CN110776287A - Fiber self-compacting concrete and manufacturing method thereof - Google Patents

Abstract

The invention discloses a fiber self-compacting concrete, which comprises the following raw materials in unit volume: cement 330- ³Mineral admixture 140-144kg/m ³835-842.8kg/m of coarse aggregate ³790-797.6kg/m of fine aggregate ³0-8.4kg/m of basalt fiber ³34.3 to 44.8kg/m of additive ³178- ³. The basalt fiber is chopped basalt fiber or pretreated chopped basalt fiber. The invention discloses a preparation method of the fiber self-compacting concrete, which comprises the steps of uniformly mixing basalt fibers, fine aggregate and coarse aggregate, sequentially adding water and an additive, uniformly stirring, adding cement and a mineral admixture, and stirring. The concrete obtained by the invention not only has light weight, but also enhances the strength and toughness of each part of the concrete, and simultaneously can keep the heat resistance and corrosion resistance of basalt fibers.

Description

Fiber self-compacting concrete and manufacturing method thereof

Technical Field

The invention relates to the technical field of self-compacting concrete, in particular to fiber self-compacting concrete and a manufacturing method thereof.

Background

Compared with the traditional concrete, the fiber concrete can obviously improve the compressive strength and the splitting tensile strength of the concrete. But is not beneficial to the formation and development of early strength of concrete, and secondly, the addition of the fiber can reduce the slump of concrete and the fluidity of the concrete is deteriorated. At the parts with high reinforcement ratio or small structural section, the concrete vibrator is difficult to vibrate, and the fiber concrete with low fluidity is difficult to compact at the parts, so that honeycombs, pitted surfaces and the like are formed to influence the bearing capacity and durability of the concrete structure.

The self-compacting concrete does not need the vibration of vibration equipment, and can be filled and wrapped with the concrete of the reinforcing steel bars under the action of gravity. The concrete has high-temperature deformation resistance, low-temperature crack resistance and good anti-permeability performance, and the setting time can be freely adjusted according to the construction requirements.

The fiber self-compacting concrete has the advantages of the fiber concrete, and has wide application prospects in road and bridge engineering, building engineering, hydraulic engineering and the like. The fiber self-compacting concrete can overcome the defects of low strength and poor impermeability of the traditional concrete, has good fluidity, can be filled and compacted at the position with high reinforcement ratio and small section size, saves manual vibration and has obvious economic benefit.

Disclosure of Invention

The invention aims to solve the defects in the prior art, and provides fiber self-compacting concrete and a manufacturing method thereof.

The fiber self-compacting concrete comprises the following raw materials in unit volume: cement 330- ³Mineral admixture 140-144kg/m ³835-842.8kg/m of coarse aggregate ³790-797.6kg/m of fine aggregate ³0-8.4kg/m of basalt fiber ³34.3 to 44.8kg/m of additive ³178- ³。

Preferably, the basalt fibers are chopped basalt fibers.

Preferably, the chopped basalt fiber has the length of 5-24mm, the monofilament diameter of 10-15 mu m and the density of 2600-3000kg/m ³The tensile modulus is 100-110GPa, the tensile strength is 3800-4000MPa, and the elongation at break is 2.5-3.0%.

Preferably, the chopped basalt fiber has a maximum working temperature of 650 ℃ and an alkali resistance of 78-82% of a retention rate of a single-filament breaking strength.

Basalt fiber contains K ₂O、MgO、TiO ₂The components play an important role in improving the chemical corrosion resistance and the waterproof performance of the fiber.

Preferably, the cement is ordinary portland cement having a strength rating of 42.5, 52.5 and/or 62.5.

Preferably, the mineral admixture is fly ash having an apparent density of 2 to 3g/cm ³The specific surface area is 4500- ²/g。

Preferably, the fineness of the fly ash is 8-10%, the water demand ratio is 85-90%, and the loss on ignition is 4.0-4.5%.

Preferably, the additive is a water reducing agent, the water reducing rate of the additive is 25-30%, the bleeding rate is 18-22%, and the gas content is 3.5-4.0%.

