Concrete water-permeable template cloth capable of automatically repelling cement particles

Abstract

The utility model discloses concrete water-permeable formwork cloth capable of automatically repelling cement particles. The concrete water-permeable formwork cloth is composed of a repelling layer, a water guide layer and a base body layer. The repelling layer is an anionic polymer film or anionic modified non-woven fabric; the water guide layer comprises an upper layer, a middle layer and a lower layer, and the aperture is gradually increased from top to bottom. The repulsion layer is bonded with the upper layer of the water guide layer through an ultrasonic welding process, and the lower layer of the water guide layer is connected with the base body layer through hot-pressing bonding. Compared with common permeable template cloth, the water guide layer is arranged to be in a three-layer aperture gradient form, so that water discharge can be accelerated, water accumulation is prevented, and permeable pressure is reduced; the surface of the permeable template cloth is provided with the repelling layer with anions, so that the permeable template cloth has the effects of automatically repelling cement particles, preventing clogging and increasing the use frequency of the permeable template cloth.

Description

Technical Field

[0001] This utility model belongs to the field of concrete curing technology in civil engineering, and specifically relates to a permeable concrete formwork cloth with self-repelling cement particles. Background Technology

[0002] Large-volume concrete structures such as bridges and box culverts often suffer from defects like honeycomb and air holes on the hardened concrete surface due to uneven vibration and changes in the curing environment during the concrete pouring process, affecting aesthetics and durability. While permeable formwork can effectively improve these defects, existing permeable formwork suffers from clogging during use, as cement particles from the concrete can enter and clog it, significantly reducing its effectiveness for reuse and increasing maintenance costs.

[0003] To address this issue, Chinese patent (CN101644106A) discloses a method for regenerating clogged permeable formwork fabric. This method involves soaking the permeable formwork fabric in dilute hydrochloric acid to remove clogs. Chinese utility model patent (CN201311390Y) discloses a device for testing the permeability and clog resistance of permeable formwork fabric for concrete. However, this patent only addresses the device for testing clog resistance and does not involve preventing clogs. Chinese patents (CN215631563U, CN205476433U, CN202117327U, CN102661036A) all concern the structural design of permeable formwork fabric and do not possess a self-repelling cement particle function. Summary of the Invention

[0004] The purpose of this invention is to provide a permeable template fabric that can repel cement particles. The surface of cement particles carries a negative charge during the hydration process. Based on the principle of charge repulsion, an anionic repulsion layer is designed to prevent cement particles from adhering and penetrating.

[0005] The technical solution adopted in this utility model is as follows:

[0006] A permeable concrete formwork fabric with self-repelling cement particles includes a repellent layer, a water-conducting layer, and a substrate layer; the repellent layer is an anionic polymer film or anionic modified nonwoven fabric; the water-conducting layer consists of an upper layer, a middle layer, and a lower layer, with the pore size gradually increasing from top to bottom; the repellent layer is connected to the upper layer of the water-conducting layer, and the lower layer of the water-conducting layer is connected to the substrate layer.

[0007] The pore size of the repellent layer is 0.1~1μm, and the thickness is 0.1~0.3mm. Since the particle size of cement particles is between 1~100μm, this pore size can isolate the penetration of cement particles with the smallest pore size.

[0008] The anionic polymer film is one of polyacrylic acid, sodium polystyrene sulfonate, polyvinyl alcohol sulfonic acid, and sulfonated polyether sulfone.

[0009] The pore size of the water-conducting layer gradually increases from top to bottom. The upper layer has a pore size of 1~3μm and a thickness of 0.2~0.4mm; the middle layer has a pore size of 3~6μm and a thickness of 0.3~0.5mm; and the lower layer has a pore size of 6~10μm and a thickness of 0.3~0.5mm. This three-layer pore size gradient design accelerates water drainage, prevents water accumulation, and reduces permeability pressure.

[0010] Preferably, the upper layer of the water-conducting layer is made of highly absorbent cellulose fiber, while the middle and lower layers are made of porous polyurethane foam. These two materials have stronger water absorption and conductivity than ordinary polyethylene or polypropylene fibers.

[0011] The substrate layer is made of ordinary polyethylene or polypropylene fiber with a thickness of 0.2~0.5mm.

[0012] The surface of the template cloth is provided with an anionic repellent layer, which automatically repels cement particles, preventing clogging and increasing the number of uses of the permeable template cloth.

[0013] The repellent layer, water-conducting layer, and substrate layer can be bonded using conventional bonding methods in the art, such as hot pressing and welding.

[0014] More preferably, the repellent layer and the upper layer of the water-conducting layer are bonded together by ultrasonic welding, the upper, middle and lower layers of the water-conducting layer are connected by hot-press bonding, and the lower layer of the water-conducting layer is connected to the substrate layer by hot-press bonding.

