scholarly journals Exploring Environmentally Friendly Biopolymer Material Effect on Soil Tensile and Compressive Behavior

2020 ◽  
Vol 17 (23) ◽  
pp. 9032
Author(s):  
Chunhui Chen ◽  
Zesen Peng ◽  
JiaYu Gu ◽  
Yaxiong Peng ◽  
Xiaoyang Huang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Tensile Strength ◽  
High Performance ◽  
Xanthan Gum ◽  
Strengthening Effect ◽  
Bond Parameter ◽  
Underlying Mechanisms ◽  
Direct Tensile ◽  
Direct Tensile Test ◽  
The Impact

The study of the high-performance of biopolymers and current eco-friendly have recently emerged. However, the micro-behavior and underlying mechanisms during the test are still unclear. In this study, we conducted experimental and numerical tests in parallel to investigate the impact of different xanthan gum biopolymer contents sand. Then, a numerical simulation of the direct tensile test under different tensile positions was carried out. The micro-characteristics of the biopolymer-treated sand were captured and analyzed by numerical simulations. The results indicate that the biopolymer can substantially increase the uniaxial compressive strength and tensile strength of the soil. The analysis of the microparameters demonstrates the increase in the contact bond parameter values with different biopolymer contents, and stronger bonding strength is provided with a higher biopolymer content from the microscale. The contact force and crack development during the test were visualized in the paper. In addition, a regression model for predicting the direct tensile strength under different tensile positions was established. The numerical simulation results explained the mechanical and fracture behavior of xanthan gum biopolymer stabilized sand under uniaxial compression, which provides a better understanding of the biopolymer strengthening effect.

Behaviour of Different Types of Concrete under Impact and Quasi-Static Loading

2013 ◽  
Vol 486 ◽  
pp. 295-300 ◽  
Author(s):  
Petr Máca ◽  
Petr Konvalinka ◽  
Manfred Curbach
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Impact Loading ◽  
High Performance ◽  
High Performance Concrete ◽  
Fibre Reinforced Concrete ◽  
Static Conditions ◽  
Direct Tensile ◽  
Direct Tensile Strength ◽  
The Impact

This paper describes mixture formulation of Ultra High Performance Fibre Reinforced Concrete (UHPFRC) with 2% of fibres by volume and its response to quasi-static and dynamic impact loading. The UHPFRC mixture was prepared using locally available constituents and no special curing or mixing methods were used for its production. In addition, the mechanical parameters of three other types of concrete, i.e. normal strength concrete (NSC), fibre reinforced concrete (FRC) and high performance concrete (HPC) is compared. The main properties assessed throughout the experimental work are compressive, flexural and direct tensile strength as well as response of tested concretes to impact flexural loading. The impact loading is produced by a vertically falling weight of 24 kg from the height of 1 m on concrete prisms. The strain rate increase corresponds to low-velocity impacts such as vehicle crash or falling rocks. Compressive strength of UHPFRC exceeded 130 MPa and its direct tensile strength was 10.3 MPa. This type of concrete also exhibited strain hardening both in flexure under quasi-static conditions and during impact. Based on the comparison of impact reactions, it was concluded that the resistance of UHPFRC to impact loading is superior compared to the referent types of concretes (NSC, FRC, HPC).

Comparison of Tensile Strengths with Different Test Methods in Ultra High Strength Steel-Fiber Reinforced Concrete (UHS-SFRC)

2009 ◽  
Vol 417-418 ◽  
pp. 649-652 ◽  
Author(s):  
Su Tae Kang ◽  
Jung Jun Park ◽  
Gum Sung Ryu ◽  
Gyung Taek Koh ◽  
Sung Wook Kim
Keyword(s):  
Tensile Strength ◽  
Tensile Test ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Steel Fiber Reinforced Concrete ◽  
Flexural Tensile Strength ◽  
Ultra High Strength Steel ◽  
Direct Tensile ◽  
Direct Tensile Test ◽  
Direct Tensile Strength

Ultra High Strength Steel-Fiber Reinforced Concrete (UHS-SFRC) is characterized by very high compressive and tensile strength that is about 8 times of ordinary concrete, and high ductility owing to the addition of steel fibers. This paper investigates the relationship existing among the direct tensile strength, flexural tensile strength and splitting tensile strength of UHS-SFRC. Differently from ordinary concrete, it is found that the first cracking strengths in UHS-SFRC obtained through direct tensile test and splitting tensile test are similar, while the strength obtained from flexural tensile test is significantly larger than those from other tests. Based on the experimental results, relationships between the direct tensile strength and flexural tensile strength, between the first cracking strengths in direct tensile test and in flexural tensile test, and between the first cracking strength in direct tensile test and the flexural tensile strength are proposed.

