Study on Pore Structure Characterization of Concrete at Different Ages by Thermoporometry

2013 ◽  
Vol 539 ◽  
pp. 178-183 ◽  
Author(s):  
Zheng Wu Jiang ◽  
Zi Long Deng ◽  
Nan Zhang
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
High Strength Concrete ◽  
High Strength ◽  
Structure Characterization ◽  
Strength Concrete ◽  
20 Nm ◽  
The Relationship ◽  
Curing Age

In this paper, pore structures and their changes of ordinary-strength concrete and high-strength concrete at different curing ages of 3, 28, 90 days were studied using thermoporometry, and the results were compared with those from MIP and NAD. The relationship between micro pores and porosity of concrete and its macroscopic properties was also studied. The results indicate that, compared to MIP, thermoporometry can characterize the features of pores with the diameter smaller than 100 nm in concrete accurately. The differences of macroscopic mechanical properties of concretes can be explained using the changes of their pore size distribution. After curing age of 28 days, the amount of pores with the diameter higher than 20 nm in high strength concrete changes little, but it decreases gradually in ordinary strength concrete. And pores with diameter smaller than 20 nm in concrete have little influence on the macroscopic mechanical property of concrete.

Performance of Ultra-High Strength Concrete Containing Different Types of Fibers

2015 ◽  
Vol 1120-1121 ◽  
pp. 1491-1495
Author(s):  
Wei Qin Li ◽  
Yuan Peng ◽  
Xue Yun He ◽  
Xiong Wu ◽  
Liang Huo
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
High Strength Concrete ◽  
Steel Fiber ◽  
High Strength ◽  
Equivalent Diameter ◽  
Fine Aggregate ◽  
Volume Stability ◽  
Strength Concrete ◽  
Different Types

Influence of fiber on workability and mechanical property of ultra-high strength concrete (UHSC) were studied. Results show that, when amount of steel fiber (Equivalent diameter is 0.2mm; nominal length is 13mm; Tensile strength is 2850MPa )substituting fine aggregate is 120kg/m3, UHSC could have the best mechanical properties of 139.0MPa compressive strength, 18.0MPa flexural strength, and 10.0MPa Splitting strength; steel fiber cannot improve volume stability of UHSC.

scholarly journals MECHANICAL PROPERTIES OF HIGH STRENGTH CONCRETE AT HIGH TEMPERATURES

2008 ◽  
Vol 73 (624) ◽  
pp. 341-347 ◽  
Author(s):  
Masashi MATSUDO ◽  
Hirokazu NISHIDA ◽  
Takahiro OHTSUKA ◽  
Takeo HIRASHIMA ◽  
Takeo ABE
Keyword(s):  
Mechanical Properties ◽  
High Temperatures ◽  
High Strength Concrete ◽  
High Strength ◽  
Strength Concrete

Comparison Analysis on the Mechanical Properties of HSC and NSC after the Action of High Temperatures

2014 ◽  
Vol 1014 ◽  
pp. 49-52
Author(s):  
Xiao Ping Su
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
High Temperatures ◽  
High Strength Concrete ◽  
Elasticity Modulus ◽  
Strain Curve ◽  
Peak Stress ◽  
High Strength ◽  
Peak Strain ◽  
Strength Concrete

With the wide application of high strength concrete in the building construction,the risk making concrete subject to high temperatures during a fire is increasing. Comparison tests on the mechanical properties of high strength concrete (HSC) and normal strength concrete (NSC) after the action of high temperature were made in this article, which were compared from the following aspects: the peak stress, the peak strain, elasticity modulus, and stress-strain curve after high temperature. Results show that the laws of the mechanical properties of HSC and NSC changing with the temperature are the same. With the increase of heating temperature, the peak stress and elasticity modulus decreases, while the peak strain grows rapidly. HSC shows greater brittleness and worse fire-resistant performance than NSC, and destroys suddenly. The research and evaluation on the fire-resistant performance of HSC should be strengthened during the structural design and construction on the HSC buildings.

scholarly journals Effect of Locally Available Wheat Straw Ash in Developing High Strength Concrete

2021 ◽  
pp. 19-28
Author(s):  
Muhammad Armaghan Siffat ◽  
Muhammad Ishfaq ◽  
Afaq Ahmad ◽  
Khalil Ur Rehman ◽  
Fawad Ahmad
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Wheat Straw ◽  
High Strength Concrete ◽  
High Strength ◽  
Optimum Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Strength Concrete ◽  
Straw Ash

This study is supervised to assess the characteristics of the locally available wheat straw ash (WSA) to consume as a substitute to the cement and support in enhancing the mechanical properties of concrete. Initially, after incineration at optimum temperature of 800°C for 0.5, the ash of wheat straw was made up to the desirable level of fineness by passing through it to the several grinding cycles. Subsequently, the X-ray fluorescence (XRF) along with X-ray diffraction (XRD) testing conducted on ash of wheat straw for the evaluation its pozzolanic potential. Finally, the specimens of concrete were made by consuming 10% and 20% percentages of wheat straw ash as a replacement in concrete to conclude its impact on the compressive strength of high strength concrete. The cylinders of steel of dimensions 10cm diameter x 20cm depth were acquired to evaluate the compressive strength of high strength concrete. The relative outcomes of cylinders made of wheat straw ash substitution presented the slight increase in strength values of the concrete. Ultimately, the C-100 blends and WSA aided cement blends were inspected for the rheology of WSA through FTIR spectroscopy along with Thermogravimetric technique. The conclusions authenticate the WSA potential to replace cement in the manufacturing of the high strength concrete.

scholarly journals Experimental Investigation on Mechanical Properties of Hybrid Steel and Polyethylene Fiber-Reinforced No-Slump High-Strength Concrete

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Tian-Feng Yuan ◽  
Jin-Young Lee ◽  
Kyung-Hwan Min ◽  
Young-Soo Yoon
Keyword(s):  
Mechanical Properties ◽  
Energy Dissipation ◽  
Flexural Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Fiber Reinforced ◽  
Flexural Toughness ◽  
Strength Concrete ◽  
Polyethylene Fiber ◽  
Energy Dissipation Capacity

This paper presents experimental investigations on the mechanical properties of no-slump high-strength concrete (NSHSC), such as the compressive and flexural strength. First, to determine the proper NSHSC mixtures, the compressive and flexural strength of three different water-to-binder ratios (w/b) of specimens with and without polyethylene (PE) fiber was tested at test ages. Then, the effect of hybrid combinations of PE fiber and steel fiber (SF) on the compressive strength, flexural strength, flexural toughness, and flexural energy dissipation capacity was experimentally investigated. Furthermore, the various hybrid fiber-reinforced NSHSCs were evaluated, and their synergy was calculated, after deriving the benefits from each of the individual fibers to exhibit a synergetic response. The test results indicate that a w/b of 16.8% with or without fibers had lower strength and flexural strength (toughness) than those of other mixtures (w/b of 16.4% and 17.2%). Specimens with a hybrid of SF and short PE fibers exhibited a higher compressive and flexural strength, flexural toughness, energy dissipation capacity, and fiber synergy in all considered instances.

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