Properties of steel fiber self-compacting concrete incorporating quarry dust fine powder

2020 ◽  
Vol 11 (1) ◽  
pp. 1
Author(s):  
Joseph Abah Apeh ◽  
Juliet Eyum Ameh

Self-compacting concrete (SCC) has great potentials as it offers several environmental, economic and technical benefits. Moreover, the use of fibers extends its possibilities since fibers arrest cracks and retard their propagation. Incorporation of Quarry Dust (QD) in SCC help to reduce environmental hazards during the production of QD. This study evaluated the fresh and hardened properties of steel fiber self-compacting concrete (SFSCC) incorporating QD. The optimum fiber and QD contents with no adverse effects on fresh and hardened properties were determined. A comparative study on behavior of SCC and SFSCC mixtures in terms of workability, compressive strength, compressive strength development ratio, tensile, flexural and energy absorption capacity was carried out. Test results showed that compressive strength increased with increase in QD contents at fixed fiber content by mass of Portland cement (PC) and then decreased. Strength development ratio (C28/C7) for SCC was 1.13, while it was 1.06, 1.08, 1.10 and 1.01 after reinforcing with 0.10, 0.20 and 0.30 contents of fiber. The compressive, tensile, flexural and energy absorption capacity or Toughness of SFSCC increased with the inclusion of the aforementioned contents of steel fiber up to 0.20 % volume of total binder at constant QD content and then decreased when compared with control SCC values. From these results, optimum value for the variables studied was obtained from mix QD20 + 0.2fr. Hence, steel fiber and QD could be successfully used in SCC production not minding the slight draw back on workability of SCC caused by inclusion of steel fiber, but with a modified dosage of super-plasticizer (SP), fresh and hardened properties, in accordance with specifications in relevant code(s) can be achieved.

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 249
Author(s):  
Przemysław Rumianek ◽  
Tomasz Dobosz ◽  
Radosław Nowak ◽  
Piotr Dziewit ◽  
Andrzej Aromiński

Closed-cell expanded polypropylene (EPP) foam is commonly used in car bumpers for the purpose of absorbing energy impacts. Characterization of the foam’s mechanical properties at varying strain rates is essential for selecting the proper material used as a protective structure in dynamic loading application. The aim of the study was to investigate the influence of loading strain rate, material density, and microstructure on compressive strength and energy absorption capacity for closed-cell polymeric foams. We performed quasi-static compressive strength tests with strain rates in the range of 0.2 to 25 mm/s, using a hydraulically controlled material testing system (MTS) for different foam densities in the range 20 g/dm3 to 220 g/dm3. The above tests were carried out as numerical simulation using ABAQUS software. The verification of the properties was carried out on the basis of experimental tests and simulations performed using the finite element method. The method of modelling the structure of the tested sample has an impact on the stress values. Experimental tests were performed for various loads and at various initial temperatures of the tested sample. We found that increasing both the strain rate of loading and foam density raised the compressive strength and energy absorption capacity. Increasing the ambient and tested sample temperature caused a decrease in compressive strength and energy absorption capacity. For the same foam density, differences in foam microstructures were causing differences in strength and energy absorption capacity when testing at the same loading strain rate. To sum up, tuning the microstructure of foams could be used to acquire desired global materials properties. Precise material description extends the possibility of using EPP foams in various applications.


2021 ◽  
Vol 889 ◽  
pp. 123-128
Author(s):  
Sheng Jun Liu ◽  
Zhi Qiang Dong ◽  
Ren Zhong Cao ◽  
Da Song ◽  
Jia An Liu ◽  
...  

In this study, the open-cell Mg-2Zn-0.4Y foams were prepared by infiltration casting method. The Ni/Mg hybrid foams were prepared by electroless Ni-P coating on the foam struts to improve the compressive strength and energy absorption capacity. The compressive properties of the Mg alloy foams and Ni/Mg hybrid foams were studied by quasi-static compressive test. The experimental results show that the Ni-P coating is composed of crystallites. The Ni-P coating can significantly enhance the compressive strength, energy absorption capacity and energy absorption efficiency of the foams.


