scholarly journals Material characterization of geopolymer mortar for its beneficial use in composite construction

2021 ◽  
Vol 5 ◽  
pp. 174-185
Author(s):  
Joachim Juhart ◽  
Christopher Gößler ◽  
Cyrill Grengg ◽  
Florian Mittermayr ◽  
Ognjen Rudic ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Autogenous Shrinkage ◽  
Correlation Method ◽  
Drying Shrinkage ◽  
Image Correlation ◽  
Strength Development ◽  
Ambient Conditions ◽  
Dry Conditions ◽  
Basic Characteristics

This paper investigates material properties of metakaolin/slag-based geopolymer mortar (GPM), relevant for composite action with conventional Portland cement-based concrete (PCC). GPM formulations with different workability (soft and stiff-plastic consistencies) were developed and characterized with regard to their compressive and tensile strength development over time, their shrinkage behaviour during hardening under different ambient conditions, as well as their thermal expansion. With the experimental data obtained, a coefficient of thermal expansion and equations for predicting the strength development were calculated. The GPMs exhibited significant autogenous shrinkage and drying shrinkage. Additionally, high very early shrinkage, tested by a new image correlation method, occurred immediately after setting under dry conditions. Thereby, the observed extent of early shrinkage strongly depended on the specimens’ thicknesses. Furthermore, the basic characteristics of autogenous and drying shrinkage of GPM were enlightened and compared to PCC.

scholarly journals Characterizing the Performance of Ternary Concrete Mixtures Involving Slag and Metakaolin

2020 ◽  
Vol 5 (2) ◽  
pp. 14
Author(s):  
Matthew S. Sullivan ◽  
Mi G. Chorzepa ◽  
Stephan A. Durham
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Fly Ash ◽  
Coefficient Of Thermal Expansion ◽  
Drying Shrinkage ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Ternary Mixtures ◽  
Modulus Of Rupture ◽  
Ternary Blends

Ternary blends of cementitious materials are investigated. A cement replacement level of 45% is used for all ternary mixtures consisting of 15% metakaolin and 30% slag replacements. Three metakaolin and two blast furnace slag, referred to as ‘slag’ for short, products commercially available are used to compare performance in ternary blends. A mixture with a 45% fly ash replacement is included to serve as a benchmark for performance. The control mixture contains 422 kg of cement per cubic meter of concrete, and a water-to-cementitious material ratio of 0.43 is used for all mixtures with varying dosages of superplasticizer to retain workability. Mixtures are tested for mechanical properties, durability, and volumetric stability. Mechanical properties include compression, split-cylinder tension, modulus of rupture, and dynamic Young’s modulus. Durability measures are comprised of rapid chloride-ion penetrability, sulfate resistance, and alkali–silica reactivity. Finally, the measure of dimensional stability is assessed by conducting drying shrinkage and coefficient of thermal expansion tests. Results indicate that ternary mixtures including metakaolin perform similarly to the control with respect to mechanical strength. It is concluded that ternary blends perform significantly better than both control and fly ash benchmark in tests measuring durability. Furthermore, shrinkage is reduced while the coefficients of thermal expansion are slightly higher than control and the benchmark.

Experimental Inverstigation on Thermal Expansion Coefficients of SnO2 Thin Film

2012 ◽  
Vol 591-593 ◽  
pp. 965-968
Author(s):  
Jing Wang ◽  
Hong Lai Li ◽  
Mei Hua Liu
Keyword(s):  
Thin Film ◽  
Thermal Expansion ◽  
Real Time ◽  
Correlation Method ◽  
Wide Band ◽  
Electric Heating ◽  
Image Correlation ◽  
Real Time System ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

As a kind of wide band-gap material focused on in recent years, SnO2 thin Film with μm level has been widely applied in many fields such as solar cells, electric heating devices, transparent electrodes, and gas sensors, ect. This paper develops a real-time system to measure thermal expansion coefficients of SnO2 thin film, which can obtain directly surface morphology information of the samples. Micro-imaging and digital image correlation method is adopted to investigate the correlation by comparing the object surface image before deformation with that after deformation. Because of the lower demand for measurement environment and no damage to object, it’s easy to acquire on-line images, calculate synchronously and display real-time results. In the paper, thermal expansion coefficients of SnO2 thin film are determined in situ with change of the temperature. Both of ceramic and SnO2 thin film have shown anisotropy thermal expansion, thermal and residual stress appears between the ceramic substrate and SnO2 thin film as a result of thermal expansion coefficients mismatch. According to experimental results, the maximum stress values can be calculated between film and substrate and inside the substrate.

