CN112094090A

CN112094090A - High-performance RPC cover plate for sewage well and preparation method thereof

Info

Publication number: CN112094090A
Application number: CN202010998508.0A
Authority: CN
Inventors: 容七英
Original assignee: Jiangxi Longzheng Technology Development Co Ltd
Current assignee: Jiangxi Longzheng Technology Development Co Ltd
Priority date: 2020-09-21
Filing date: 2020-09-21
Publication date: 2020-12-18

Abstract

The invention relates to a high-performance RPC cover plate for a sewage well, which is prepared from the following raw materials in parts by weight: 200 parts of cement, 300 parts of quartz sand, 20-40 parts of functional toughening powder, 10-30 parts of modified steel fiber, 50-70 parts of mineral admixture, 1-5 parts of composite water reducer and 60-90 parts of water. The mineral admixture is introduced into the material system of the RPC cover plate, the mineral admixture, cement and quartz sand can jointly exert high-efficiency bonding performance and reduce economic cost, the strength of the final RPC cover plate can be effectively improved by using the modified steel fiber, in addition, the toughness of the RPC cover plate can be improved by using the functional toughening powder, the breaking strength and the fracture toughness of the RPC cover plate can be improved, the damage of internal unbalanced stress of the RPC cover plate on the cover plate body due to long-time use can be effectively resisted, the occurrence of cracks caused by uneven stress in the cover plate body can be effectively inhibited, and the normal service life of the cover plate is greatly prolonged.

Description

High-performance RPC cover plate for sewage well and preparation method thereof

Technical Field

The invention belongs to the technical field of concrete materials, and relates to a high-performance RPC cover plate for a sewage well and a preparation method thereof.

Background

As is well known, RPC, i.e., reactive powder concrete, is a cement-based material that is developed by using conventional cement and other materials in the middle of the 90 s after high-strength and high-performance concrete, and is a high-performance concrete compounded by a DSP material and a fiber-reinforced material. The plate made of the RPC material has excellent mechanical strength, stable performance and relatively long service life, and is widely applied to building engineering, such as power plants, highways, intercity railways, subway bridges and tunnels, trench cover plates and cable duct cover plates of municipal engineering, and steel structures of the building engineering, inner wall enclosures of wooden buildings, floor clapboards, sound-absorbing boards of sports, theaters and meeting rooms, stair pedals and the like.

However, although the existing RPC cover plate for sewage wells has high strength and high stability, the existing RPC cover plate has high brittleness, and is quite unfavorable for resisting impact load and bearing vibration, i.e. when the RPC cover plate is impacted, the RPC cover plate is easily damaged, and the RPC cover plate is a main cause of fracture. In addition, the corrosion resistance and wear resistance of the existing RPC cover plate are also to be further improved.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide the high-performance RPC cover plate for the sewage well, which has the advantages of good wear resistance and corrosion resistance, high strength, better toughness, long service life and good volume stability.

The invention also aims to provide a preparation method of the high-performance RPC cover plate for the sewage well.

The purpose of the invention can be realized by the following technical scheme:

according to one aspect of the invention, the high-performance RPC cover plate for the sewage well is prepared from the following raw materials in parts by weight: 200 parts of cement, 300 parts of quartz sand, 20-40 parts of functional toughening powder, 30-50 parts of modified steel fiber, 50-70 parts of mineral admixture, 1-5 parts of composite water reducer and 60-90 parts of water.

As a preferred technical scheme, the functional toughening powder is prepared from the following raw materials in parts by weight: 60-80 parts of SEBS thermoplastic elastomer, 5-20 parts of organic fluororesin, 10-20 parts of maleic anhydride grafted ethylene propylene diene monomer, 0.1-1 part of organic peroxide, 1-5 parts of expandable graphite, 6-12 parts of modified rice hull ash, 1-3 parts of calcium linoleate soap and 60-70 parts of paraffin oil.