2020 ◽  
Vol 20 (1) ◽  
pp. 319-325
Author(s):  
Min-Jae Kim ◽  
Hong-Joon Choi ◽  
Booki Chun ◽  
Wonsik Shin ◽  
Doo-Yeol Yoo

This study aims to enhance the energy absorption capacity of cementitious composites with 2 vol.% of polyethylene fibers, by adjusting mixing ingredients and curing conditions. Ground blast furnace slag, cement kiln dust, limestone powder, and silica fume were incorporated, and two different curing conditions were applied: 72 h of curing at 90 ℃ and 120 h of curing at 40 ℃. Compressive strength test and direct tensile test were performed on 6 mixtures and the test results were compared with those of ultra-high-performance concrete and engineered cementitious composite specimens. The maximum compressive strength of the 6 mixtures was measured to be approximately 117 MPa. The higher cement replacement ratio of the other components resulted in a decrease in the compressive strength of the specimens cured at 90 ℃. In the direct tensile test, the specimens cured at 40 ℃ exhibited lower tensile strength than those cured at 90 ℃, but the strain capacity was increased by approximately 305% and reached 7.7%. This also resulted in an enhancement of the energy absorption capacity from 80%–292% because of the differences in micro-cracking and fracturing behaviors, such as an increase inthe number of micro-cracks and decrease in crack width.


2018 ◽  
Vol 22 (4) ◽  
pp. 948-961 ◽  
Author(s):  
Jinxiang Chen ◽  
Xindi Yu ◽  
Mengye Xu ◽  
Yoji Okabe ◽  
Xiaoming Zhang ◽  
...  

For the development of new types of lightweight sandwich structures, the compressive properties and strengthening mechanism of the middle-trabecular beetle elytron plate were investigated for various values of η (the ratio of the trabecular radius to the honeycomb wall length). The results are as follows: (1) When η = 0.1, the increases in the compressive strength and standard energy absorption capacity of the middle-trabecular beetle elytron plate compared with the honeycomb plate exceed those of the end-trabecular beetle elytron plate; with an increase to η = 0.15, the compressive strength remains nearly the same, the energy absorption capacity undergoes a significant further increase, and the trabeculae exhibit Φ-type failure. (2) The strengthening mechanism that gives rise to the compressive properties of the middle-trabecular beetle elytron plate is proposed as follows: the trabeculae are located at the center of the honeycomb walls, where the maximum deformations would otherwise occur; they constrain the deformation of the honeycomb walls; and the number of trabeculae in the middle-trabecular beetle elytron plate also exceeds that in the end-trabecular beetle elytron plate. (3) Middle-trabecular beetle elytron plates have the advantage of facile manufacturing, which will establish a basis for promoting the application of beetle elytron plates.


2020 ◽  
Vol 3 (1) ◽  
pp. 1-6
Author(s):  
J. M. Alavarado ◽  
A. Duarte

Nowadays there are several types of fiber for the reinforcement of the sprayed concrete used in tunnel support; most popular among them are steel fibers and macro synthetic fibers. However, in most cases the assessment of fiber reinforced sprayed concrete ductility is focused on the fulfillment of energy absorption capacity requirements without considering the effect of the reinforcement type on the Load-Displacement behavior. The following study aims to find out if the support capacity provided by each fiber type is the same for similar levels of energy absorption capacity or how it can be affected through the analysis of the load bearing capacity. After the analysis of energy absorption tests according to EFNARC of more than 50 specimens separately reinforced with steel and macro synthetic fibers, it was observed the specimens reinforced with steel fiber absorbed more energy since the beginning of deformation than those reinforced with macro synthetic fibers. In other words, the required work to start deforming the steel fiber reinforced sprayed concrete is greater than the required with the other fiber type. Likewise, the ultimate strength or maximum load bearing capacity provided by steel fibers was higher than the other fiber type. Therefore, the support capacity of the sprayed concrete and the related safety factor provided by each fiber type is different


