Method for improving interface bonding of fiber fabric and cement-based material

Abstract

The invention discloses a method for improving interface bonding of a fiber fabric and a cement-based material, and relates to the technical field of building materials. Plied yarns and a short fiber fabric are arranged in a cement matrix, and after multiple times of vibration operation, the fiber fabric and the cement-based material are bonded; according to the present invention, the long fiber fabric and the short fiber fabric are combined, the modified nano-composite coating is arranged on the surface of the fiber fabric, and the interface reinforcing agent is additionally used, such that the compression resistance and the crack resistance of the concrete can be effectively improved; according to the cement-based material, the anti-compression and anti-cracking capabilities are effectively improved, twisted plied yarns are arranged, the probability of agglomeration of the long fiber fabric is reduced in a pressing, cutting and vibrating manner, and the plied yarns are not in a parallel state but are in a rotary hourglass shape when being dispersed, so that the interface bonding capability of the fiber fabric and the cement-based material can be improved, and the bonding strength of the fiber fabric and the cement-based material is improved. And the concrete can have excellent compression resistance and tensile property.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, and in particular to a method for improving the interface bonding between fiber fabrics and cement-based materials. Background Art

[0002] Fiber fabric reinforced cement-based composite materials have been widely used in the field of civil engineering due to their excellent mechanical properties, light weight, high strength and corrosion resistance. Especially when paving roads, in addition to using steel bars, fiber fabrics mixed with concrete for paving roads are also a common way to avoid cracking of roads, interior and exterior wall panels, and ceilings at joints on roads such as bridges.

[0003] However, the interfacial bonding performance between the fiber fabric and the cement matrix directly affects the overall mechanical properties and durability of the composite material. At present, the fiber fabrics added to the cement matrix include steel fibers, polypropylene fibers, glass fibers, mineral fibers and calcium silicate fibers. The prior art also uses fiber fabrics of special materials such as carbon fibers for incorporation into the cement matrix. When mixing the fiber fabric with the cement matrix, the current mixing method usually adopts a direct mixing method or a two-stage mixing method. However, whether it is a direct mixing method or a two-stage mixing method, when using steel fibers, because the steel fibers themselves have sufficient rigidity, the mixing equipment is not easy to change the shape of the steel fibers during mixing. The steel fibers and the cement matrix can be mixed evenly by stirring and mixing, and the rigidity of the steel fibers can form a disordered and uniform fiber network in the cement matrix, so that crack resistance, reinforcement and toughening effects can be obtained. However, when fibers of other materials are stirred, mixed and laid, the agitator tends to cause the fibers to agglomerate. Although the subsequent vibration process can remove bubbles and stretch the fibers to a certain extent, it is still difficult for the fibers to be evenly distributed in the cement matrix. Moreover, the fibers tend to agglomerate into balls, which cannot achieve a good toughening effect.

[0004] The existing technology usually adopts the method of increasing the amount of fiber fabric or reducing the fiber length. However, increasing the amount of fiber fabric will affect the strength of concrete. Reducing the fiber length, when using fiber fabrics with small surface friction and small diameter, the fiber fabrics have low bonding strength with cement-based materials due to their own properties, and the fiber fabrics cannot be well fixed with the cement-based materials, thereby failing to enhance the tensile strength of concrete. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a method for improving the interfacial bonding between fiber fabrics and cement-based materials while maintaining the strength of concrete.

[0006] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0007] A method for improving the interfacial bonding between a fiber fabric and a cement-based material is provided, comprising the following steps:

[0008] S1: twisting the fiber fabric into strands, and evenly arranging a plurality of strands at intervals on the road surface to be paved with concrete, with the length direction of the strands perpendicular to the road surface joint; the fiber fabric is polypropylene fiber, glass fiber, mineral fiber or calcium silicate fiber;

[0009] S2: pouring and paving the cement matrix on the road surface, the cement matrix covers several strands of wire, and using tools to preliminarily scrape the cement matrix;

[0010] S3: Before the cement matrix solidifies, the strands are cut into several even parts, and short fiber fabrics are spread on the surface of the cement matrix;

[0011] S4: Use a flat vibrator to vibrate the cement matrix to embed the short fiber fabric into the cement matrix, complete the operation, and wait for the cement matrix to solidify.

[0012] Furthermore, steps S3 and S4 are specifically as follows:

[0013] A1: Use a press knife to cut the strands perpendicular to the paving surface. After the press knife is pulled out, fill the groove created by the press knife on the cement matrix with short fiber fabric;

[0014] A2: Use a flat vibrator for the first vibration operation, the vibration time is 50 to 80 seconds;

[0015] A3: Evenly spread short-fiber fabric on the surface after the first vibration operation, and use a flat vibrator for the second vibration operation, with a vibration time of 30 to 40 seconds.

