, 3, 7, 14, 21 and 28 days.

scholarly journals Enhanced Interfacial and Mechanical Properties of PBX Composites via Surface Modification on Energetic Crystals

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1308 ◽  
Author(s):  
Chengcheng Zeng ◽  
Zhijian Yang ◽  
Jianhu Zhang ◽  
Yubin Li ◽  
Congmei Lin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Interfacial Interaction ◽  
Polar Component ◽  
Sem Images ◽  
Polymer Binders ◽  
A Value ◽  
Polymer Bonded Explosives ◽  
Two Phases ◽  
Energetic Composites

The mechanical properties of composites are highly dependent on the interfacial interaction. In the present work, inspired by marine mussel, the adhesion between energetic crystals of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) and polymer binders was improved. Three types of linear polymeric agents of glycidyl azide polymer (GAP), polyethylene glycol (PEG), and polytetramethylene ether glycol (PTMEG) were grafted onto TATB particles bridged through polydopamine (PDA) films. SEM images showed that 5% grafting contents could evidently form roughness shells on the surface. With a reinforcement at the interface produced by grafting shells, the mechanical properties of polymer-bonded explosives (PBXs) exhibited outstanding mechanical performance, especially for the PTMEG-grafting sample. Examined by the contact-angle test, the PTMEG-grafting sample possessed a value of polar component similar to that of fluoropolymer, leading to an excellent wettability of the two phases. Additionally, different contents of PTMEG were grafted to reveal that the mechanical properties could be improved even with content as little as 0.5 wt.% PTMEG. These results might highlight a correlation between interfacial interaction and macroscopic properties for mechanically energetic composites, while providing a versatile route of grafting on highly loaded composites.

scholarly journals Mechanical Properties of Cement-Treated Soil Mixed with Cellulose Nanofibre

2021 ◽  
Vol 11 (14) ◽  
pp. 6425
Author(s):  
Hidenori Takahashi ◽  
Shinya Omori ◽  
Hideyuki Asada ◽  
Hirofumi Fukawa ◽  
Yusuke Gotoh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Geotechnical Engineering ◽  
Strength Development ◽  
Soft Ground ◽  
Wood Cellulose ◽  
Treated Soil ◽  
Made In ◽  
Cement Treatment

Cellulose nanofibre (CNF), a material composed of ultrafine fibres of wood cellulose fibrillated to nano-order level, is expected to be widely used because of its excellent properties. However, in the field of geotechnical engineering, almost no progress has been made in the development of techniques for using CNFs. The authors have focused on the use of CNF as an additive in cement treatment for soft ground, where cement is added to solidify the ground, because CNF can reduce the problems associated with cement-treated soil. This paper presents the results of a study on the method of mixing CNF, the strength and its variation obtained by adding CNF, and the change in permeability. CNF had the effect of mixing the cement evenly and reducing the variation in the strength of the treated soil. The CNF mixture increased the strength at the initial age but reduced the strength development in the long term. The addition of CNF also increased the flexural strength, although it hardly changed the permeability.

scholarly journals Influence of Alkali Treatment on the Microstructure and Mechanical Properties of Coir and Abaca Fibers

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2636
Author(s):  
Petr Valášek ◽  
Miroslav Müller ◽  
Vladimír Šleger ◽  
Viktor Kolář ◽  
Monika Hromasová ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Alkali Treatment ◽  
Fiber Surface ◽  
Cellulose Fibers ◽  
Sem Analysis ◽  
Experimental Program ◽  
Time Interval ◽  
The European Union ◽  
Vegetable Fibers