Preferably, the coarse aggregate is graded crushed stone, and the grain composition of the coarse aggregate is 5-20 mm.

Preferably, the fine aggregate is continuous graded medium sand, and the fineness modulus of the fine aggregate is 2.5-3.0.

Preferably, the raw materials and the unit volume dosage thereof comprise: 332kg/m of cement ³Mineral blend 142kg/m ³838.9kg/m coarse aggregate ³793.8kg/m of fine aggregate ³0-8.4kg/m of basalt fiber ³34.3 to 44.8kg/m of additive ³180kg/m of water ³。

The preparation method of the fiber self-compacting concrete comprises the following steps:

s1, uniformly mixing the fine aggregate and the coarse aggregate to obtain a primary mixed material;

s2, slowly adding basalt fibers into the primary mixed material under the stirring state, then adding an additive, and uniformly stirring to obtain a secondary mixed material;

and S3, adding water into the secondary mixed material under the stirring state, uniformly stirring, and then adding cement and mineral admixture and stirring.

The invention has the advantages that: the novel basalt fiber is adopted as a fiber reinforced material, so that the mechanical property of the obtained concrete is improved, the mixing proportion of the concrete is optimized, the performance of the self-compacting concrete can be met by the obtained concrete, the advantages of the basalt fiber and the concrete are achieved, and the application prospect in civil engineering is wide. The basalt fiber is utilized to manufacture the concrete layer, the whole structure is reinforced, the durability is better than that of common self-compacting concrete, the basalt fiber is low in price compared with steel fiber, carbon fiber and the like, the cost is saved, the production cost is reduced, the resource utilization rate is improved, the basalt fiber is uniformly and disorderly distributed on a concrete product, the weight is light, the strength and the toughness of each part of the concrete are enhanced, the obtained concrete is equivalent to or higher than concrete mixed with other fibers, and meanwhile, the heat resistance and the corrosion resistance of the basalt fiber can be kept.

Detailed Description

The present invention will be further illustrated with reference to the following specific examples.

In the following examples 1 to 12, the cement was 42.5 ordinary portland cement and the mineral admixture was 2.5g/cm in apparent density ³4550cm in specific surface area ²The additive is a water reducing agent with the water reducing rate of 27 percent, the bleeding rate of 20 percent and the gas content of 3.7 percent, the coarse aggregate is graded broken stone with the particle size of 5-20mm, and the fine aggregate is continuous graded medium sand with the fineness modulus of 2.7.

The method of making the fiber self-compacting concrete of examples 1-12 below, comprising the steps of:

s1, uniformly mixing the fine aggregate and the coarse aggregate to obtain a primary mixed material;

s2, slowly adding basalt fibers into the primary mixed material under the stirring state, then adding an additive, and uniformly stirring to obtain a secondary mixed material;

and S3, adding water into the secondary mixed material under the stirring state, uniformly stirring, adding cement and mineral admixture, and stirring for 3-5 min.

Example 1

The fiber self-compacting concrete comprises the following raw materials in unit volume: 330kg/m cement ³144kg/m of mineral blend ³835kg/m of coarse aggregate ³797.6kg/m of fine aggregate ³Additive 44.8kg/m ³178kg/m of water ³。

Example 2

The fiber self-compacting concrete comprises the following raw materials in unit volume: 334kg/m cement ³Mineral blend 140kg/m ³842.8kg/m coarse aggregate ³790kg/m of fine aggregate ³Chopped basalt fiber 8.4kg/m ³34.3kg/m of water reducing agent ³182kg/m of water ³。

The monofilament diameter is 13 mu m, and the density is 2800kg/m ³Chopped basalt fibers having a tensile modulus of 105GPa, a tensile strength of 3900MPa and an elongation at break of 2.7% were blended in the following examples 4 to 12. The raw material ratios of examples 3 to 12 were as follows:

the fiber self-compacting concrete obtained in examples 3 to 12 was subjected to performance testing, specifically as follows:

wetting the collapsed bucket and the ground with water before filling to prevent the water of the concrete from being absorbed, filling the mixed concrete into the collapsed bucket, leveling the concrete when the concrete is flush with the upper surface of the collapsed bucket, quickly lifting the collapsed bucket, and measuring the time T required for the concrete to expand from the beginning of flowing to the collapse of 500mm ₅₀₀；

And (3) putting the mixed concrete into a mould with the size of 100mm multiplied by 100mm, curing for 7d and 28d under the conditions of 20 ℃ and 95% of relative humidity, and carrying out uniaxial sample treatment on the cured concrete sample at the loading speed of a testing machine of 0.5 Mpa/s.