2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Hai-long Li ◽  
Ying Xu ◽  
Pei-yuan Chen ◽  
Jin-jin Ge ◽  
Fan Wu

Adding rubber to concrete aims to solve the environmental pollution problem caused by waste rubber and to improve the energy absorption and impact resistance of concrete. In this paper, recycled rubber particles were used to replace fine aggregates in Portland cement concrete to combine the elasticity of rubber with the compression resistance of concrete. Fine aggregates in the concrete mixes were partially replaced with 0%, 20%, 40%, and 60% rubber by volume, and the cement in the concrete mixes was replaced with 0%, 5%, and 10% of silica fume by mass. The properties of the concrete specimens were examined through compressive strength, splitting tensile strength, flexural loading, and rebound tests. Results show that the compressive strength of concrete and the splitting tensile strength decreased to 11.81 and 1.31 MPa after adding silica fume to enhance the strength 37.8% and 23.7%, respectively, and the dosage of rubber was 60%. With the addition of rubber, the impact energy of rubberized concrete was 2.39 times higher than that of ordinary concrete, while its energy absorption capacity was 9.46% higher. The addition of silica fume increased its impact energy by 3.06 times, but the energy absorption capacity did not change significantly. In summary, the RC60SF10 can be used on non-load-bearing structures with high impact resistance requirements. A scanning electron microscope was used to examine and analyze the microstructural properties of rubberized concrete.


Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2544
Author(s):  
Tri N. M. Nguyen ◽  
Jung-J. Kim

The present study deals with tests on the energy absorption capacity and compressive strength of styrene–butadiene rubber (SBR) latex-modified cementitious materials. Different polymer–cement ratios (P/C) of 0, 5, 10, 15, and 20% were carried out with the Charpy impact test at 7, 14, and 28 days of curing. The observations showed an increase in the energy absorption capacity of the SBR latex-modified cement paste in correspondence with the increase in curing times, as well as the increase in the P/C ratios. The P/C ratio of 10% was the optimal ratio for observing the highest energy absorption capacity of the SBR latex-modified cement paste, with a 43% increase observed. In addition, a linear relationship between compressive strength and the energy absorption capacity at 28 days was proposed. Based on that, the energy absorption capacity of SBR latex-modified cement paste can be analyzed or predicted by the compressive strength results, regardless of the P/C ratios. Finally, the two-parameter Weibull distribution was proved to fit by the observation data from the Charpy impact test.


Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4435
Author(s):  
Gideon A. Lyngdoh ◽  
Sami Doner ◽  
Sumeru Nayak ◽  
Sumanta Das

This paper investigates the dynamic compressive behavior of wollastonite fiber-reinforced cementitious mortars using multiscale numerical simulations. The rate dependent behavior of the multiphase heterogeneous systems is captured in a multiscale framework that implements continuum damage towards effective property prediction. The influence of wollastonite fiber content (% by mass) as cement replacement on the dynamic compressive strength and energy absorption capacity is thereafter elucidated. An average compressive strength gain of 40% is obtained for mortars with 10% wollastonite fiber content as cement replacement, as compared to the control mortar at a strain rate of 200/s. The rate dependent constitutive responses enable the computation of energy absorption, which serves as a comparative measure for elucidating the material resistance to impact loads. Approximately a 45% increase in the dynamic energy absorption capacity is observed for the mixture containing 10% wollastonite fibers, as compared to the control case. Overall, the study establishes wollastonite fibers as a sustainable and dynamic performance-enhanced alternative for partial cement replacement. Moreover, the multiscale numerical simulation approach for performance prediction can provide an efficient means for the materials designers and engineers to optimize the size and dosage of wollastonite fibers for desired mechanical performance under dynamic loading conditions.


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