Experimental investigation of recycled aggregate effect on the concrete properties

2018 ◽  
Vol 9 (4) ◽  
pp. 560-571
Author(s):  
Hamed Hemmati Pourghashti ◽  
Malek Mohammad Ranjbar ◽  
Rahmat Madandoust
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Tensile Test ◽  
Recycled Concrete ◽  
Test Results ◽  
Content Type ◽  
Treatment Conditions ◽  
Natural Aggregates ◽  
Direct Tensile ◽  
Direct Tensile Test

Purpose The purpose of this paper is to conduct a laboratory investigation on measuring the tensile strength of recycled concrete using a double punch test. Furthermore, one of the main goals of this study is to compare the tensile and compressive strengths of recycled concrete samples. Design/methodology/approach Recycled concrete samples were made with variables such as aggregate type (natural stone and aggregate recycled concrete), different water-to-cement ratios and different treatment conditions in the first stage. In the next stage, the double punch test was performed on them, and finally the results obtained from experiments were analyzed and investigated. Findings According to the above tests, it was concluded that: first, according to the laboratory results, the strength of concrete containing recycled aggregates becomes closer to the strength of concrete containing natural aggregates whenever the water-to-cement ratio is higher. Second, upon investigating the treatment conditions, it was observed that the treatment had a greater effect on the strength of the recycled concrete. However, this effect was less tangible in tensile strength. Third, upon investigating the results of tensile strength, it can be said that the Barcelona test results were closer to the direct tensile test results compared to the Brazilian test results. This indicates the higher viability of Barcelona’s test results. Fourth, the results obtained from the Barcelona tensile test for recycled concrete were closer to the results of the direct tensile test compared to the concrete containing natural aggregates, which suggests that the Barcelona test is more suitable as a tensile test for recycled concrete. Fifth, the effects of various factors on tensile strength were somewhat less compared to the compressive strength, although very close. Sixth, the relationships provided by the regulation for concrete tensile strength on compressive strength were highly inconsistent with the results obtained from the direct tensile test, for which the consistency was higher for concrete containing natural aggregates compared to recycled concrete. Seventh, the dispersion of results obtained from tensile tests was higher for recycled concrete compared to concrete containing natural aggregates, but lesser of this dispersion was observed in the compressive strength. Originality/value According to the laboratory results, the strength of concrete containing recycled aggregates becomes closer to the strength of concrete containing natural aggregates whenever the water-to-cement ratio is higher. Upon investigating the treatment conditions, it was observed that the treatment had a greater effect on the strength of the recycled concrete. However, this effect was less tangible in tensile strength. On the basis on the results of the tensile strength, it can be said that the Barcelona test results were closer to the results of the direct tensile test compared to those of the Brazilian test. This indicates the higher viability of Barcelona’s test results. The results obtained from the Barcelona tensile test for recycled concrete were closer to the results of direct tensile test compared to the concrete containing natural aggregates, which suggests that the Barcelona test is more suitable as a tensile test for recycled concrete. The effects of various factors on tensile strength were somewhat less compared to the compressive strength, although very close. The relationships provided by the regulation for concrete tensile strength on compressive strength were highly inconsistent with the results obtained from the direct tensile test, for which the consistency was higher for concrete containing natural aggregate compared to recycled concrete. The dispersion of results obtained from tensile tests was higher for recycled concrete compared to concrete containing natural aggregate, but lesser of this dispersion was observed in the compressive strength.

scholarly journals Synchronously Strengthen and Toughen Polypropylene Using Tartaric Acid-Modified Nano-CaCO3

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2493
Author(s):  
Junlong Yao ◽  
Hanchao Hu ◽  
Zhengguang Sun ◽  
Yucong Wang ◽  
Huabo Huang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Impact Toughness ◽  
Tartaric Acid ◽  
High Performance ◽  
Mechanical Performance ◽  
Low Cost ◽  
Complexing Agent ◽  
Environmental Technology ◽  
The Impact ◽  
First Time

In order to overcome the challenge of synchronously strengthening and toughening polypropylene (PP) with a low-cost and environmental technology, CaCO3 (CC) nanoparticles are modified by tartaric acid (TA), a kind of food-grade complexing agent, and used as nanofillers for the first time. The evaluation of mechanical performance showed that, with 20 wt.% TA-modified CC (TAMCC), the impact toughness and tensile strength of TAMCC/PP were 120% and 14% more than those of neat PP, respectively. Even with 50 wt.% TAMCC, the impact toughness and tensile strength of TAMCC/PP were still superior to those of neat PP, which is attributable to the improved compatibility and dispersion of TAMCC in a PP matrix, and the better fluidity of TAMCC/PP nanocomposite. The strengthening and toughening mechanism of TAMCC for PP involves interfacial debonding between nanofillers and PP, and the decreased crystallinity of PP, but without the formation of β-PP. This article presents a new applicable method to modify CC inorganic fillers with a green modifier and promote their dispersion in PP. The obtained PP nanocomposite simultaneously achieved enhanced mechanical strength and impact toughness even with high content of nanofillers, highlighting bright perspective in high-performance, economical, and eco-friendly polymer-inorganic nanocomposites.