The results are shown in the following table:

the experimental results of slump show that: concrete T doped with basalt fiber ₅₀₀All are larger than the unblended concrete (example 3), while the concrete T incorporating the pretreated chopped basalt fibers ₅₀₀Is larger than the concrete doped with the chopped basalt fiber, and the longer the fiber length is, the T is ₅₀₀The larger.

The concrete added with basalt fibers has slightly poorer fluidity than that of a control group, but when the same slump is achieved, the concrete time of adding 5mm fibers with the content of 0.1% is only increased by 0.86s, the concrete time of adding 5mm fibers with the content of 0.3% is only increased by 5.51s, the increase time is shorter, and all the concrete added with basalt fibers can achieve the same slump as that of the concrete of the control group.

The uniaxial compression test result shows that: the concrete 28d without basalt fiber is 48.1MPa in compressive strength, the concrete 28d with chopped basalt fiber is greater than the control group (example 3), and the concrete 28d with pretreated chopped basalt fiber is higher than the concrete with chopped basalt fiber.

The fiber self-compacting concrete obtained by the invention has excellent fluidity and obviously improved compressive strength, and can meet the application of engineering practice.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims (10)

1. The fiber self-compacting concrete is characterized by comprising the following raw materials in unit volume: cement 330- ³Mineral admixture 140-144kg/m ³835-842.8kg/m of coarse aggregate ³790-797.6kg/m of fine aggregate ³0-8.4kg/m of basalt fiber ³34.3 to 44.8kg/m of additive ³178- ³。

2. The fiber self-compacting concrete according to claim 1, wherein the basalt fiber is a chopped basalt fiber having a length of 5-24mm, a monofilament diameter of 10-15 μm, a density of 2600-3000kg/m ³The tensile modulus is 100-110GPa, the tensile strength is 3800-4000MPa, and the elongation at break is 2.5-3.0%.

3. The fiber self-compacting concrete according to claim 2, wherein the chopped basalt fiber has a maximum working temperature of 650 ℃ and an alkali resistance property of 78-82% retention of the breaking strength of the monofilament.

4. The fibrous self-compacting concrete according to claim 1, characterized in that the cement is ordinary portland cement and has a strength rating of 42.5, 52.5 and/or 62.5.

5. The fiber self-compacting concrete of claim 1, wherein the mineral admixture is fly ash having an apparent density of 2-3g/cm ³The specific surface area is 4500- ²/g。

6. The fiber self-compacting concrete of claim 5, wherein the fineness of the fly ash is 8-10%, the water demand ratio is 85-90%, and the loss on ignition is 4.0-4.5%.

7. The fiber self-compacting concrete of claim 1, wherein the admixture is a water reducing agent, and has a water reducing rate of 25-30%, a bleeding rate of 18-22%, and a gas content of 3.5-4.0%.

8. The fiber self-compacting concrete according to claim 1, wherein the coarse aggregate is graded crushed stone, and the grain composition is 5-20 mm.

9. The fiber self-compacting concrete according to claim 1, wherein the fine aggregate is continuous graded medium sand, and the fineness modulus is 2.5-3.0.

10. A method of making a fibrous self-compacting concrete according to any one of claims 1-9, comprising the steps of:

s1, uniformly mixing the fine aggregate and the coarse aggregate to obtain a primary mixed material;

s2, slowly adding basalt fibers into the primary mixed material under the stirring state, then adding an additive, and uniformly stirring to obtain a secondary mixed material;

and S3, adding water into the secondary mixed material under the stirring state, uniformly stirring, and then adding cement and mineral admixture and stirring.