Composite materials with natural fillers have been increasingly used as an alternative to synthetically produced materials. This trend is visible from a representation of polymeric composites with natural cellulose fibers in the automotive industry of the European Union. This trend is entirely logical, owing to a preference for renewable resources. The experimental program itself follows pronounced hypotheses and focuses on a description of the mechanical properties of untreated and alkali-treated natural vegetable fibers, coconut and abaca fibers. These fibers have great potential for use in composite materials. The results and discussion sections contribute to an introduction of an individual methodology for mechanical property assessment of cellulose fibers, and allows for a clear definition of an optimal process of alkalization dependent on the content of hemicellulose and lignin in vegetable fibers. The aim of this research was to investigate the influence of alkali treatment on the surface microstructure and tensile properties of coir and abaca fibers. These fibers were immersed into a 5% solution of NaOH at laboratory temperature for a time interval of 30 min, 1 h, 2 h, 3 h, 6 h, 12 h, 24 h, and 48 h, rinsed and dried. The fiber surface microstructures before and after the alkali treatment were evaluated by SEM (scanning electron microscopy). SEM analysis showed that the alkali treatment in the NaOH solution led to a gradual connective material removal from the fiber surface. The effect of the alkali is evident from the visible changes on the surface of the fibers.

scholarly journals Mineralogical Composition and Physical–Mechanical Properties of Dasht-E-Taatrang Zar Sand Deposits (Afghanistan)

2020 ◽  
Vol 5 (1) ◽  
pp. 2
Author(s):  
Hemayatullah Ahmadi ◽  
Atal Yousufi ◽  
Amir Mohammad Mosazai
Keyword(s):  
Mechanical Properties ◽  
Construction Material ◽  
Mineralogical Composition ◽  
Xrd Analysis ◽  
Sample Collection ◽  
Extensive Field ◽  
Chemical And Mineralogical Composition ◽  
New City ◽  
Two Phases ◽  
Field Works

Sand is a common construction material used for various purposes, e.g., concrete, mortar, render, screed, and asphalt. The usage depends on its fineness, and its fineness is controlled by its mineralogical composition and physical-mechanical properties. This research aims to determine the chemical and mineralogical composition and the physical-mechanical properties of the Dasht-e-Taatrang Zar sand deposits within the Qarabagh and Bagram districts of Kabul and Parwan provinces in Afghanistan. To achieve the objectives of this research, a review of the existing literature has been combined with new extensive field works for macroscopic studies and sample collection, and laboratory analyses. In total, 23 samples during two phases of field works were collected and subjected to lab works for XRF, Schlich, and XRD analysis to determine the chemical and mineralogical composition; moreover, sieve and Atterberg analysis, specific gravity, soundness, and alkali-silica reaction tests were performed for characterization of the physical-mechanical properties of the studied samples. The results of the tests show that the Taatrang Zar sand deposits are considered as a suitable construction material, and due to their simple accessibility, the deposits have high potential as a construction material supplier for the Kabul new city project (Dehsabz) in Kabul and adjacent Parwan and Kapisa provinces.

scholarly journals Controlling the Thermal Stability of Kyanite-Based Refractory Geopolymers

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2903
Author(s):  
Juvenal Giogetti Nemaleu Deutou ◽  
Rodrigue Cyriaque Kaze ◽  
Elie Kamseu ◽  
Vincenzo M. Sglavo
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
High Strength ◽  
Treatment Temperature ◽  
Strength Development ◽  
Particle Sizes ◽  
Cold Setting ◽  
Thermal Stability Of ◽  
Geopolymer Composites ◽  
Refractory Composites

The present project investigated the thermal stability of cold-setting refractory composites under high-temperature cycles. The proposed route dealt with the feasibility of using fillers with different particle sizes and studying their influence on the thermo-mechanical properties of refractory geopolymer composites. The volumetric shrinkage was studied with respect to particle sizes of fillers (80, 200 and 500 µm), treatment temperature (1050–1250 °C) and amount of fillers (70–85 wt.%). The results, combined with thermal analysis, indicated the efficiency of refractory-based kyanite aggregates for enhancing thermo-mechanical properties. At low temperatures, larger amounts of kyanite aggregates promoted mechanical strength development. Flexural strengths of 45, 42 and 40 MPa were obtained for geopolymer samples, respectively, at 1200 °C, made with filler particles sieved at 80, 200 and 500 µm. In addition, a sintering temperature equal to 1200 °C appeared beneficial for the promotion of densification as well as bonding between kyanite aggregates and the matrix, contributing to the reinforcement of the refractory geopolymer composites without any sign of vitrification. From the obtained properties of thermal stability, good densification and high strength, kyanite aggregates are efficient and promising candidates for the production of environmentally friendly, castable refractory composites.

