Properties of Cracking Resistance of Cemfiber Reinforced Concrete

2007 ◽  
Vol 280-283 ◽  
pp. 1765-1770 ◽  
Author(s):  
Feng Xing ◽  
Fa Guang Leng ◽  
Wei Wen Li
Keyword(s):  
Tensile Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Polypropylene Fiber ◽  
Shrinkage Strain ◽  
Early Age ◽  
Polypropylene Fibers ◽  
Cracking Resistance ◽  
Ordinary Concrete ◽  
Concrete Form

Polypropylene fiber is a new measure to prevent plastic cracks of concrete. Effects of the parameters, such as dosage and types of fibers, on the plastic cracks were studied systematically. The properties of cracking resistance of mortar, ordinary concrete and high performance concrete were investigated by using samples of two types in shape. The results show that: (1) polypropylene fibers may increase the cracking resistance of concrete further; (2) as smaller quantity of cement and higher quantity of aggregate as possible should be used to prevent concrete form cracking; (3) the main reason why polypropylene fibers increase cracking resistance of concrete is that they increase strain capacity of concrete at early age, decrease shrinkage strain, improve plastic tensile strength and decrease tensile stress of the capillary.

scholarly journals Characteristics of Recycled Polypropylene Fibers as an Addition to Concrete Fabrication Based on Portland Cement

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1827 ◽  
Author(s):  
Marcin Małek ◽  
Mateusz Jackowski ◽  
Waldemar Łasica ◽  
Marta Kadela
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Polypropylene Fiber ◽  
Fiber Reinforced Concrete ◽  
Polypropylene Fibers ◽  
Split Tensile Strength ◽  
Recycled Polypropylene ◽  
Recycled Fibers

High-performance concrete has low tensile strength and brittle failure. In order to improve these properties of unreinforced concrete, the effects of adding recycled polypropylene fibers on the mechanical properties of concrete were investigated. The polypropylene fibers used were made from recycled plastic packaging for environmental reasons (long degradation time). The compressive, flexural and split tensile strengths after 1, 7, 14 and 28 days were tested. Moreover, the initial and final binding times were determined. This experimental work has included three different contents (0.5, 1.0 and 1.5 wt.% of cement) for two types of recycled polypropylene fibers. The addition of fibers improves the properties of concrete. The highest values of mechanical properties were obtained for concrete with 1.0% of polypropylene fibers for each type of fiber. The obtained effect of an increase in mechanical properties with the addition of recycled fibers compared to unreinforced concrete is unexpected and unparalleled for polypropylene fiber-reinforced concrete (69.7% and 39.4% increase in compressive strength for green polypropylene fiber (PPG) and white polypropylene fiber (PPW) respectively, 276.0% and 162.4% increase in flexural strength for PPG and PPW respectively, and 269.4% and 254.2% increase in split tensile strength for PPG and PPW respectively).

Effect of the Expansion Agent on Early-Age Autogenous Shrinkage Stress of Concrete

2013 ◽  
Vol 838-841 ◽  
pp. 564-568
Author(s):  
Pan Xiu Wang
Keyword(s):  
Tensile Strength ◽  
Concrete Structure ◽  
High Performance ◽  
High Performance Concrete ◽  
Autogenous Shrinkage ◽  
Shrinkage Strain ◽  
Shrinkage Stress ◽  
Early Age ◽  
Concrete Cube

Early-age autogenous shrinkage is key problem of high performance concrete. It can cause a lot of early-age cracks in concrete structure and further endanger the permeability and durability. Adding expansion agent can control the early-age autogenous shrinkage strain and reduce the risk of early-age cracks. In this paper, the early-age autogenous shrinkage stress of concrete cube is calculated. The results show that, early-age autogenous shrinkage stress is larger than early-age tensile strength of concrete. So some cracks occur on the surface of concrete structure. By adding expansion agent, the early-age autogenous shrinkage strain and stress both decreases.