As a preferable technical scheme, the organic fluororesin is one selected from hexafluorobutyl acrylate, hexafluoroisopropyl acrylate or hexafluoroisopropyl methacrylate, the grafting ratio of the maleic anhydride grafted ethylene propylene diene monomer is 1.2-1.8%, the organic peroxide is tert-butyl peroxybenzoate, the carbon content of the expandable graphite is more than or equal to 97%, and the particle size is 0.1-0.2 mm.

As a preferred technical scheme, the preparation method of the modified rice hull ash comprises the following steps:

step 1: incinerating the rice hulls at the temperature of 700-;

step 2: uniformly mixing the rice hull ash powder with absolute ethyl alcohol to prepare a mixed solution of the rice hull ash powder and the absolute ethyl alcohol;

and step 3: adding hydroxymethyl cellulose, a silane coupling agent and calcium sulfate whiskers into the mixed solution, adjusting the pH value of the solution to 5 by using dilute nitric acid, reacting for 4-6 hours at 85 ℃, cooling, filtering, washing, drying to constant weight, grinding, and sieving with a 650-mesh sieve to obtain the modified rice hull ash.

As a preferable technical scheme, the usage relationship between the rice hull ash powder and the absolute ethyl alcohol in the step 2 is as follows: 5-10 g of rice hull ash powder is added to each 100 mL of absolute ethyl alcohol.

Preferably, in step 3, the amount of the hydroxymethyl cellulose is 2-8% of the mass of the rice hull ash powder, the amount of the silane coupling agent is 0.5-1.2% of the mass of the rice hull ash powder, and the amount of the calcium sulfate whisker is 1-3% of the mass of the rice hull ash powder.

Further, the silane coupling agent may be selected from one of commercially available KH-550, KH-560 or KH-570.

As a preferred technical scheme, the preparation method of the functional toughening powder material comprises the following steps: mixing SEBS thermoplastic elastomer and paraffin oil according to parts by weight, standing for 24 hours to fully swell the SEBS thermoplastic elastomer, adding the swelled SEBS thermoplastic elastomer on an open plasticator with a double-roller temperature of 160-170 ℃, adding organic fluorine resin and maleic anhydride grafted ethylene propylene diene monomer according to parts by weight for mixing, after uniform plasticization, adding organic peroxide and calcium linoleate soap according to parts by weight for mixing for 10 minutes, adding modified rice hull ash and expandable graphite according to parts by weight, continuing mixing for 20 minutes, discharging sheets after uniform mixing, performing hot pressing at 180 ℃, then performing cold pressing at room temperature to discharge sheets, and then dehumidifying, pelletizing and drying to obtain the functional toughening powder.

As a preferred technical scheme, the modified steel fiber is a polytetrafluoroethylene modified steel fiber and is prepared by the following method: uniformly mixing carbon fibers, steel fibers and polytetrafluoroethylene according to the mass ratio of 1-2:3-5:100, sintering at the temperature of 120-150 ℃ for 10-30 minutes, cooling and crushing into particles with the diameter of 0.15-0.2mm and the length of 3-12 mm.

As a preferable technical scheme, the cement is 52.5-grade ordinary portland cement, the particle size of the quartz sand is less than or equal to 2mm, and SiO is adopted₂The content is more than or equal to 98 percent, the mud content is less than or equal to 0.5 percent, the mineral admixture comprises at least one of silica fume, blast furnace slag powder and superfine metakaolin, and the specific surface area of the mineral admixture is more than or equal to 2000m²And/kg, the composite water reducing agent is prepared by mixing a naphthalene water reducing agent, a melamine water reducing agent and a polycarboxylic acid water reducing agent according to the mass ratio of 1:1: 3.

