scholarly journals Tests on the Mechanical Properties of Corroded Cement Mortar after High Temperature

2020 ◽  
Vol 6 (3) ◽  
pp. 459-469 ◽  
Author(s):  
Xiong Liang-Xiao ◽  
Chen Cong
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Temperature ◽  
Sodium Sulfate ◽  
Sea Water ◽  
Cement Mortar ◽  
Peak Stress ◽  
Sulfate Solution ◽  
Sodium Sulfate Solution ◽  
Compression Tests

Durability of cement mortar and concrete materials under sea water condition is always an important research topic. The objective of this work is to understand the mechanical properties of corroded cement mortar after high temperature, the cement mortar specimens after high temperature were placed in water and sodium sulfate solution, and then the uniaxial compression tests were carried out on the cement mortar specimens after corroded. Test results show that both the differences of compressive strength and strain at the peak stress after high temperature caused by high temperature, are relatively small when the specimens are eroded in water, and the differences are relatively high when the specimens are eroded in sodium sulfate solution. The compressive strength of the cement mortar specimens under normal temperature eroded in sodium sulfate solution is highest, and that eroded in water is lowest. The compressive strength of specimen after high temperature eroded in water is highest and that eroded in sodium sulfate solution is lowest. The strain at the peak stress of specimen, whether after high temperature or not, is highest when eroded in sodium sulfate solution, and that eroded in water is lowest. At present, there are few research results about the mechanical properties of concrete first after high temperature and then after sea water corrosion. The work in this paper can enrich the results in this area.

scholarly journals Mechanical Properties of Cement Mortar after Dry–Wet Cycles and High Temperature

2020 ◽  
Vol 6 (5) ◽  
pp. 1031-1038
Author(s):  
Xiong Liang-Xiao ◽  
Song Xiao-Gang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Temperature ◽  
Cement Mortar ◽  
Peak Stress ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Factors Affecting ◽  
Temperature Exposure ◽  
Compressive Tests

The dry–wet cycle and high temperature exposure are important factors affecting the normal use and durability of concrete structures. The objective of this work is to investigate the mechanical properties of cement mortar specimens after combinations of dry–wet cycles and high temperature exposures, uniaxial compressive tests on cement mortar specimens were carried out under the following two sets of conditions: (1) high temperature treatment followed by a dry–wet cycle and (2) a dry–wet cycle followed by high temperature treatment. The results show that the compressive strength of specimens increases with the number of dry–wet cycles. After a dry–wet cycle and then a high temperature treatment procedure, the compressive strength of a specimen will first decrease and then increase with the number of dry–wet cycles. The strain at the peak stress of cement mortar decreases as the number of dry–wet cycles increases. At present, there are few research results about the mechanical properties of concrete first after combinations of dry–wet cycles and high temperature exposures. The work in this paper can enrich the results in this area.

scholarly journals Mechanical Degradation and Thermal Decomposition of Ethylene-Vinyl Acetate (EVA) Polymer-Modified Cement Mortar (PCM) Exposed to High-Temperature

2019 ◽  
Vol 11 (2) ◽  
pp. 500 ◽  
Author(s):  
Hyung-Jun Kim ◽  
Jae-Yeon Park ◽  
Heong-Won Suh ◽  
Beom-Yeon Cho ◽  
Won-Jun Park ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Decomposition ◽  
Compressive Strength ◽  
High Temperature ◽  
Vinyl Acetate ◽  
Cement Mortar ◽  
Ethylene Vinyl Acetate ◽  
Mechanical Degradation ◽  
Rc Structures ◽  
Cement Ratio

