Static, dynamic mechanical properties and microstructure characteristics of ultra-high performance cementitious composites

2012 ◽  
Vol 19 (3) ◽  
pp. 237-245 ◽  
Author(s):  
Wenhua Zhang ◽  
Yunsheng Zhang ◽  
Guorong Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Performance ◽  
Steel Fiber ◽  
Construction Material ◽  
Dynamic Mechanical Properties ◽  
Fine Aggregate ◽  
Dynamic Impact ◽  
Dynamic Mechanical ◽  
Reactive Powder

AbstractA new type of construction material named ultra-high performance cementitious composite (UHPCC) was developed in order to reduce the production cost and energy consumption of reactive powder concrete (RPC). Six different mixture proportions of UHPCC were designed, and their properties, including workability (slump test), static mechanical properties (compressive strength and flexure strength), and dynamic mechanical properties (dynamic compressive strength, toughness and fracture pattern), were investigated. Finally, the microstructure of the UHPCC was studied. The experiment result indicate that the compressive and flexural strength of UHPCC can reach 150–200 MPa and 15–50 MPa under standard curing conditions, respectively, which is close to RPC200. Besides, the steel fiber has significant improvement on mechanical properties of UHPCC. The dynamic impact test results show that UHPCC has obvious strain rate effects. Besides, UHPCC exhibits excellent properties to resist dynamic impact. The microstructure investigation showed that UHPCC has dense microstructures and very strong bonds of the interfacial transition zone between cementitious paste and fine aggregate steel fiber.

Tests on Mechanical Properties and Anti-Penetration Performance of Steel-Fiber Reactive Powder Concrete

2013 ◽  
Vol 671-674 ◽  
pp. 1761-1765
Author(s):  
Yong Liu ◽  
Chun Ming Song ◽  
Song Lin Yue
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Steel Fiber ◽  
Reactive Powder Concrete ◽  
Calculation Results ◽  
Reactive Powder ◽  
Penetration Tests

In order to get mechanical properties ,some RPC samples with 5% steel fiber are tested, many groups data were obtained such as compressive strength, shear strength and fracture toughness. And a group of tests on RPC with 5% steel-fiber under penetration were also conducted to validate the performance to impact. The penetration tests are carried out by the semi-AP projectiles with the diameter of 57 mm and earth penetrators with the diameter of 80 mm, and velocities of the two kinds of projectiles are 300～600 m/s and 800～900 m/s, respectively. By contrast between the experimental data and the calculation results of C30 reinforced concrete by using experiential formula under penetration, it shows that the resistance of steel-fiber RPC to penetration is 3 times as that of general C30 reinforced concrete.

scholarly journals Research on the Dynamic Mechanical Properties and Energy Dissipation of Expansive Soil Stabilized by Fly Ash and Lime

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Sheng-quan Zhou ◽  
Da-wei Zhou ◽  
Yong-fei Zhang ◽  
Wei-jian Wang ◽  
Dongwei Li
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Expansive Soil ◽  
Dynamic Mechanical Properties ◽  
Test Results ◽  
Absorbed Energy ◽  
Dynamic Mechanical ◽  
Stabilized Soil ◽  
Dynamic Compressive Strength

To probe into the dynamic mechanical properties of expansive soil stabilized by fly ash and lime under impact load, the split-Hopkinson pressure bar (SHPB) test was carried out in this study. An analysis was made on the dynamic mechanical property and final fracture morphology of stabilized soil, and the failure mechanism was also explored from the perspective of energy dissipation. According to the test results, under the impact pressure of 0.2 MPa, plain soil and pure fly ash-stabilized soil exhibit strong plasticity. After the addition of lime, the stabilized soil shows obvious brittle failure. The dynamic compressive strength and absorbed energy of stabilized soil first increase and then decrease with the change of mix proportions. Both the dynamic compressive strength and the absorbed energy reach the peak value at the content of 20% fly ash and 5% lime (20% F + 5% L). In the process of the test, most of the incident energy is reflected back to the incident bar. The absorbed energy of stabilized soil increases linearly with the rise of dynamic compressive strength, while the absorbed energy is negatively correlated with the fractal dimension. The fractal dimension of pore morphology of the plain soil is lower than that of the fly ash-lime combined stabilized soil when it comes to the two different magnification ratios. The test results indicate that the modifier content of 20% F + 5% L can significantly improve the dynamic mechanical properties of the expansive soil.