According to another aspect of the invention, a method for preparing a high-performance RPC cover plate for a sewage well is provided, which comprises the following steps:

(1) adding cement, quartz sand, functional toughening powder, modified steel fiber, mineral admixture, composite water reducer and water into a stirrer according to the parts by weight, and uniformly stirring and mixing to obtain concrete slurry;

(2) placing the finished mould on a vibration table, opening the vibration table, pouring the stirred concrete slurry into the mould until the mould is completely formed, and thus obtaining the initially-formed RPC cover plate;

(3) and (3) placing the preliminarily molded RPC cover plate into a curing chamber for curing to obtain an initially solidified RPC cover plate, separating the initially solidified RPC cover plate from the mold to obtain a demolded RPC cover plate, and then sending the demolded RPC cover plate into the curing chamber for steam curing at the curing temperature of 80-90 ℃ for 2 days.

Compared with the prior art, the invention has the following characteristics:

1) in the functional toughening powder adopted by the raw material components of the RPC cover plate, the SEBS thermoplastic elastomer is used as a base material, the organic fluororesin is introduced, and the maleic anhydride grafted ethylene propylene diene monomer is used as a compatilizer, so that the interface acting force of the organic fluororesin and the SEBS thermoplastic elastomer can be effectively improved, the compatibility of the organic fluororesin and the SEBS thermoplastic elastomer is improved, and the flame retardance, the dirt resistance and the corrosion resistance of the functional toughening powder can be effectively improved on the premise of ensuring that the final functional toughening powder has good flexibility;

2) modified rice hull ash is introduced into the adopted functional toughening powder, and the modified rice hull ash is obtained by adopting a silane coupling agent to carry out surface modification on the rice hull ash, so that the modified rice hull ash is favorable for forming stronger interaction with a matrix material and improving the compatibility of the modified rice hull ash and the matrix material, is favorable for promoting the dispersibility of the expandable graphite in the matrix material, and can effectively improve the frost resistance and the heat resistance stability of the final functional toughening powder by mutually playing a synergistic effect;

3) according to the RPC cover plate, the modified steel fiber is adopted in the raw material components, polytetrafluoroethylene is coated on the steel fiber, and then sintering treatment is carried out, so that the prepared modified steel fiber has good adhesion with cement, quartz sand and mineral admixture, the hardness of the material system is enhanced, the bending strength of the material system can be improved, and the problem that cracks or fissures are easy to occur on the surface due to sudden change of external temperature can be effectively avoided;

4) the mineral admixture is introduced into the material system of the RPC cover plate, the mineral admixture, cement and quartz sand can jointly exert high-efficiency bonding performance and reduce economic cost, the strength of the final RPC cover plate can be effectively improved by using the modified steel fiber, in addition, the toughness of the RPC cover plate can be improved by using the functional toughening powder, the breaking strength and the fracture toughness of the RPC cover plate can be improved, the damage of internal unbalanced stress of the RPC cover plate on the cover plate body due to long-time use can be effectively resisted, the occurrence of cracks caused by uneven stress in the cover plate body can be effectively inhibited, and the normal service life of the cover plate is greatly prolonged.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to specific embodiments, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed embodiment and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments. All other embodiments obtained by a person skilled in the art without making any inventive step are within the scope of protection of the present invention.

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein. As used herein, the term "about" when used to modify a numerical value means within + -5% of the error margin measured for that value.

The technical scheme of the invention is further illustrated by the following specific examples, and the raw materials used in the invention are all commercial products unless otherwise specified.

The following table 1 shows the raw material components and the weight part contents thereof of the RPC cover sheets in examples 1 to 5 and comparative examples 1 to 2.

TABLE 1 formulation of raw Material Components for RPC cover plates in examples 1-5 and comparative examples 1-2

The cement used in examples 1 to 5 and comparative examples 1 to 2 in Table 1 was a Portland cement of grade 52.5, the quartz sand used had a particle size of 2mm or less, and SiO₂The content is more than or equal to 98 percent, the mud content is less than or equal to 0.5 percent, and the adopted composite water reducing agent is formed by mixing a naphthalene water reducing agent, a melamine water reducing agent and a polycarboxylic acid water reducing agent according to the mass ratio of 1:1: 3.