Study on the Effect of WC Size on the Thermal Expansion Coefficient of WC/Cu Composites

2013 ◽  
Vol 275-277 ◽  
pp. 1597-1600 ◽  
Author(s):  
Hai Yu ◽  
Rong Xin Guo ◽  
Hai Ting Xia ◽  
Feng Yan ◽  
Yu Bo Zhang
Keyword(s):  
Particle Size ◽  
Thermal Expansion ◽  
Powder Metallurgy ◽  
Digital Image Correlation ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Digital Image ◽  
Correlation Method ◽  
Image Correlation ◽  
Powder Metallurgy Method

Abstract: In order to study the effect of WC size on the thermal expansion coefficient of WC/Cu composites after anneal, WC/Cu composites with different WC particle size were prepared by powder metallurgy method. In this paper the thermal expansion coefficient of WC/Cu composites were measured by digital image correlation method. The results show that the thermal expansion coefficient increased with the increasing of temperature and the particle size.

scholarly journals Short-Term Deformability of Three-Dimensional Printable EVA-Modified Cementitious Mortars

2019 ◽  
Vol 9 (19) ◽  
pp. 4184 ◽  
Author(s):  
Jaeheum Yeon
Keyword(s):  
Thermal Expansion ◽  
Modulus Of Elasticity ◽  
Coefficient Of Thermal Expansion ◽  
Compressive Strain ◽  
Three Dimensional ◽  
Drying Shrinkage ◽  
Ethylene Vinyl Acetate ◽  
Short Term ◽  
Cement Ratio ◽  
Negative Impacts

This study experimentally examined the deformability of cementitious mortars modified with ethylene-vinyl acetate (EVA) for use in extrusion-based additive construction. The research was based on the author’s previous study of the properties of fresh EVA-modified cementitious mixtures for use in additive construction via extrusion. The particular focus was on these mortars’ short-term deformation factors, including the modulus of elasticity, drying shrinkage, and thermal expansion. The experimental results indicate that as the EVA/cement ratio was increased, the compressive strength and elastic modulus tended to decrease but the maximum compressive strain increased. At 28 days, the drying shrinkage tended to increase as the EVA/cement ratio was increased. The coefficient of thermal expansion was also found to increase as the EVA/cement ratio was increased. A very high correlation was found between these three deformation factors and the EVA/cement ratio. Given these results, it was determined that the addition of EVA powder to EVA-modified cementitious mortars used in extrusion-based additive construction could adversely affect their short-term deformation factors. However, increasing the EVA/cement ratio resulted in a decrease in the modulus of elasticity, thereby reducing the level of stress caused by drying shrinkage and thermal expansion. This effect will eventually lead to improvements in the degree of extensibility, thereby offsetting the negative impacts. However, it is still desirable to minimize the EVA/cement ratio to the extent that adequate properties for the fresh material can be obtained.

Investigation of Hygroscopic Swelling of Polymers in Freezing Temperature

2007 ◽  
Author(s):  
Seungbae Park ◽  
Haojun Zhang
Keyword(s):  
Thermal Expansion ◽  
Glass Transition ◽  
Transition Temperature ◽  
Room Temperature ◽  
Correlation Method ◽  
Freezing Temperature ◽  
Image Correlation ◽  
Temperature Dependent ◽  
Hygroscopic Swelling ◽  
Most Significant Change

It is well known that coefficients of thermal expansion and hygroscopic swelling vary with temperature. The most significant change takes place at the glass transition temperature of a polymer. The phenomenon of temperature-dependent CHS has been studied by several authors [1, 2] in polymers and polymer-based composites mainly at room temperature and above. However, effect of freezing temperature on hygroscopic swelling of polymers has not been demonstrated. In this study, the behavior of CHS at and below freezing temperature is investigated. Reported results are obtained using a new CHS measurement technique, the digital image correlation method.

scholarly journals Thermal expansion coefficient determination of polylactic acid using digital image correlation

2018 ◽  
Vol 32 ◽  
pp. 01007 ◽  
Author(s):  
Adrian - Ioan Botean
Keyword(s):  
Thermal Expansion ◽  
Digital Image Correlation ◽  
Thermal Expansion Coefficient ◽  
Polylactic Acid ◽  
Expansion Coefficient ◽  
Digital Image ◽  
Linear Thermal Expansion Coefficient ◽  
Linear Thermal Expansion ◽  
Correlation Method ◽  
Image Correlation

This paper aims determining the linear thermal expansion coefficient (CTE) of polylactic acid (PLA) using an optical method for measuring deformations called digital image correlation method (DIC). Because PLA is often used in making many pieces with 3D printing technology, it is opportune to know this coefficient to obtain a higher degree of precision in the construction of parts and to monitor deformations when these parts are subjected to a thermal gradient. Are used two PLA discs with 20 and 40% degree of filling. In parallel with this approach was determined the linear thermal expansion coefficient (CTE) for the copper cylinder on the surface of which are placed the two discs of PLA.

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