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Full-Text Articles in Engineering

Inspection And Evaluation Of Dry Fibers In Thick Composites, Vinay Dayal, Sunil Chakrapani, Daniel Barnard Aug 2014

Inspection And Evaluation Of Dry Fibers In Thick Composites, Vinay Dayal, Sunil Chakrapani, Daniel Barnard

Sunil Kishore Chakrapani

This paper presents the investigation of dry fibers in thick composites. Dry fibers can be defined as lack of epoxy in localized regions. These local regions act as potential defects in thick composites under compressive loads and act as an initiation point for defects such as matrix cracking and delamination. Detection and characterization of dryness in glass/epoxy composites, with thickness greater than one inch, is presented in this paper. One inch samples with dry fibers were fabricated and tested. Detection is carried out with the help of air coupled ultrasonics in both through transmission and singled sided inspection. To characterize …


Research On Embedded Sensors For Concrete Health Monitoring Based On Ultrasonic Testing, Shifeng Huang, Mimi Li, Yuesheng Xu, Dongyu Xu, Xinchun Xie, Xin Cheng Jul 2014

Research On Embedded Sensors For Concrete Health Monitoring Based On Ultrasonic Testing, Shifeng Huang, Mimi Li, Yuesheng Xu, Dongyu Xu, Xinchun Xie, Xin Cheng

International Conference on Durability of Concrete Structures

In this article, embedded ultrasonic sensors were prepared using 1–3-type piezoelectric composite and piezoelectric ceramic as the piezoelectric elements, respectively. The frequency bandwidth of the novel embedded ultrasonic sensors was investigated. To obtain the relationship between the receiving ultrasonic velocity and compressive strength, as well as their response signals to crack damage, the sensors were fabricated and embedded into the cement mortar before testing. The results demonstrated that the piezoelectric composite sensor had wider frequency bandwidth than the piezoelectric ceramic sensor. The compressive strength and ultrasonic velocity had a positive linear relationship, with a correlation coefficient of 0.9216. The head …


Effect Of Accelerated Carbonation On Aod Stainless Steel Slag For Its Valorisation As A Co2-Sequestering Construction Material, Muhammad Salman, Özlem Cizer, Yiannis Pontikes, Rafael M. Santos, Ruben Snellings, Lucie Vandewalle, Bart Blanpain, Koen Van Balen Jun 2014

Effect Of Accelerated Carbonation On Aod Stainless Steel Slag For Its Valorisation As A Co2-Sequestering Construction Material, Muhammad Salman, Özlem Cizer, Yiannis Pontikes, Rafael M. Santos, Ruben Snellings, Lucie Vandewalle, Bart Blanpain, Koen Van Balen

Faculty Publications and Scholarship

Non-stabilized Argon Oxygen Decarburisation (AODNS) slag in powdered form was examined for its carbon dioxide sequestration capacity and for its potential utilization in the fabrication of high value building materials. The curing of the sample was carried out in two accelerated carbonation environments: i) in a carbonation chamber, maintained at atmospheric pressure, 22 °C, 5 vol.% CO2 and 80% RH; and ii) in a carbonation reactor, where the CO2 partial pressure (pCO2) and temperature could be further increased. In the carbonation chamber, an average compressive strength of over 20 MPa, on a 64 cm …


Strength Of Masonry Grout Made With Expanded Shale, Allison Tanner Mar 2014

Strength Of Masonry Grout Made With Expanded Shale, Allison Tanner

Theses and Dissertations

Light-weight aggregate has been used successfully for structural and non-structural applications, and its most common use has been in light-weight concrete. Limited research has been done on light-weight grout though and there are no standards in place. The research performed in this study is intended to increase the knowledge of light-weight grout specifically made with expanded shale aggregate. The research presented herein is a pilot study and consists of preliminary aggregate and grout testing that resulted in the mix design of six grout types: three fine grout designs and three coarse grout designs. Conventional normal-weight aggregate was employed in the …


Effects Of Heat Treatment On Oil Palm Shell Coarse Aggregates For High Strength Lightweight Concrete, Hilmi Mahmud Feb 2014

Effects Of Heat Treatment On Oil Palm Shell Coarse Aggregates For High Strength Lightweight Concrete, Hilmi Mahmud

Hilmi Mahmud

In this study, the effects of heat treatment on oil palm shell (OPS) coarse aggregates are evaluated for high strength lightweight concrete (HSLWC). OPS coarse aggregates are subjected to heat treatment at two temperature settings (60 and 150. °C) and duration of heat treatment (0.5 and 1. h). The reduction in density is found to be within the range of HSLWC when heat-treated OPS aggregates are added into the oil palm shell concrete (OPSC). The results reveal that workability of the OPSC increases with an increase in temperature and duration of heat treatment of the OPS aggregates. It is found …


Effects Of Using Silica Fume And Polycarboxylate-Type Superplasticizer On Physical Properties Of Cementitious Grout Mixtures For Semiflexible Pavement Surfacing, Hilmi Mahmud Jan 2014

Effects Of Using Silica Fume And Polycarboxylate-Type Superplasticizer On Physical Properties Of Cementitious Grout Mixtures For Semiflexible Pavement Surfacing, Hilmi Mahmud

Hilmi Mahmud

Semi-flexible pavement surfacing is a composite pavement that utilizes the porous pavement structure of the flexible bituminous pavement, which is subsequently grouted with appropriate cementitious materials. This study aims to investigate the compressive strength, flexural strength, and workability performance of cementitious grout. The grout mixtures are designed to achieve high strength and maintain flow properties in order to allow the cement slurries to infiltrate easily through unfilled compacted skeletons. A paired-sample t-test was carried out to find out whether water/cement ratio, SP percentages, and use of silica fume influence the cementitious grout performance. The findings showed that the replacement of …


Synergistic Toughening Of Hard, Nacre-Mimetic Mosi2 Coatings By Self-Assembled Hierarchical Structure, Jiang Xu, Xiaoli Zhao, Paul Munroe, Zonghan Xie Jan 2014

Synergistic Toughening Of Hard, Nacre-Mimetic Mosi2 Coatings By Self-Assembled Hierarchical Structure, Jiang Xu, Xiaoli Zhao, Paul Munroe, Zonghan Xie

Research outputs 2014 to 2021

Like many other intermetallic materials, MoSi2 coatings are typically hard, but prone to catastrophic failure due to their low toughness at ambient temperature. In this paper, a self-assembled hierarchical structure that closely resembles that of nacre (i.e., mother of pearl) was developed in a MoSi2 -based coating through a simple, yet cost-effective, depostion technique. The newly formed coating is tough and can withstand multiple indentations at high loads. Key design features responsible for this remarkable outcome were identified. They include a functionally graded multilayer featuring elastic modulus oscillation, varying sublayer thickness and a columnar structure that are able to attenuate …


Bio-Inspired And Low-Content Polymer Cement Mortar For Structural Rehabilitation, Nima Zohhadi Jan 2014

Bio-Inspired And Low-Content Polymer Cement Mortar For Structural Rehabilitation, Nima Zohhadi

Theses and Dissertations

Use of polymers as partial replacement for Portland cement in cement mortar and concrete can diminish several drawbacks of these composites such as low tensile strength and strain capacity, high permeability and low adhesion. Main reasons for the use of polymers are to improve damage tolerance, adhesion, and resistance to water permeation. Various polymers with a wide range of physical and mechanical properties have been used in fabrication of cementitious composites. Typical polymer content for such composites is 5% to 20% (by the weight of cement) for both mortar and concrete. There are also drawbacks associated with the use of …