The modified steel fiber used in example 1 in table 1 is a polytetrafluoroethylene modified steel fiber prepared by the following method: uniformly mixing carbon fibers, steel fibers and polytetrafluoroethylene according to a mass ratio of 1:3:100, sintering at 120 ℃ for 30 minutes, cooling, and crushing into particles with the diameter of 0.2mm and the length of 12 mm;

the modified steel fiber used in example 2 is a polytetrafluoroethylene-modified steel fiber, and is prepared by the following method: uniformly mixing carbon fibers, steel fibers and polytetrafluoroethylene according to a mass ratio of 2:5:100, sintering at 140 ℃ for 30 minutes, cooling, and crushing into particles with the diameter of 0.2mm and the length of 10 mm;

the modified steel fibers used in examples 3-5 were polytetrafluoroethylene modified steel fibers prepared by the following method: uniformly mixing carbon fibers, steel fibers and polytetrafluoroethylene according to the mass ratio of 1:4:100, sintering at 150 ℃ for 10 minutes, cooling, and crushing into particles with the diameter of 0.15mm and the length of 3 mm.

The mineral admixtures used in examples 1-2 of Table 1 had specific surface areas of 2000m or more²/kg of ultrafine metakaolin; the mineral admixture used in the example 3 and the comparative examples 1-2 is formed by mixing silica fume, blast furnace slag powder and superfine metakaolin according to the mass ratio of 1:3:1, and the specific surface area is more than or equal to 2000m²Per kg; example 4 the mineral admixture used was a mineral admixture having a specific surface area of 2000m or more²/kg of blast furnace slag powder; example 5 the mineral admixture used was a mineral admixture having a specific surface area of 2000m or more²Silica fume per kg.

The following table 2 shows the formulations of the functional toughening powder used in examples 1-5.

TABLE 2 formulation of functional toughening powders used in examples 1-5

In Table 2, the maleic anhydride-grafted ethylene-propylene-diene rubber used in example 1 had a grafting rate of 1.2%, the maleic anhydride-grafted ethylene-propylene-diene rubber used in example 2 had a grafting rate of 1.8%, the maleic anhydride-grafted ethylene-propylene-diene rubber used in example 3 had a grafting rate of 1.3%, and the maleic anhydride-grafted ethylene-propylene-diene rubbers used in examples 4 and 5 had a grafting rate of 1.5%.

The organic peroxide used in examples 1-5 of Table 2 was t-butyl peroxybenzoate.

In Table 2, the expandable graphite used in examples 1 to 3 had a carbon content of not less than 97% and a particle size of 0.1mm, and the expandable graphite used in examples 4 to 5 had a carbon content of not less than 97% and a particle size of 0.2 mm.

The modified rice hull ash used in examples 1-2 of Table 2 was prepared as follows:

step 1: incinerating rice hulls at 700 ℃, collecting incineration residues, grinding by using a ball mill, and then sieving by using a 900-mesh sieve to obtain rice hull ash powder;

step 2: uniformly mixing the rice hull ash powder with absolute ethyl alcohol to prepare a mixed solution of the rice hull ash powder and the absolute ethyl alcohol, wherein the dosage relationship of the rice hull ash powder and the absolute ethyl alcohol is as follows: adding 5g of rice hull ash powder into every 100 mL of absolute ethyl alcohol;

and step 3: adding hydroxymethyl cellulose, a silane coupling agent KH-550 and calcium sulfate whiskers into the mixed solution, wherein the dosage of the hydroxymethyl cellulose is 8% of the mass of the rice hull ash powder, the dosage of the silane coupling agent KH-550 is 1.2% of the mass of the rice hull ash powder, and the dosage of the calcium sulfate whiskers is 3% of the mass of the rice hull ash powder, then adopting dilute nitric acid to adjust the pH of the solution to 5, reacting for 6 hours at 85 ℃, cooling, filtering, washing, drying to constant weight, and sieving with a 650-mesh sieve after grinding to obtain the rice hull ash.