[0016] Furthermore, the length of the short fiber fabric is 3 to 5 cm, and the spreading of the short fiber fabric in step S303 is performed 2 to 4 times, each time the short fiber fabric is spread to cover 80 to 85% of the surface area of ​​the laying surface, and the short fiber fabric is adhered to the cement matrix and will not fly up, and a vibration operation is performed for 30 to 40 seconds after each spreading.

[0017] Furthermore, the cement matrix is ​​obtained by mixing the adhesive, filler and water in a mass ratio of 1:1.5-2:0.75-1.15.

[0018] Furthermore, the adhesive material is obtained by mixing silicate cement, fly ash and silica fume in a mass ratio of 2:2:1.

[0019] Furthermore, the cement matrix is ​​doped with an interface enhancer accounting for 0.5 to 1% of the total mass.

[0020] Furthermore, the cutting length of the strands And α=f(k)=2π·b-k +c; where b is the standard consistency of the adhesive, c is the correction factor, h is the set laying thickness of the cement matrix, and k is the water-powder ratio of the cement matrix; the spacing between two adjacent strands

[0021] Furthermore, the surface of the fiber fabric is also covered with a modified nanocomposite coating, and the specific coating method is as follows:

[0022] B1: A composite solution is prepared using nano-SiO2, silane coupling agent and deionized water;

[0023] B2: Immerse the fiber fabric completely in the composite solution to ensure sufficient wetting;

[0024] B3: Ultrasonic reaction is carried out at 60-100° C. for 0.5-2 hours. After the ultrasonic reaction is completed, the fiber fabric is dried to form a modified nano-composite coating on the surface of the fiber fabric.

[0025] Furthermore, the content of nano silicon dioxide in the composite solution is 5% to 8%, and the content of silane coupling agent is 3% to 5%.

[0026] Furthermore, the center of the strands twisted from the fiber fabric is also filled with polyurethane microcapsules.

[0027] The beneficial effects of the present invention are:

[0028] The present invention can effectively improve the compression and crack resistance of concrete by arranging strands and short fiber fabrics in a cement matrix, arranging a modified nano-composite coating on the surface of the fiber fabric by combining longer fiber fabrics with the short fiber fabrics after multiple vibration operations, and increasing the use of an interface enhancer. Compared with the prior art, which uses fiber fabrics for two-stage mixed pouring, the compression and crack resistance are effectively improved. Twisted strands are arranged, and the probability of agglomeration of longer fiber fabrics is reduced by cutting and vibrating. Moreover, when the strands are spread out, they are not in a parallel state, but in a rotating hourglass shape. This method can increase the interfacial bonding ability of the fiber fabric and the cement-based material, and enable the concrete to have excellent compression and tensile properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0030] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0031] Example 1

[0032] like Figure 1 As shown, a method for improving the interfacial bonding between a fiber fabric and a cement-based material comprises the following steps:

[0033] S1: twisting the fiber fabric into strands, and evenly arranging a plurality of strands at intervals on the road surface to be paved with concrete, with the length direction of the strands perpendicular to the road surface joint; the fiber fabric is polypropylene fiber, glass fiber, mineral fiber or calcium silicate fiber;

[0034] S2: Pour the cement matrix on the road surface, bury the several strands of wires with the cement matrix, and use tools to preliminarily scrape the cement matrix; the cement matrix is ​​obtained by mixing the adhesive, filler and water in a mass ratio of 1:1.5-2:0.75-1.15. The adhesive is obtained by mixing silicate cement, fly ash and silica fume in a mass ratio of 2:2:1. The cement matrix is ​​also mixed with an interface enhancer accounting for 0.5-1% of the total mass. In the specific implementation, the filler is sand and gravel, and the D90 particle size of the crushed stone in the sand and gravel does not exceed 5mm.

[0035] S3: Before the cement matrix solidifies, the strands are cut into several even parts, and short fiber fabrics are spread on the surface of the cement matrix;

[0036] Cutting length of strands And α=f(k)=2π·b -k +c; where b is the standard consistency of the adhesive, c is the correction factor, h is the set laying thickness of the cement matrix, and k is the water-powder ratio of the cement matrix; the spacing between two adjacent strands The standard consistency of the adhesive is determined by measuring the consistency meter around the road surface before paving. The correction factor is determined by the properties of the adhesive itself and the different purchased or produced silicate cement, fly ash and silica fume. f(k) is a function related to the water-powder ratio of the cement matrix.