A polymer-modified cement mortar (PCM) is widely used as a repair material for reinforced concrete (RC) structures owing to its excellent strength and durability. However, considering the maintenance of the RC structures and the use period of the structures, the change in the physical properties of the PCM should be evaluated when exposed to various high-temperature environments, such as fires. In this study, the degradation of the mechanical properties (compressive strength and modulus of elasticity), thermal decomposition of the PCM in various high-temperature environments, and the change in the pore structure of the PCM after exposure to high temperatures were quantitatively investigated. A mechanical property evaluation of PCM was performed under three heating conditions: (i) heating in a compression tester, (ii) heating the specimen in an oven to a predetermined temperature and then moving it to a compression tester preheated to the same temperature, and (iii) cooling to room temperature after heating. In the experiment, a PCM specimen was prepared by changing the polymer–cement ratio (polymer content) of ethylene-vinyl acetate (EVA), the most commonly used polymer, to perform a high-temperature sectional test from 200 to 800 °C. In addition, to investigate the change in the PCM mechanical properties in the high-temperature region, in terms of the pyrolysis of EVA, the porosity change and mass change were examined using thermal analysis and mercury intrusion porosimetry. Before heating, the compressive strength of the PCM increased with the EVA content up to 10 % of the polymer–cement ratio. Under the cooling conditions after heating up to 200 °C, the mechanical performance of the PCM was restored, whereas the degradation of the mechanical properties of the PCM without cooling was more pronounced. Furthermore, the mass loss, heat flow, and the total porosity of the PCM increased as the EVA content increased, which is correlated with the degradation of the mechanical properties of the PCM.

scholarly journals Combustion and Mechanical Properties of Polymer-Modified Cement Mortar at High Temperature

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Hyung-Jun Kim ◽  
Won-Jun Park
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Temperature ◽  
Heat Release ◽  
Cement Mortar ◽  
Mass Loss Rate ◽  
Polymer Content ◽  
Cement Ratio ◽  
Combustion Properties ◽  
Polymer Type

Although polymer-modified cement mortar (PCM) has been extensively used as finishing and repairing material, it is necessary to understand its combustion properties and mechanical properties at high temperature. This study evaluated the combustion characteristics with varying experimental parameters such as polymer type, unit polymer content, polymer-cement ratio, and thickness of the specimen. This study also evaluated the compressive strength and elastic modulus of PCMs with focus on the effects of the type of polymer, unit polymer content, and polymer-cement ratio. As a result, the incombustibility of the PCM was in the following order: SBR < VVA < EVA. After heating end, the mass loss rate of the PCM was less than 30%, regardless of the polymer type, unit polymer content, and W/C. In heat release rate test, the higher the unit polymer content, the greater the total heat release, regardless of the difference in W/C. The PAE series showed excellent fire resistance in the temperature range of 200~400°C. PCMs with a unit polymer content of 5%, modified with EVA and PAE, showed outstanding compressive strength at 200~400°C. At elevated temperature, the modulus of elasticity of PCM declined with an increase in the unit polymer content, regardless of the polymer type.

Impact of sodium sulfate solution on mechanical properties and structure of fly ash based geopolymers

2014 ◽  
Vol 48 (3) ◽  
pp. 683-697 ◽  
Author(s):  
Zvezdana Baščarević ◽  
Miroslav Komljenović ◽  
Zoran Miladinović ◽  
Violeta Nikolić ◽  
Nataša Marjanović ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Sodium Sulfate ◽  
Sulfate Solution ◽  
Sodium Sulfate Solution

scholarly journals Unconfined and Triaxial Compression Tests on Hollowed Cylindrical Sandstones to Explore the Infilling Effects on the Deformation and Mechanical Behaviors

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yong Liu ◽  
Xiao Li ◽  
Lei Weng ◽  
Qiuhong Wu ◽  
Haifan Wang
Keyword(s):  
Mechanical Properties ◽  
Carrying Capacity ◽  
Cement Mortar ◽  
Shear Fracture ◽  
Triaxial Compression ◽  
Peak Stress ◽  
Surrounding Rock ◽  
Compression Tests ◽  
Failure Patterns ◽  
Compression Condition

In practical engineering, the mechanical properties of the surrounding rock often reflect the bearing capacity of the support. To investigate the relations between the surrounding rock and the support, solid specimens, hollowed cylinders, and hollowed cylinders filled with two kinds of cement mortars are tested under unconfined and conventional triaxial compressions. The effects of the infilling on the stress-strain curves, deformation features, mechanical properties, and failure patterns are schematically investigated. The results show that under the triaxial compression condition, each infilled specimen exhibits obvious residual carrying capacity though a slight stress drop occurs after the peak stress. The cement mortar exerts a positive effect on the carrying capacity of the rock, and the infilling having a higher strength and stiffness contributes to a more pronounced enhancement of the overall strength of the specimens. Under the triaxial compression condition, merely a dominated shear fracture can be seen on the surfaces, and with relatively high confining pressure (σ3 = 20 and 30 MPa), both the rock and cement mortar were cut into two parts by the dominated shear fracture. The laboratory tests in this study provide a simple and feasible way of investigating the interaction of the support system with the surrounding rock.