Mechanics Performance of High-Performance Concrete with Polypropylene Fibers

2011 ◽  
Vol 99-100 ◽  
pp. 1233-1238
Author(s):  
Hong Xiu Du ◽  
Yi Xiao Qin ◽  
Wei Zhang ◽  
Ning Zhang ◽  
Xiao Yu Hao
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Beneficial Effect ◽  
High Performance ◽  
High Performance Concrete ◽  
Polypropylene Fiber ◽  
Polypropylene Fibers ◽  
Micro Cracks ◽  
Mechanics Performance ◽  
Stress And Deformation

The mechanics properties of HPC mixing different dosage and length of polypropylene fiber were investigated in this study. The results showed that the addition of appropriate amount and length of polypropylene fibers in HPC led to an effective improvement in the tensile strength and a little change in the compressive strength of HPC. The pronounced improvement can be attributed to the beneficial effect of polypropylene fiber on HPC by restraining the generation and development of the micro cracks in concrete, enhancing the level of stress and deformation and damage characteristics in HPC, furthermore, extending the durability and safety of concrete structure.

Research on Self-Desiccation at early Age of High Performance Concrete with Polypropylene Fiber

2011 ◽  
Vol 374-377 ◽  
pp. 1827-1830
Author(s):  
Wei Wei Yu ◽  
Qing Xiong ◽  
Yun Yu ◽  
Hang Lin
Keyword(s):  
Relative Humidity ◽  
High Performance ◽  
High Performance Concrete ◽  
Polypropylene Fiber ◽  
The Self ◽  
Experimental Results ◽  
Early Age ◽  
Experimental Conditions ◽  
Internal Relative Humidity ◽  
The Impact

This paper focuses on the impact which polypropylene fiber (PF) has on the self-desiccation effect at early age of high performance concrete (HPC). The experimental results indicate that PF has little influence on the Internal Relative Humidity (IRH) caused by self-desiccation effect of concrete, but can reduce early aged self-desiccation shrinkage of concrete. With the PF dosage increasing, the values of early self-desiccation shrinkage of HPC decrease first and then increase. In the experimental conditions, the value of self-desiccation shrinkage of concrete with 0.6Kg/m3 PF is the lowest one.

Flexural Toughness of Hybrid Fiber Reinforced High-Performance Concrete under Three-Point Bending

2013 ◽  
Vol 357-360 ◽  
pp. 1110-1114
Author(s):  
Dong Tao Xia ◽  
Xiang Kun Liu ◽  
Bo Ru Zhou
Keyword(s):  
Tensile Strength ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Volume Fraction ◽  
Polypropylene Fiber ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Fiber Volume ◽  
Flexural Toughness

A set of new hybrid fiber reinforced high-performance concrete was developed and studied by experiment. The fibers incorporated the concrete are the collection of the steel fiber, modified polypropylene fiber and polypropylene with total fiber content not more than 1%. And the compressive test, splitting tensile test and the flexural toughness test were performed on eight groups of specimens. Based on the load-deflection and load-CMOD curves and the equivalent flexural tensile strength, the effect of fiber volume fraction and hybrid mode upon concrete's mechanical properties and post-peak behavior were investigated. The test results show that the mixing of the three different fibers can increase concrete's splitting tensile strength and flexural toughness more effectively with no significantly effect on compressive strength. The mixture of the three different fibers exist the optimization problem. Based on the results of the analysis, the compatible proportion of the three fibers is 0.7% steel fiber, 0.19% modified polypropylene fiber and 0.11% polypropylene fiber.