[0015] The specific conditions for ultrasonic welding are as follows: align the upper layer of the repulsion layer and the upper layer of the water-conducting layer and fix them in the fixture of the ultrasonic welding equipment; start the ultrasonic welding equipment, and the welding head begins to vibrate at an ultrasonic frequency of 20kHz~40kHz; after the contact surfaces of the repulsion layer and the upper layer of the water-conducting layer are fused, stop the ultrasonic vibration, and maintain the pressure for a period of time to allow the molten material to cool and solidify, thereby completing the welding.

[0016] Anionic modified nonwoven fabrics are made by introducing polar groups such as carboxyl and hydroxyl groups onto the surface of polypropylene, polyester, and polyurethane nonwoven fabric substrates, thereby giving them a negative charge. Beneficial effects

[0017] By replacing the ordinary fiber material on the surface of ordinary permeable formwork with a polymer film or modified nonwoven fabric with anionic charge, cement particles can be automatically repelled, thus preventing clogging and increasing the number of times the permeable formwork can be used.

[0018] By changing the single-pore drainage layer of ordinary permeable template fabric to a structure with a three-layer pore size gradient, where the pore size gradually increases from top to bottom, water discharge can be accelerated, water accumulation can be prevented, and water pressure can be reduced. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a permeable concrete template fabric with self-repelling cement particles according to this utility model.

[0020] Among them, 1-repellent layer, 2-water-conducting layer, 3-matrix layer, 21-upper layer, 22-middle layer, 23-lower layer. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention. Example

[0022] like Figure 1 As shown, a self-repelling cement particle permeable concrete formwork includes a repelling layer 1, a water-conducting layer 2, and a base layer 3; the water-conducting layer 2 is composed of an upper layer 21, a middle layer 22, and a lower layer 23; the repelling layer 1 is connected to the upper layer 21 of the water-conducting layer 2, and the lower layer 23 of the water-conducting layer 2 is connected to the base layer 3.

[0023] The repulsion layer 1 is an anionic polymer film, specifically any one of polyacrylic acid, sodium polystyrene sulfonate, polyvinyl alcohol sulfonic acid, or sulfonated polyethersulfone film; the pore size is 0.1~1μm and the thickness is 0.1~0.3mm.

[0024] The upper layer 21 of the water-conducting layer is made of highly absorbent cellulose fiber; the middle layer 22 and the lower layer 23 of the water-conducting layer are made of porous polyurethane foam; the matrix layer 3 is made of ordinary polyethylene with a thickness of 0.2~0.5mm.

[0025] The upper layer 21 of the water-conducting layer 2 has a pore size of 1~3μm and a thickness of 0.2~0.4mm; the middle layer 22 of the water-conducting layer 2 has a pore size of 3~6μm and a thickness of 0.3~0.5mm; and the lower layer 23 of the water-conducting layer 2 has a pore size of 6~10μm and a thickness of 0.3~0.5mm.

[0026] The repellent layer 1 and the upper layer 21 of the water-conducting layer 2 are bonded together by ultrasonic welding. The upper layer 21, middle layer 22 and lower layer 23 of the water-conducting layer 2 are connected by hot-press bonding. The lower layer 22 of the water-conducting layer 2 is connected to the substrate layer 3 by hot-press bonding.

[0027] The specific conditions for ultrasonic welding are as follows: align the upper layer of the repulsion layer and the upper layer of the water-conducting layer and fix them in the fixture of the ultrasonic welding equipment; start the ultrasonic welding equipment, and the welding head begins to vibrate at an ultrasonic frequency of 20kHz~40kHz; after the contact surfaces of the repulsion layer and the upper layer of the water-conducting layer are fused, stop the ultrasonic vibration, and maintain the pressure for a period of time to allow the molten material to cool and solidify, thereby completing the welding. Example

[0028] A self-repellent cement particle permeable concrete formwork includes a repellent layer 1, a water-conducting layer 2, and a base layer 3; the water-conducting layer 2 is composed of an upper layer 21, a middle layer 22, and a lower layer 23; the repellent layer 1 is connected to the upper layer 21 of the water-conducting layer 2, and the lower layer 23 of the water-conducting layer 2 is connected to the base layer 3.

[0029] The repulsion layer 1 is an anion-modified nonwoven fabric with a pore size of 0.1~1μm and a thickness of 0.1~0.3mm.

[0030] The upper layer 21 of the water-conducting layer is made of highly absorbent cellulose fiber; the middle layer 22 and the lower layer 23 of the water-conducting layer are made of porous polyurethane foam; the matrix layer 3 is made of polypropylene fiber with a thickness of 0.2~0.5mm.

