CN112047670A - C40 polypropylene fiber-doped anti-freezing concrete and preparation method thereof - Google Patents

Abstract

The invention discloses C40 polypropylene fiber-doped anti-freezing concrete and a preparation method thereof. The paint comprises the following components in parts by weight: cement 400-450 parts; 0.5-1 part of polypropylene fiber; 750 portions of sand and 800 portions of sand; 1000 portions of stone 950-; 4-5 parts of an additive; 150 portions of water and 200 portions of water. Pouring sand and stones into respective raw material bins for pre-homogenization; placing the pre-homogenized sand and gravel in a forced stirrer, and stirring at a speed of 3-6r/min for 2 min; adding cement, fiber, a polycarboxylic acid water reducing agent and water into a forced stirrer, stirring for 5min, adding an XT-HPA environment-friendly high-permeability inorganic crystalline waterproofing agent, and stirring for 2 min. The inorganic coating and the polypropylene fiber are added, so that the waterproof, bonding and anti-cracking performance of the concrete is improved, and the frost resistance and durability of the concrete are improved.

Description

C40 polypropylene fiber-doped anti-freezing concrete and preparation method thereof

Technical Field

The invention relates to C40 polypropylene fiber-doped anti-freezing concrete and a preparation method thereof, belonging to the technical field of concrete.

Background

Most areas in China belong to severe cold regions, and the requirement on the frost resistance of buildings is high. Under the conditions of severe cold and extreme temperature difference, the internal and external contraction of the conventional concrete is inconsistent, so that the internal stress of the concrete is increased, and cracks are generated.

In order to improve the frost resistance of concrete, an inorganic coating is usually added to the concrete, and the bonding property and the waterproof property of the concrete are enhanced depending on the performance of the inorganic coating. However, in the later stage of concrete curing, fine cracks still can be generated inside concrete due to large temperature difference between the inside and the outside in severe cold areas, and the internal cracks gradually increase along with continuous freezing and melting, so that the strength of the whole concrete construction building is influenced.

Disclosure of Invention

In view of the above, the invention provides the C40 polypropylene fiber-doped anti-freezing concrete and the preparation method thereof, and the inorganic coating and the polypropylene fiber are added to improve the waterproof, bonding and anti-cracking performance of the concrete, thereby improving the frost resistance and durability of the concrete.

The invention solves the technical problems by the following technical means:

the invention relates to C40 polypropylene fiber-doped anti-freezing concrete which comprises the following components in parts by weight:

the additive comprises an XT-HPA environment-friendly high-permeability inorganic crystalline waterproofing agent and a polycarboxylic acid water reducing agent in a weight ratio of 1: 1.

The stones are continuously graded with a particle size of 5-25 mm.

The sand uses natural medium sand in the II area.

The polypropylene fibers used were 30 μm in diameter and 12mm in length.

A preparation method of C40 polypropylene fiber-doped anti-freezing concrete comprises the following steps:

1) pouring sand and pebbles into respective raw material bins for pre-homogenization, wherein the pre-homogenization time is 5-10min, and the stirring speed is 5-10 r/min;

2) placing the pre-homogenized sand and gravel in a forced stirrer, and stirring at a speed of 3-6r/min for 2 min;

3) adding cement, fiber, a polycarboxylic acid water reducing agent and water into a forced stirrer, stirring for 5min, adding an XT-HPA environment-friendly high-permeability inorganic crystalline waterproofing agent, and stirring for 2 min.

The invention takes sand and stones as basic lapping frameworks of concrete, the quantity of the stones is larger, and the sand is filled in gaps of the stones to form the basic lapping frameworks of the concrete together with the stones. Cement and a water reducing agent are dissolved in water to form viscous slurry, and the slurry is wrapped on the outside of the lap joint frameworks to enhance the bonding effect between the lap joint frameworks, so that the strength of the concrete basic framework is improved. The XT-HPA is added into concrete to raise the adhesion and prevent concrete shrinkage crack. The fiber can effectively inhibit the generation and development of concrete cracks by utilizing the bridging effect, thereby efficiently improving the anti-cracking performance of the concrete.

In addition, the admixture comprises XT-HPA penetration type and polycarboxylic acid water reducing agent. The XT-HPA penetration type can improve the bonding property between the concrete lap joint framework and the slurry, and the polycarboxylic acid water reducing agent added into the concrete can further reduce the water consumption and increase the bonding strength between the lap joint frameworks.