scholarly journals Assessment of the Rheological and Mechanical Properties of Geopolymer Concrete Comprising Fly Ash and Fluid Catalytic Cracking Residue as Aluminosilicate Precursor

2021 ◽  
Vol 11 (7) ◽  
pp. 3032
Author(s):  
Tuan Anh Le ◽  
Sinh Hoang Le ◽  
Thuy Ninh Nguyen ◽  
Khoa Tan Nguyen
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Flexural Strength ◽  
Catalytic Cracking ◽  
Fluid Catalytic Cracking ◽  
High Alumina ◽  
Geopolymer Concrete ◽  
Sem Images

The use of fluid catalytic cracking (FCC) by-products as aluminosilicate precursors in geopolymer binders has attracted significant interest from researchers in recent years owing to their high alumina and silica contents. Introduced in this study is the use of geopolymer concrete comprising FCC residue combined with fly ash as the requisite source of aluminosilicate. Fly ash was replaced with various FCC residue contents ranging from 0–100% by mass of binder. Results from standard testing methods showed that geopolymer concrete rheological properties such as yield stress and plastic viscosity as well as mechanical properties including compressive strength, flexural strength, and elastic modulus were affected significantly by the FCC residue content. With alkali liquid to geopolymer solid ratios (AL:GS) of 0.4 and 0.5, a reduction in compressive and flexural strength was observed in the case of geopolymer concrete with increasing FCC residue content. On the contrary, geopolymer concrete with increasing FCC residue content exhibited improved strength with an AL:GS ratio of 0.65. Relationships enabling estimation of geopolymer elastic modulus based on compressive strength were investigated. Scanning electron microscope (SEM) images and X-ray diffraction (XRD) patterns revealed that the final product from the geopolymerization process consisting of FCC residue was similar to fly ash-based geopolymer concrete. These observations highlight the potential of FCC residue as an aluminosilicate source for geopolymer products.

scholarly journals Experimental investigation on strength development of lime stabilized loess

RSC Advances ◽  
2019 ◽  
Vol 9 (34) ◽  
pp. 19680-19689 ◽  
Author(s):  
Liang Jia ◽  
Jian Guo ◽  
Zhidong Zhou ◽  
Yong Fu ◽  
Kai Yao
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Ground Improvement ◽  
Strength Development ◽  
Lime Stabilization

Lime stabilization has been widely used in pavement subbases and ground improvement, but the investigation of the mechanical properties and the microstructure of lime stabilized loess is still insufficient.

scholarly journals Mechanical and structural properties of composites made from recycled and virgin polyethylene terephthalate (PET) and metal chip or mesh wire

2019 ◽  
Vol 299 ◽  
pp. 06007
Author(s):  
Mircea Aurelian Antoniu Rusu ◽  
Sever-Adrian Radu ◽  
Catalin Moldovan ◽  
Codruta Sarosi ◽  
Ionela Amalia Mazilu (Moldovan) ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polyethylene Terephthalate ◽  
Processing Parameters ◽  
Sem Images ◽  
Major Drawback ◽  
Recycled Pet ◽  
Plastic Processing ◽  
Metal Chip ◽  
Intense Research ◽  
Properties Of Composites

Although polyethylene terephthalate (PET) is a champion of recycling, intense research is being done to find new solutions for using recycled plastic. This study aims to characterize the mechanical andstructural properties (SEM- scanning electron microscopy) of products made from recycled metal swarf or mesh wire with recycled plastic (PET) in comparison with virgin plastic. Samples manufactured from virgin and recycled PET are made by pressing and high temperature. The loss of mechanical properties ofproducts made from recycled plastic is a major drawback that influences their use. SEM images confirm that the dispersion and distribution of the PET phase is not very uniform. By addition of virgin plastic in various compositions with recycled plastic, processing parameters and mechanical properties can be optimized.

Sign in / Sign up

Export Citation Format

Share Document