To the Problem of Assessing the Level of Self- Stresses during the Formation of the Structure of Self-Compacting Concrete

2019 ◽  
Vol 974 ◽  
pp. 293-298
Author(s):  
G.V. Nesvetaev ◽  
Y.I. Koryanova ◽  
T.N. Zhilnikova ◽  
A.V. Kolleganov
Keyword(s):  
Tensile Strength ◽  
Crack Resistance ◽  
Shrinkage Strain ◽  
Cement Stone ◽  
Self Compacting Concrete ◽  
Cracking Resistance ◽  
Shrinkage Crack ◽  
Ordinary Concrete ◽  
Creep Coefficient ◽  
Mineral Additives

Conditional quantitative criteria characterizing the shrinkage crack resistance of various concretes and a model describing the change in the proposed criteria depending on the magnitude of shrinkage deformation, creep coefficient, tensile strength kinetics and shrinkage strain kinetics for ordinary concrete and self-compacting concrete are proposed. The proposed criteria for the class C40/50 concrete have been calculated and it was shown that self-compacting concrete can potentially have higher crack resistance during shrinkage. To ensure high cracking resistance during shrinkage when choosing superplasticizers and mineral additives, attention should be paid to their effect on shrinkage, creep and E-modulus of the cement stone. It should exclude additives that increase the shrinkage and E-modulus and reduce creep of cement stone.

Effect of polypropylene plastic fibers length on cracking resistance of high performance concrete at early age

2020 ◽  
Vol 244 ◽  
pp. 117874 ◽  
Author(s):  
Dejian Shen ◽  
Xingzuo Liu ◽  
Xuan Zeng ◽  
Xiaoguang Zhao ◽  
Guoqing Jiang
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Early Age ◽  
Cracking Resistance

Temperature Control and Crack Prevention of High-Performance Concrete Pier in San Yang Gang Tide Gate

2012 ◽  
Vol 573-574 ◽  
pp. 1203-1210
Author(s):  
Zhong Yang
Keyword(s):  
Temperature Control ◽  
High Performance ◽  
High Performance Concrete ◽  
Polypropylene Fiber ◽  
Three Dimensional ◽  
Cooling Water ◽  
Early Age ◽  
Sluice Gate ◽  
Tide Gate ◽  
Temperature Crack

San Yang Gang tidal sluice gate is easily to produce temperature crack at early age because of the use of pump hydrotechnic high performance concrete in the constructing process. Based on the analysis of parameters of three-dimensional temperature field and temperature stress field, comprehensive measures which are consist of lower inside temperature through cooling water pipes , keep the outer surface moist, increase temperature distribution bars, reduce pumping concrete slump and mixing polypropylene fiber were proposed. These comprehensive measures have solved the problem of temperature control and crack prevention successfully.

scholarly journals Influence of Rapid Heat Treatment on the Shrinkage and Strength of High-Performance Concrete

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4102
Author(s):  
Jan Stindt ◽  
Patrick Forman ◽  
Peter Mark
Keyword(s):  
Heat Treatment ◽  
High Performance ◽  
High Performance Concrete ◽  
Treatment Time ◽  
Precast Concrete ◽  
Concrete Strength ◽  
Shrinkage Strain ◽  
Temperature Treatment ◽  
Production Flow ◽  
Steel Fibres

Resource-efficient precast concrete elements can be produced using high-performance concrete (HPC). A heat treatment accelerates hardening and thus enables early stripping. To minimise damages to the concrete structure, treatment time and temperature are regulated. This leads to temperature treatment times of more than 24 h, what seems too long for quick serial production (flow production) of HPC. To overcome this shortcoming and to accelerate production speed, the heat treatment is started here immediately after concreting. This in turn influences the shrinkage behaviour and the concrete strength. Therefore, shrinkage is investigated on prisms made from HPC with and without steel fibres, as well as on short beams with reinforcement ratios of 1.8% and 3.1%. Furthermore, the flexural and compressive strengths of the prisms are measured directly after heating and later on after 28 d. The specimens are heat-treated between 1 and 24 h at 80 °C and a relative humidity of 60%. Specimens without heating serve for reference. The results show that the shrinkage strain is pronouncedly reduced with increasing temperature duration and rebar ratio. Moreover, the compressive and flexural strength decrease with decreasing temperature duration, whereby the loss of strength can be compensated by adding steel fibres.

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