CN202055393U

CN202055393U - High-strength reinforcement high-ductility fiber reinforced engineered cementitious composite compressed member

Info

Publication number: CN202055393U
Application number: CN2011200268869U
Authority: CN
Inventors: 邓宗才; 薛会青
Original assignee: Beijing University of Technology
Current assignee: Beijing University of Technology
Priority date: 2011-01-26
Filing date: 2011-01-26
Publication date: 2011-11-30
Anticipated expiration: 2021-01-26

Abstract

The utility model belongs to the field of building structures, in particular to a high-strength reinforcement high-ductility fiber reinforced ECC (engineered cementitious composite) compressed member, which is formed by cast ECCs and internally comprises a steel bar cage made of longitudinal compressed bars and ties. The compressed member is made of the ECCs instead of common concrete. Longitudinal compressed bars are high-strength reinforcement, so that the problem that the reinforced concrete structure prematurely deteriorates due to cracking and even fails to service is solved, performance advantages of the ECCs and the high-strength reinforcement are fully utilized, and bearing capacity, rigidity, energy dissipation capacity and ductility of column members are improved.

Description

High tensile reinforcement strengthens high-tenacity fiber refinforced cement based composites compressed member

Technical field

The utility model belongs to building structure field, is specifically related to a kind of compressed member that utilizes high tensile reinforcement and high-tenacity fiber refinforced cement based composites (Engineered Cementitious Composite is called for short ECC) preparation.

Background technology

The reinforced concrete structure performance degradation is caused by concrete deterioration and reinforcing bar deterioration, and the deterioration of this two aspect is all relevant with crack on concrete.Under extraneous load or environmental activity, crack on concrete has not only reduced the bearing capacity of structure, and quickened the speed that hazardous substancess such as water, carbon dioxide and chlorion are invaded to inside concrete, finally cause corrosion of steel bar, impel concrete structure deterioration prematurely, even completely lose function of use.Can effectively increase the bearing capacity of compressed member by the toughness of the cracking that reduces concrete structure, the growth that suppresses crack width and raising material.Some Important Project structures are also split, are limit and the aspect such as split, toughness reinforcing and have higher requirement resistance, and tensile strength is low, easy to crack, crack width is difficult to shortcomings such as control but concrete has.So need seek a kind of new structure system that can effectively limit crack generation and development.

Though fibrous concrete has been alleviated shortcomings such as concrete is easy to crack to a certain extent, directly under the tensile load effect strain softening breakoff phenomenon is taking place still.High-tenacity fiber refinforced cement based composites is based on a kind of cement-base composite material (being called for short ECC) that possesses strain hardening and many seam cracking properties of Micromechanics principle, has obtained a large amount of research and application in recent years.

The ECC material has the characteristics of strain hardening and many seam crackings, and high tensile reinforcement possesses advantages such as the high and ductility of intensity is good, and the compressed member that ECC and high tensile reinforcement combine can be given full play to the performance advantage of two kinds of materials.Therefore, high tensile reinforcement enhancing high-tenacity fiber refinforced cement based composites compressed member has important engineering application value.

The utility model content

The utility model provides a kind of high tensile reinforcement to strengthen the ECC compressed member, this member replaces the ordinary concrete material with the ECC material, the longitudinal stress muscle adopts high tensile reinforcement, overcome reinforced concrete structure because the premature deterioration that the crack produces, even the problem of forfeiture function of use, give full play to the performance advantage of ECC and high tensile reinforcement, improved post bearing of component, rigidity, energy dissipation capacity and ductility.

The utility model adopts following technical scheme:

A kind of high tensile reinforcement strengthens high-tenacity fiber refinforced cement based composites compressed member, and this compressed member is built by high-tenacity fiber refinforced cement based composites 2 and formed, and includes the reinforcing cage of being made by longitudinal stress muscle 1 and stirrup 3 at component inside.

Fiber in the high-tenacity fiber refinforced cement based composites 2 in the above-mentioned high tensile reinforcement enhancing high-tenacity fiber refinforced cement based composites compressed member adopts flexible short fiber.

The longitudinal stress muscle 1 that above-mentioned high tensile reinforcement strengthens in the high-tenacity fiber refinforced cement based composites compressed member can adopt high tensile reinforcement.

The cross section that above-mentioned high tensile reinforcement strengthens high-tenacity fiber refinforced cement based composites compressed member is rectangle or circle.

The concrete making step of above-mentioned high tensile reinforcement enhancing high-tenacity fiber refinforced cement based composites compressed member is as follows:

1) arrangement of reinforcement: be compiled into reinforcing cage by longitudinal stress muscle and stirrup, be fixed in the template of propping up and brushing good oil in advance, guarantee the correct position of reinforcing cage, no tilt phenomenon takes place.Described longitudinal stress muscle adopts high tensile reinforcement, and stirrup adopts plain bars, and template can adopt punching block, wooden model etc.

2) build: divide two-layer building after the ECC material stirs, at first build half, slightly vibrate 1-2min to guarantee the material vibration compacting with vibrating spear; Then with the same manner build residue half, at last that the surface is floating, and cover with plastic sheeting.