The invention uses the stones with 5-25mm continuous gradation as basic lapping frameworks, the sizes of the stones are different, the stones with smaller particles are filled among the stones with larger particle sizes, and the concrete frameworks with different lapping levels are integrally formed. The natural medium sand in the area II has smaller grain diameter and is filled in gaps among stones, so that the strength of the lapped framework is further enhanced. The polypropylene fiber can effectively inhibit the generation and development of concrete cracks by utilizing the bridging effect, thereby efficiently improving the anti-cracking performance of the concrete.

According to the formula disclosed by the invention, the concrete prepared by using the proportion has good compressive property, and the strength loss is small after multiple freeze-thaw cycles.

According to the preparation method, after the sand and the stones are pre-homogenized, the surfaces of the sand and the stones are mutually rubbed to form a new tangent plane, so that the sand and the stones are easily mixed with the slurry, and the adhesive force is strong.

When the concrete is prepared, sand and stones for constructing the concrete framework are uniformly stirred in advance, and then the sand and the stones are mixed with cement, polypropylene fibers and a water reducing agent to form a uniformly dispersed concrete system. And then, an XT-HPA environment-friendly high-permeability inorganic crystalline waterproof agent is added and stirred, and the slurry, the sand and the stones are bonded by an XT-HPA environment-friendly high-permeability inorganic crystalline waterproof agent solution, so that the coating is tighter.

The invention has the following beneficial effects:

1. the continuous graded stones and sands are mutually filled and overlapped to form a stable concrete framework, so that the compressive strength of the concrete is increased.

2. The XT-HPA environment-friendly high-permeability inorganic crystalline waterproofing agent is added into the concrete, so that the bonding effect between the basic lap joint framework of the concrete and the gel substance is improved.

3. The polypropylene fiber is added into the concrete, so that the generation and the development of concrete cracks can be effectively inhibited, and the anti-cracking performance of the concrete is improved.

4. The water reducing agent is a polycarboxylic acid water reducing agent, so that the bonding strength of the lap joint framework and the gel substance in the concrete is further improved.

Drawings

FIG. 1 shows the preparation method of the anti-freezing concrete with polypropylene fiber blended in C40 according to the present invention.

Detailed Description

The C40 polypropylene fiber-doped anti-freezing concrete comprises the following components in parts by weight:

the additive comprises an XT-HPA environment-friendly high-permeability inorganic crystalline waterproofing agent and a polycarboxylic acid water reducing agent in a weight ratio of 1: 1.

The stones are continuously graded with a particle size of 5-25 mm.

The sand uses natural medium sand in the II area.

The polypropylene fibers used were 30 μm in diameter and 12mm in length.

A preparation method of C40 polypropylene fiber-doped anti-freezing concrete comprises the following steps:

1) pouring sand and pebbles into respective raw material bins for pre-homogenization, wherein the pre-homogenization time is 5-10min, and the stirring speed is 5-10 r/min;

2) placing the pre-homogenized sand and gravel in a forced stirrer, and stirring at a speed of 3-6r/min for 2 min;

3) adding cement, fiber, a polycarboxylic acid water reducing agent and water into a forced stirrer, stirring for 5min, adding an XT-HPA environment-friendly high-permeability inorganic crystalline waterproofing agent, and stirring for 2 min.

Example 1

The present invention is described in further detail below with reference to fig. 1.

The raw materials according to the present invention are all commercially available, and specific specifications are shown in table 1.

TABLE 1 specification and manufacturer of raw materials used in the examples

Components	Specification of
		Cement	42.5 grade ordinary portland cement
Fiber	Polypropylene fiber with diameter of 30 mu m and length of 12mm
		Sand	Natural medium sand in zone II
Stone	Crushed stone of 5-25mm
		XT-HPA environment-friendly high-permeability inorganic crystalline waterproofing agent	—
Water reducing agent	Polycarboxylic acid water reducing agent

A method for preparing polypropylene fiber frost resistant concrete, comprising the following steps:

the method comprises the following steps: 785kg of sand and 999kg of pebbles are introduced into respective raw material bins for pre-homogenization;

step two: 785kg of sand and 999kg of stones are put in a forced stirrer to be stirred for 2 min;

step three: 440kg of cement, 0.8kg of polypropylene fiber and 2.2kg of water reducing agent are added into a forced stirrer to be stirred for 5min, and then 2.2kgXT-HPA environment-friendly high-permeability inorganic crystalline waterproof agent is added to be stirred for 2 min.