scholarly journals Comparative Analysis of Static and Dynamic Mechanical Behavior for Dry and Saturated Cement Mortar

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3299 ◽  
Author(s):  
Ayyaz Mustafa ◽  
Mohamed A. Mahmoud ◽  
Abdulazeez Abdulraheem ◽  
Sarfaraz A. Furquan ◽  
Ayman Al-Nakhli ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Comparative Analysis ◽  
Mechanical Behavior ◽  
Cement Mortar ◽  
Water Saturation ◽  
Dynamic Compression ◽  
Impact Resistance ◽  
Dynamic Mechanical Properties ◽  
Dynamic Mechanical

Deformational and breakage behaviors of concrete and cement mortar greatly influence various engineering structures, such as dams, river bridges, ports, tunnels, and offshore rig platforms. The mechanical and petrophysical properties are very sensitive to water content and are controlled by the liquid part in pore spaces to a large extent. The objective of this paper is to investigate the water saturation effect on the strength characteristics and deformability of cement mortar under two loading conditions, static and dynamic compression. A set of cement mortar samples was prepared and tested to study the mechanical behavior in dry and saturated states. The first part of the research incorporates the study of static mechanical properties for dry and brine-saturated cement mortar through uniaxial compressive strength tests (UCS). Second, drop-weight impact experiments were carried out to study the dynamic mechanical properties (impact resistance, deformation pattern, and fracture geometry) for dry and saturated cases. The comparative analysis revealed that water saturation caused substantial changes in compressive strength and other mechanical characteristics. Under static loading, water saturation caused a reduction in strength of 36%, and cement mortar tended to behave in a more ductile manner as compared to dry samples. On the contrary, under dynamic loading conditions, water saturation resulted in higher impact resistance and fracture toughness as compared to dry conditions. In addition, fractures could propagate to smaller depths as compared to dry case. The study will help resolve many civil, mining, and petroleum engineering problems where cement structures undergo static as well as dynamic compression, especially in a hydraulic environment where these structures interact with the water frequently. To the best of our knowledge, the effect of water saturation on the dynamic mechanical properties of cement mortar has not been well understood and reported in the literature.

scholarly journals Effect of Short Fiber Reinforcement on Mechanical Properties of Hybrid Phenolic Composites

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Sembian Manoharan ◽  
Bhimappa Suresha ◽  
Govindarajulu Ramadoss ◽  
Basavaraj Bharath
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Loss Modulus ◽  
Basalt Fiber ◽  
Barium Sulphate ◽  
Dynamic Mechanical Properties ◽  
Damping Factor ◽  
X Ray ◽  
Weight Percentage ◽  
Dynamic Mechanical

Fiber plays an important role in determining the hardness, strength, and dynamic mechanical properties of composite material. In the present work, enhancement of viscoelastic behaviour of hybrid phenolic composites has been synergistically investigated. Five different phenolic composites, namely, C1, C2, C3, C4, and C5, were fabricated by varying the weight percentage of basalt and aramid fiber, namely, 25, 20, 15, 10, and 5% by compensating with barium sulphate (BaSO4) to keep the combined reinforcement concentration at 25 wt%. Hardness was measured to examine the resistance of composites to indentation. The hardness of phenolic composites increased from 72.2 to 85.2 with increase in basalt fiber loading. Composite C1 (25 wt% fiber) is 1.2 times harder than composite C5. Compression test was conducted to find out compressive strength of phenolic composites and compressive strength increased with increase in fiber content. Dynamic mechanical analysis (DMA) was carried out to assess the temperature dependence mechanical properties in terms of storage modulus (E′), loss modulus (E′′), and damping factor (tan δ). The results indicate great improvement of E′ values and decrease in damping behaviour of composite upon fiber addition. Further X-ray powder diffraction (XRD) and energy-dispersive X-ray (EDX) analysis were employed to characterize the friction composites.