scholarly journals Numerical Investigation on Dynamic Response of RC T-Beams Strengthened with CFRP under Impact Loading

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 890
Author(s):  
Huiling Zhao ◽  
Xiangqing Kong ◽  
Ying Fu ◽  
Yihan Gu ◽  
Xuezhi Wang
Keyword(s):  
Numerical Simulation ◽  
Impact Force ◽  
Reaction Force ◽  
Impact Resistance ◽  
Structural Response ◽  
Element Model ◽  
Strengthening Effect ◽  
Strengthened Beam ◽  
Simulation Results ◽  
The Impact

To precisely evaluate the retrofitting effectiveness of Carbon Fiber Reinforced Plastic (CFRP) sheets on the impact response of reinforced concrete (RC) T-beams, a non-linear finite element model was developed to simulate the structural response of T-beams with CFRP under impact loads. The numerical model was firstly verified by comparing the numerical simulation results with the experimental data, i.e., impact force, reaction force, and mid-span displacement. The strengthening effect of CFRP was analyzed from the section damage evaluation. Then the impact force, mid-span displacement, and failure mode of CFRP-strengthened RC T-beams were studied in comparison with those of un-strengthened T-beams. In addition, the influence of the impact resistance of T-beams strengthened with FRP was investigated in terms of CFRP strengthening mode, CFRP strengthening sizes, CFRP layers and FRP material types. The numerical simulation results indicate that the overall stiffness of the T-beams was improved significantly due to external CFRP strips. Compared with the un-strengthened beam, the maximum mid-span displacement of the CFRP-strengthened beam was reduced by 7.9%. Additionally, the sectional damage factors of the whole span of the CFRP-strengthened beam were reduced to less than 0.3, indicating that the impact resistance of the T-beams was effectively enhanced.

Interface Shear Strength of Carbon Fiber Mesh (CFM) Attached to RC Surface for External Reinforcing

2006 ◽  
Vol 324-325 ◽  
pp. 799-802
Author(s):  
Soo Yeon Seo ◽  
Hyun Do Yun ◽  
Chang Sik Choi ◽  
Ki Bong Choi
Keyword(s):  
Carbon Fiber ◽  
Bond Strength ◽  
Drying Shrinkage ◽  
Strengthening Effect ◽  
Interface Shear ◽  
Existing Structures ◽  
Externally Bonded ◽  
Direct Tensile ◽  
Direct Tensile Test ◽  
Fiber Mesh

The strengthening of concrete structures in situ with externally bonded carbon fiber is increasingly being used for repair and rehabilitation of existing structures since carbon fiber has good mechanical properties such as high tensile strength, good resistances to corrosion, and low self-weight, which are attractive for retrofitting of RC member. In using Carbon Fiber Mesh (CFM) as a retrofit material for RC member, most important structural property that should be developed is the bond strength between RC member and CFM. The additional strength increment by CFM can be developed if the bond strength is sufficient. If it is not, the strengthening effect can not be expected due to the bond failure between concrete and CFM. A direct tensile test was performed in order to find the variation of bond strength and load-displacement response of CFM attached to the concrete and the result is presented in this paper. The key parameters of the test are the location of clip for the installation of CFM, number of clips and thickness of cover mortar. Test results indicate that the bond strength is dependent on the number of clips and maximized at clip numbers of three per each rod. In specimens without clips, the highest strength was found in the specimen with cove mortar of 30mm and lowest one in specimen with largest mortar thickness. This means that in too much thick of cover mortar, it seems that the amount of drying shrinkage is increased and this reduces rather than improves the bond strength.

Influence of Hybrid Steel Fiber Addition on Direct Tensile Behavior of UHPC

2016 ◽  
Vol 713 ◽  
pp. 270-272
Author(s):  
Seung Hun Park ◽  
Kyung Taek Koh ◽  
Gum Sung Ryu ◽  
Gi Hong An ◽  
Nam Kon Lee
Keyword(s):  
High Performance ◽  
Steel Fiber ◽  
Absorption Capacity ◽  
Tensile Behavior ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Energy Absorption Capacity ◽  
High Performance Fiber ◽  
Direct Tensile ◽  
Direct Tensile Test

This paper examines the direct tensile behavior of ultra high performance fiber reinforced concrete (UHPFRC) according to the addition of hybrid-type steel fibers with different lengths and diameters but identical aspect ratio. Two types of steel fibers that are MS fiber with length of 20 mm and diameter of 0.2 mm and LS fiber with length of 22 mm and diameter of 0.22 mm are adopted and admixed together with different proportions to give three series of mixes (MS10LS05, MS075LS075, MS05LS10). Direct tensile test is conducted on specimens using each of the considered mixes and notched on both sides. The results show that the tensile strength and the energy absorption capacity of UHPFRC tend to increase with larger proportions of relatively long steel fibers.

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