Wherein the admixture comprises the following components in percentage by weight of 1:1 XT-HPA environment-friendly high-permeability inorganic crystalline waterproofing agent and polycarboxylic acid water reducing agent.

The freeze-thaw cycle test of the antifreeze concrete doped with the polypropylene fibers prepared according to the proportion is carried out according to the specification of a quick freeze-thaw test in a test method for long-term durability and durability of common concrete (GBJ82-85), and the dynamic elastic modulus and the quality of the freeze-thaw cycle test are tested; the compressive strength is in accordance with GB/T50081-2002 Standard of mechanical Properties test methods of ordinary concrete.

The antifreeze performance test of the C40 polypropylene fiber-doped concrete is as follows: placing the concrete test block and the test piece which are maintained in the water saturation state for 28 days into a rubber barrel, placing the rubber barrel into a rapid freeze-thaw circulating machine for freeze-thaw circulating test, wherein the water surface is 2cm higher than that of the concrete test block and the test block, the concrete test block and the test block are in the water saturation state in the freeze-thaw process, and the compression strength, the dynamic elastic modulus and the quality are tested every 50 times of freeze-thaw circulation. The freezing resistance coefficient, the relative dynamic elastic modulus and the mass loss are respectively obtained for 300 times, and the three types of test data are specifically shown in table 2.

Table 2 shows three types of test data of the inorganic coating anti-freeze concrete

From the above data, the initial compressive strength, the dynamic elastic modulus and the mass of the concrete prepared by the above formulation are 66.31MPa, 48.58GPa and 10.0172kg respectively, and the concrete can bear enough strength. After 300 times of circulating freeze thawing, the freeze resistance coefficient, the relative dynamic elastic modulus and the mass loss rate are 76.85%, 61.24% and 1.01%, wherein the relative dynamic elastic modulus is higher than 60%, and the mass loss rate is far lower than 5%, so that the national standard of testing method of long-term durability and durability of common concrete (GBJ82-85) is met, meanwhile, the mass loss rate of the concrete is lower due to the fact that the inorganic coating and the polypropylene fibers are doped, the compressive strength is far higher than the standard of C40 concrete, cracks are not generated on the surface of the concrete after 300 times of circulating freeze thawing, the strength is reduced slightly, and the concrete has good freeze resistance.

The admixture uses an XT-HPA environment-friendly high-permeability inorganic crystalline waterproofing agent and a polycarboxylic acid water reducing agent in a weight ratio of 1:1, so that the using amount of water in concrete is reduced, and the viscosity of the slurry is increased. The bonding between the lapping skeleton formed by the sand and the stones and the slurry is firmer under the action of an XT-HPA environment-friendly high-permeability inorganic crystalline waterproofing agent and a polycarboxylic acid water reducing agent, so that the frost resistance of the concrete is improved.

Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.

Claims (5)

1. The C40 polypropylene fiber-doped anti-freezing concrete is characterized by comprising the following components in parts by weight:

the additive comprises an XT-HPA environment-friendly high-permeability inorganic crystalline waterproofing agent and a polycarboxylic acid water reducing agent in a weight ratio of 1: 1.

2. The C40 polypropylene fiber-doped anti-freezing concrete as claimed in claim 1, wherein: the stones are continuously graded with a particle size of 5-25 mm.

3. The C40 polypropylene fiber-doped anti-freezing concrete as claimed in claim 1, wherein: the sand uses natural medium sand in the II area.

4. The method for preparing C40 antifreeze concrete according to claim 1, wherein: the polypropylene fibers used were 30 μm in diameter and 12mm in length.

5. A preparation method of C40 polypropylene fiber-doped anti-freezing concrete is characterized by comprising the following steps:

1) pouring sand and pebbles into respective raw material bins for pre-homogenization, wherein the pre-homogenization time is 5-10min, and the stirring speed is 5-10 r/min;

2) placing the pre-homogenized sand and gravel in a forced stirrer, and stirring at a speed of 3-6r/min for 2 min;

3) adding cement, fiber, a polycarboxylic acid water reducing agent and water into a forced stirrer, stirring for 5min, adding an XT-HPA environment-friendly high-permeability inorganic crystalline waterproofing agent, and stirring for 2 min.

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