Quasi-Static, Dynamic Compressive Properties and Deformation Mechanisms of Ti-6Al-4V Alloy with Gradient Structure

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1928
Author(s):  
Lei Lei ◽  
Yongqing Zhao ◽  
Qinyang Zhao ◽  
Shewei Xin ◽  
Cong Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Dynamic Compression ◽  
Dynamic Mechanical Properties ◽  
Coarse Grained ◽  
Lateral Side ◽  
Gradient Structure ◽  
Deformation Bands ◽  
Compressive Properties ◽  
Dynamic Mechanical

Gradient structure metals have good comprehensive properties of strength and toughness and are expected to improve the dynamic mechanical properties of materials. However, there are few studies on the dynamic mechanical properties of gradient structured materials, especially titanium alloys. Therefore, in this study, ultrasonic surface rolling is used to prepare a gradient structure layer on the surface of Ti-6Al-4V, and the quasi-static and dynamic compressive properties of coarse-grained Ti-6Al-4V (CG Ti64) and gradient-structured Ti-6Al-4V (GS Ti64) are investigated. The results show that a GS with a thickness of 293 µm is formed. The quasi-static compressive strength of GS Ti64 is higher than that of CG Ti64. Both CG Ti64 and GS Ti64 exhibit weak strain hardening effects and strain rate insensitivity during dynamic compression, and the compressive strength is not significantly improved. The lateral expansion of CG Ti64 is more obvious, while the lateral side of GS Ti64 is relatively straight, indicating that uniform deformation occurs in GS Ti64. The α phase in the GS produces dislocation cells and local deformation bands, and the lamellar structure is transformed into ultrafine crystals after dynamic compression. Both of them produce an adiabatic shear band under 2700 s−1, a large crack forms in CG Ti64, while GS Ti64 forms a small crack, indicating that GS Ti64 has better resistance to damage. The synergistic deformation of GS and CG promotes Ti-6Al-4V to obtain good dynamic mechanical properties.

scholarly journals Research on the Dynamic Mechanical Properties and Constitutive Models of Steel Fiber Reinforced Concrete and Polypropylene Fiber Reinforced Concrete

2020 ◽  
Vol 2020 ◽  
pp. 1-17 ◽  
Author(s):  
Jie Huang ◽  
Yi Zhang ◽  
Yubin Tian ◽  
Hengheng Xiao ◽  
Jun Shi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Steel Fiber ◽  
Polypropylene Fiber ◽  
Dynamic Mechanical Properties ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Dynamic Mechanical ◽  
Polypropylene Fiber Reinforced Concrete

This paper presents the results of an experimental research designed to investigate the dynamic mechanical properties and constitutive model of fiber reinforced concrete (FRC), including steel fiber reinforced concrete (SFRC) and polypropylene fiber reinforced concrete (PFRC) under fast loading. Experimental results are achieved by using the electrohydraulic servo loading test method, implying that the dynamic mechanical properties of PFRC and SFRC, such as peak stress, peak strain, and toughness, are positively affected by strain rate. The experimental elastic modulus test results of FRC with different fiber contents indicate that the elastic modulus is positively affected by polypropylene or steel fibers and increases with the increment of fiber content. Finally, the experimental stress-strain curves obtained in the MTS electrohydraulic servo system test are fitted by a damage dynamic constitutive model of FRC. The good fitting with experimental results proves that the model could be appropriate to describe the dynamic mechanical properties of FRC.

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