[0037] A1: Use a press knife to cut the strands perpendicular to the paving surface. After the press knife is pulled out, fill the groove created by the press knife on the cement matrix with short fiber fabric;

[0038] A2: Use a flat vibrator for the first vibration operation, the vibration time is 50 to 80 seconds;

[0039] A3: Evenly spread short fiber fabric on the surface after the first vibration operation, and use a flat vibrator to perform the second vibration operation, and the vibration time is 30-40 seconds. The length of the short fiber fabric is 3-5 cm, and the short fiber fabric is spread 2-4 times. Each time the short fiber fabric is spread, it covers 80-85% of the surface area of ​​the paving surface, and the short fiber fabric is adhered to the cement matrix and does not fly up. After each spreading, a vibration operation is performed for 30-40 seconds.

[0040] S4: Use a flat vibrator to vibrate the cement matrix to embed the short fiber fabric into the cement matrix, complete the operation, and wait for the cement matrix to solidify.

[0041] The surface of the fiber fabric is also covered with a modified nano-composite coating, and the specific coating method is as follows:

[0042] B1: Prepare a composite solution using nano-SiO2, silane coupling agent and deionized water; the content of nano-SiO2 in the composite solution is 5% to 8%, and the content of silane coupling agent is 3% to 5%. In specific implementation, the silane coupling agent can be selected from organic silane of KH550, KH560 or KH570.

[0043] B2: Immerse the fiber fabric completely in the composite solution to ensure sufficient wetting;

[0044] B3: Ultrasonic reaction is carried out at 60-100° C. for 0.5-2 hours. After the ultrasonic reaction is completed, the fiber fabric is dried to form a modified nano-composite coating on the surface of the fiber fabric.

[0045] The center of the strands twisted from the fiber fabric is also filled with polyurethane microcapsules. In specific implementation, the fiber fabric twisting process is in a vertical state, a box is provided at the twisting line, the strands pass through the box from top to bottom, dry polyurethane microcapsules are placed in the box, and the twisting line is buried in the dry polyurethane microcapsules. During the twisting process of the fiber fabric, the polyurethane microcapsules are wrapped around the center of the strands by a number of fiber fabrics. When the polyurethane microcapsules are cracked and lost inside the subsequent pavement, the polymer emulsion in the microcapsule flows out after the capsule wall cracks under the action of stress. Because the strands inside the concrete are long and gaps are easily generated after the strands are spread out, although the generation of gaps can be effectively avoided by vibration operation, the longer fiber fabrics are more likely to crack in the later use than other positions, and the polymer emulsion in the polyurethane microcapsule can effectively fill the cracks, and the polymer emulsion can directly strengthen the bonding between the longer fiber fabrics generated by the spread of the strands and the cracks through capillary action.

[0046] Example 2

[0047] The method of Example 1 was used to prepare concrete samples, and several concrete samples with a side length of 0.8m and a thickness of 15cm were prepared. In this embodiment, polypropylene fiber was used to prepare strands and cut into 3cm short fiber fabrics. In other embodiments of the present invention, the length of the short fiber fabric can also be selected to be 4 or 5cm, which is specifically determined according to the thickness of the road surface. The cutting length of the strands in each sample is 12cm, and the interval between two adjacent strands is 14.7cm; the vibration operation uses a FL series 30 vibration motor 30W and a flat plate simulation operation, and the preparation parameters of each concrete sample are shown in Table 1; in this embodiment, the interface enhancer is prepared by a composite preparation of acrylic emulsion and nano-SiO2 at a mass ratio of 7:3. The silicate cement, fly ash, silica fume and filler used in this embodiment are all from the products sold by China Resources Building Materials. The model of acrylic emulsion is SEACRYL 11K20, and the model of nano-SiO2 is CAB-O-SIL LM150.

[0048] Table 1

[0049]

[0050] When the modified nanocomposite coating was applied to the strands of Samples 6 to 8, ultrasonic reaction was performed for 1 hour at 80° C. In other embodiments of the present invention, the temperature for applying the modified nanocomposite coating can also be 60, 70, 90 or 100° C., and the ultrasonic reaction time can also be 0.5, 0.7, 1.5 or 2 hours.

[0051] The prepared samples were subjected to compression and crack resistance tests. The test reference was GB / T50082-2009 "Standard for Test Methods of Long-term Performance and Durability of Ordinary Concrete". A control sample was also set. The control sample was obtained by using short fiber fabrics of the same volume and pouring and vibrating after the existing two-stage mixing. The other parameters were consistent with sample 1. The test results are shown in Table 2.