Experimental Study on Accelerated Speed of Concrete Sulfate Attack

2012 ◽  
Vol 204-208 ◽  
pp. 3754-3759
Author(s):  
Hong Fei Liu ◽  
Fa Jun Huang
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Sodium Sulfate ◽  
Sulfate Solution ◽  
Solution Concentration ◽  
Sulfate Attack ◽  
Sodium Sulfate Solution ◽  
Insignificant Difference ◽  
Compressive Strength Of Concrete

Through test on compressive strength of concrete and mass changes, the effects of solution concentration and temperature on speed of concrete sulfate attack were investigated. The results show that, the speed of attack is accelerated with increasing concentration and temperature, as well as the decreasing of the size of the specimen, sulfate attack speed at 45 °C sodium sulfate solution soak with wet and dry cycle is insignificant difference with at 20 °C.It is suitable to adopt compressive strength as the assessing criterion of the sodium sulfate attack.

Incorporation of Iraqi Rocks in the Production of Eco-Friendly Cement Mortar

2020 ◽  
Vol 38 (10A) ◽  
pp. 1522-1530
Author(s):  
Rawnaq S. Mahdi ◽  
Aseel B. AL-Zubidi ◽  
Hassan N. Hashim
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Water Absorption ◽  
Structural Properties ◽  
Mechanical Milling ◽  
Cement Mortar ◽  
Cement Mortars

This work reports on the incorporation of Flint and Kaolin rocks powders in the cement mortar in an attempt to improve its mechanical properties and produce an eco-friendly mortar. Flint and Kaolin powders are prepared by dry mechanical milling. The two powders are added separately to the mortars substituting cement partially. The two powders are found to improve the mechanical properties of the mortars. Hardness and compressive strength are found to increase with the increase of powders constituents in the cement mortars. In addition, the two powders affect water absorption and thermal conductivity of the mortar specimens which are desirable for construction applications. Kaolin is found to have a greater effect on the mechanical properties, water absorption, and thermal conductivity of the mortars than Flint. This behavior is discussed and analyzed based on the compositional and structural properties of the rocks powders.

scholarly journals Mechanical Behavior of Brick Masonry in an Acidic Atmospheric Environment

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2694 ◽  
Author(s):  
Shansuo Zheng ◽  
Lihua Niu ◽  
Pei Pei ◽  
Jinqi Dong
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Acid Rain ◽  
Cement Mortar ◽  
Brick Masonry ◽  
Atmospheric Environment ◽  
Peak Strain ◽  
Lime Mortar ◽  
Attenuation Model

In order to evaluate the deterioration regularity for the mechanical properties of brick masonry due to acid rain corrosion, a series of mechanical property tests for mortars, bricks, shear prisms, and compressive prisms after acid rain corrosion were conducted. The apparent morphology and the compressive strength of the masonry materials (cement mortar, cement-lime mortar, cement-fly ash mortar, and brick), the shear behavior of the masonry, and the compression behavior of the masonry were analyzed. The resistance of acid rain corrosion for the cement-lime mortar prisms was the worst, and the incorporation of fly ash into the cement mortar did not improve the acid rain corrosion resistance. The effect of the acid rain corrosion damage on the mechanical properties for the brick was significant. With an increasing number of acid rain corrosion cycles, the compressive strength of the mortar prisms, and the shear and compressive strengths of the brick masonry first increased and then decreased. The peak stress first increased and then decreased whereas the peak strain gradually increased. The slope of the stress-strain curve for the compression prisms gradually decreased. Furthermore, a mathematical degradation model for the compressive strength of the masonry material (cement mortar, cement-lime mortar, cement-fly ash mortar, and brick), as well as the shear strength attenuation model and the compressive strength attenuation model of brick masonry after acid rain corrosion were proposed.

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