The performance of concrete and ECC material is as follows:

Material category	Crack initiation stretching strain/μ ε	Ultimate tensile strength/μ ε	Crack initiation compressive strain/μ ε	Limit compressive strain/μ ε
					Concrete	-	100～150	?-	2000
ECC	500～700	20000～30000	?1700～2300	5000～7000

The performance of high tensile reinforcement is as follows:

Material category	Yield strain/μ ε	Limiting strain/μ ε	Yield strength/MPa
				High tensile reinforcement	?2250～4000	?25000	450～800

High tensile reinforcement strengthens the ECC compressed member to be compared with the ordinary reinforced concrete compressed member, and performance is more superior, this be because:

The ordinary reinforced concrete compressed member is when compression damage, and reinforcing bar has reached its yield strength, the topping concrete spalling, and the vertical muscle between the stirrup is buckled and is outwards protruded, mid portion coagulation soil pressure shortcake, concrete stress reaches the compressive strength of cylinder.Concrete maximum compressive strain is 0.002, when vertical muscle adopts high tensile reinforcement, and the post component damage, the stress of reinforcing bar may not reach its yield strength, and the intensity of this explanation high tensile reinforcement is not fully utilized, therefore the improper concrete compression members that is used for.

By the constitutive relation of ECC material uniaxial compression and high tensile reinforcement, when the compressed member compressive strain reaches ECC crack initiation compressive strain ε _CcThe time, ECC material (ε _c=ε _Cc) crack initiation, but do not deactivate, but with the high tensile reinforcement (ε of surrender not also _Sy＞ε _Cc) continue together to carry; When the compressed member compressive strain reaches yield strain ε _SyThe time, high tensile reinforcement begins surrender, at this moment ECC material (ε _c＜ε _Cu) crack is thin and close, belongs to harmless crack, can give full play to the characteristic of high tensile reinforcement.As the compressed member compressive strain compressive strain ε that reaches capacity _CuThe time, ECC material (ε _c=ε _Cu) compressive strength that reaches capacity, can not continue carrying, member destroys.

The utlity model has following beneficial effect:

1) this compressed member makes full use of the good advantage of the high ductility of high tensile reinforcement intensity;

2) this compressed member makes full use of the characteristic of the sclerosis of ECC material strain and many seam crackings;

3) to compare performance more superior for this compressed member and ordinary reinforced concrete compressed member, can improve bearing capacity, rigidity, energy dissipation capacity and the ductility of compressed member.

Description of drawings

Fig. 1 is the uniaxial compression constitutive relation of ECC material;

Fig. 2 is the constitutive relation of high tensile reinforcement;

Fig. 3 strengthens ECC compressed member square-section figure for high tensile reinforcement;

Fig. 4 strengthens ECC compressed member circular cross-section figure for high tensile reinforcement;

Among the figure, the 1st, longitudinal stress muscle, the 2nd, ECC material, the 3rd, stirrup; σ _Cc, σ _CuBe respectively crack initiation compressive strength and ultimate compressive strength; ε _Cc, ε _CuBe respectively crack initiation compressive strain and limit compressive strain; σ _yBe the yield strength of reinforcing bar, ε _SyBe yield strain, ε _SuIt is the limiting strain of reinforcing bar.

The specific embodiment

Below in conjunction with specific embodiment the utility model is described further:

High tensile reinforcement enhancing ECC square-section compressed member and circular cross-section compressed member are made up of longitudinal stress muscle 1, ECC material 2 and stirrup 3 respectively as shown in Figure 3 and Figure 4.Adopt following steps to construct:

1) arrangement of reinforcement: be compiled into reinforcing cage by longitudinal stress muscle 1 and stirrup 3, be fixed in the steel form that props up and brush good oil in advance, guarantee the correct position of reinforcing cage, no tilt phenomenon takes place.Described longitudinal stress muscle 1 adopts high tensile reinforcement, and stirrup 3 adopts plain bars.

2) build: divide two-layer building after ECC material 2 stirs, at first build half, slightly vibrate 1-2min to guarantee the material vibration compacting with vibrating spear; Then with the same manner build residue half, at last that the surface is floating, and cover with plastic sheeting.

More than be an exemplary embodiments of the present utility model, enforcement of the present utility model is not limited thereto.

Claims

1. a high tensile reinforcement strengthens high-tenacity fiber refinforced cement based composites compressed member, it is characterized in that, this compressed member is built by high-tenacity fiber refinforced cement based composites (2) and is formed, and includes the reinforcing cage of being made by longitudinal stress muscle (1) and stirrup (3) at component inside.

2. a kind of high tensile reinforcement according to claim 1 strengthens high-tenacity fiber refinforced cement based composites compressed member, it is characterized in that the fiber in the high-tenacity fiber refinforced cement based composites (2) adopts flexible short fiber.

3. a kind of high tensile reinforcement according to claim 1 strengthens high-tenacity fiber refinforced cement based composites compressed member, it is characterized in that longitudinal stress muscle (1) adopts high tensile reinforcement.

4. a kind of high tensile reinforcement according to claim 1 strengthens high-tenacity fiber refinforced cement based composites compressed member, it is characterized in that the cross section of compressed member is rectangle or circle.