[0031] The upper layer 21 of the water-conducting layer 2 has a pore size of 1~3μm and a thickness of 0.2~0.4mm; the middle layer 22 of the water-conducting layer 2 has a pore size of 3~6μm and a thickness of 0.3~0.5mm; and the lower layer 23 of the water-conducting layer 2 has a pore size of 6~10μm and a thickness of 0.3~0.5mm.

[0032] The repellent layer 1 and the upper layer 21 of the water-conducting layer 2 are bonded together by ultrasonic welding. The upper layer 21, middle layer 22 and lower layer 23 of the water-conducting layer 2 are connected by hot-press bonding. The lower layer 22 of the water-conducting layer 2 is connected to the substrate layer 3 by hot-press bonding.

[0033] The specific conditions for ultrasonic welding are as follows: align the upper layer of the repulsion layer and the upper layer of the water-conducting layer and fix them in the fixture of the ultrasonic welding equipment; start the ultrasonic welding equipment, and the welding head begins to vibrate at an ultrasonic frequency of 20kHz~40kHz; after the contact surfaces of the repulsion layer and the upper layer of the water-conducting layer are fused, stop the ultrasonic vibration, and maintain the pressure for a period of time to allow the molten material to cool and solidify, thereby completing the welding.

[0034] Anion-modified nonwoven fabrics are specifically manufactured by introducing polar groups such as carboxyl and hydroxyl groups onto the surface of polypropylene, polyester, and polyurethane nonwoven fabric substrates using plasma technology, thus imparting a negative charge and modifying them. The specific process is as follows: First, the nonwoven fabric substrate is placed in a plasma cleaning chamber. A gas (such as oxygen or nitrogen) and a radio frequency power supply are used to generate plasma, cleaning the surface to remove organic contaminants and enhance surface activity. Then, a chemical gas containing negatively charged groups, such as acrylic acid, methacrylic acid, or vinyl sulfonate, is selected and introduced into the plasma reaction chamber through an inlet system. Subsequently, under the excitation of the radio frequency power supply, the gas molecules are activated to form plasma. The negatively charged groups are deposited on or near the surface of the nonwoven fabric through surface reactions and interactions. Finally, after deposition is complete, gas introduction is stopped, and the chamber is rinsed with an inert gas to remove any possible gas residue.

[0035] The method of using the self-repelling cement particle permeable concrete formwork cloth of Examples 1 and 2 is as follows: Adhere the base layer 3 to the concrete steel formwork, ensuring that it is flat and without dead corners; pour fresh concrete, with the repelling layer 1 in contact with the fresh concrete; turn on the vibrator and vibrate the concrete evenly; after the concrete has cured for 1 day, peel the self-repelling cement particle permeable concrete formwork cloth from the hardened concrete surface, let it dry, and store it for the next use.

Claims

1. A permeable concrete formwork fabric with self-repelling cement particles, characterized in that, It includes a repellent layer, a water-conducting layer, and a substrate layer; the repellent layer is an anionic polymer film or anionic modified nonwoven fabric; the water-conducting layer consists of an upper layer, a middle layer, and a lower layer, with the pore size gradually increasing from top to bottom; the repellent layer is connected to the upper layer of the water-conducting layer, and the lower layer of the water-conducting layer is connected to the substrate layer.

2. The permeable concrete formwork fabric with self-repelling cement particles according to claim 1, characterized in that, The repulsion layer has a pore size of 0.1~1μm and a thickness of 0.1~0.3mm.

3. The permeable concrete formwork fabric with self-repelling cement particles according to claim 1, characterized in that: The anionic polymer film is one of polyacrylic acid, sodium polystyrene sulfonate, polyvinyl alcohol sulfonic acid, and sulfonated polyether sulfone.

4. The permeable concrete formwork fabric with self-repelling cement particles according to claim 1, characterized in that: The upper layer of the water-conducting layer has a pore size of 1~3μm and a thickness of 0.2~0.4mm; the middle layer of the water-conducting layer has a pore size of 3~6μm and a thickness of 0.3~0.5mm; and the lower layer of the water-conducting layer has a pore size of 6~10μm and a thickness of 0.3~0.5mm.

5. The permeable concrete formwork fabric with self-repelling cement particles according to claim 1, characterized in that: The repellent layer and the upper layer of the water-conducting layer are bonded together by ultrasonic welding; the upper, middle and lower layers of the water-conducting layer are connected by hot-press bonding; the lower layer of the water-conducting layer is connected to the substrate layer by hot-press bonding.

6. The permeable concrete formwork fabric with self-repelling cement particles according to claim 1, characterized in that: The base layer is made of polyethylene or polypropylene fiber with a thickness of 0.2~0.5mm.

7. The permeable concrete formwork fabric with self-repelling cement particles according to claim 1, characterized in that: The upper layer of the water-conducting layer is made of highly absorbent cellulose fiber, while the middle and lower layers are made of porous polyurethane foam.

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