[0052] Table 2

[0053] 28d compressive strength / MPa <![CDATA[Surface cracking area (mm 2 / m 2 )]]> Sample 1 61 582.0 Sample 2 63 643.9 Sample 3 61 718.3 Sample 4 59 517.6 Sample 5 68 415.1 Sample 6 73 272.3 Sample 7 72 203.1 Sample 8 74 196.0 Comparison 55 834.2

[0054] As can be seen from Table 2, the samples with added strands and short fiber fabrics have better compressive strength and surface crack area at 28 days than the control samples without additions, and samples 5-8 with added interface enhancers are significantly better than samples 1-4. After the modified nano-composite coating is coated on the surface of the strands with a composite solution, the compressive and crack resistance of the samples are also enhanced.

Claims

1. A method for improving the interfacial bonding between a fiber fabric and a cement-based material, characterized in that: The steps include: S1: twisting the fiber fabric into strands, and evenly arranging a plurality of strands at intervals on the road surface to be paved with concrete, with the length direction of the strands perpendicular to the road surface joint; the fiber fabric is polypropylene fiber, glass fiber, mineral fiber or calcium silicate fiber; S2: pouring and paving the cement matrix on the road surface, the cement matrix covers several strands of wire, and using tools to preliminarily scrape the cement matrix; S3: Before the cement matrix solidifies, the strands are cut into several even parts, and short fiber fabrics are spread on the surface of the cement matrix; S4: Use a flat vibrator to vibrate the cement matrix to embed the short fiber fabric into the cement matrix, complete the operation, and wait for the cement matrix to solidify.

2. The method for improving the interfacial bonding between fiber fabric and cement-based material according to claim 1, characterized in that: The steps S3 and S4 are specifically as follows: A1: Use a press knife to cut the strands perpendicular to the paving surface. After the press knife is pulled out, fill the groove created by the press knife on the cement matrix with short fiber fabric; A2: Use a flat vibrator for the first vibration operation, the vibration time is 50 to 80 seconds; A3: Evenly spread short-fiber fabric on the surface after the first vibration operation, and use a flat vibrator for the second vibration operation, with a vibration time of 30 to 40 seconds.

3. The method for improving the interfacial bonding between fiber fabric and cement-based material according to claim 2, characterized in that: The length of the short fiber fabric is 3 to 5 cm, and the short fiber fabric is spread 2 to 4 times in step S303. Each time the short fiber fabric is spread, 80 to 85% of the surface area of ​​the laying surface is covered, and the short fiber fabric is adhered to the cement matrix and does not fly up. After each spreading, a vibration operation is performed for 30 to 40 seconds.

4. The method for improving the interfacial bonding between fiber fabric and cement-based material according to claim 1, characterized in that: The cement matrix is ​​obtained by mixing a glue material, a filler and water in a mass ratio of 1:1.5-2:0.75-1.

15.

5. The method for improving the interfacial bonding between fiber fabric and cement-based material according to claim 4, characterized in that: The adhesive material is obtained by mixing silicate cement, fly ash and silica fume in a mass ratio of 2:2:

1.

6. The method for improving the interfacial bonding between fiber fabric and cement-based material according to claim 4, characterized in that: The cement matrix is ​​also doped with an interface enhancer accounting for 0.5-1% of the total mass.

7. The method for improving the interfacial bonding between fiber fabric and cement-based material according to claim 4, characterized in that: Cutting length of strands And α=f(k)=2π·b -k +c; where b is the standard consistency of the adhesive, c is the correction factor, h is the set laying thickness of the cement matrix, and k is the water-powder ratio of the cement matrix; the spacing between two adjacent strands 8. The method for improving the interfacial bonding between fiber fabric and cement-based material according to claim 1, characterized in that: The surface of the fiber fabric is also covered with a modified nanocomposite coating, and the specific coating method is as follows: B1: A composite solution is prepared using nano-SiO2, silane coupling agent and deionized water; B2: Immerse the fiber fabric completely in the composite solution to ensure sufficient wetting; B3: Ultrasonic reaction is carried out at 60-100° C. for 0.5-2 h. After the ultrasonic reaction is completed, the fiber fabric is dried to form a modified nano-composite coating on the surface of the fiber fabric.

9. The method for improving the interfacial bonding between fiber fabric and cement-based material according to claim 8, characterized in that: The content of nano silicon dioxide in the composite solution is 5% to 8%, and the content of silane coupling agent is 3% to 5%.

10. The method for improving the interfacial bonding between fiber fabric and cement-based material according to claim 1, characterized in that: The centers of the strands twisted from the fiber fabric are also filled with polyurethane microcapsules.

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