The modified rice hull ash used in examples 3-4 was prepared as follows:

step 1: incinerating rice hulls at 800 ℃, collecting incineration residues, grinding by using a ball mill, and then sieving by using a 900-mesh sieve to obtain rice hull ash powder;

step 2: uniformly mixing the rice hull ash powder with absolute ethyl alcohol to prepare a mixed solution of the rice hull ash powder and the absolute ethyl alcohol, wherein the dosage relationship of the rice hull ash powder and the absolute ethyl alcohol is as follows: adding 10g of rice hull ash powder into every 100 mL of absolute ethyl alcohol;

and step 3: adding hydroxymethyl cellulose, a silane coupling agent KH-560 and calcium sulfate whiskers into the mixed solution, wherein the dosage of the hydroxymethyl cellulose is 5% of the mass of the rice hull ash powder, the dosage of the silane coupling agent KH-550 is 0.8% of the mass of the rice hull ash powder, and the dosage of the calcium sulfate whiskers is 1.3% of the mass of the rice hull ash powder, then adopting dilute nitric acid to adjust the pH of the solution to 5, reacting for 5 hours at 85 ℃, cooling, filtering, washing, drying to constant weight, and sieving with a 650-mesh sieve after grinding.

The modified rice hull ash used in example 5 was prepared as follows:

step 1: incinerating rice hulls at 780 ℃, collecting incineration residues, grinding by using a ball mill, and then sieving by using a 900-mesh sieve to obtain rice hull ash powder;

step 2: uniformly mixing the rice hull ash powder with absolute ethyl alcohol to prepare a mixed solution of the rice hull ash powder and the absolute ethyl alcohol, wherein the dosage relationship of the rice hull ash powder and the absolute ethyl alcohol is as follows: adding 7g of rice hull ash powder into every 100 mL of absolute ethyl alcohol;

and step 3: adding hydroxymethyl cellulose, a silane coupling agent KH-570 and calcium sulfate whiskers into the mixed solution, wherein the dosage of the hydroxymethyl cellulose is 2% of the mass of the rice hull ash powder, the dosage of the silane coupling agent KH-550 is 0.5% of the mass of the rice hull ash powder, and the dosage of the calcium sulfate whiskers is 1% of the mass of the rice hull ash powder, then adopting dilute nitric acid to adjust the pH of the solution to 5, reacting for 4 hours at 85 ℃, cooling, filtering, washing, drying to constant weight, and sieving with a 650-mesh sieve after grinding to obtain the rice hull ash powder.

The preparation method of the functional toughening powder used in examples 1 to 5 was as follows:

step i): mixing the SEBS thermoplastic elastomer and paraffin oil according to the weight part, and standing for 24 hours to fully swell the SEBS thermoplastic elastomer;

step ii): adding the swelled SEBS thermoplastic elastomer on an open plasticator with a double-roller temperature of 160-170 ℃, adding organic fluorine resin and maleic anhydride grafted ethylene propylene diene monomer according to parts by weight for mixing, after plasticizing uniformly, adding organic peroxide and calcium linoleate soap according to parts by weight for mixing for 10 minutes, adding modified rice hull ash and expandable graphite according to parts by weight, continuing mixing for 20 minutes, discharging the mixture after mixing uniformly, carrying out hot pressing at 180 ℃, then carrying out cold pressing at room temperature for discharging the mixture, and dehumidifying, granulating and drying to obtain the functional toughening powder.

In step ii) above, example 1 was set to 160 ℃, example 2 was set to 170 ℃, example 3 was set to 162 ℃, example 4 was set to 168 ℃ and example 5 was set to 165 ℃ for the two roll temperature of the open mill.

The raw material formulation materials of examples 1-5 were made into RPC cover plates using the following method:

(1) adding cement, quartz sand, functional toughening powder, modified steel fiber, mineral admixture, composite water reducer and water into a stirrer in parts by weight, and uniformly stirring and mixing to obtain concrete slurry;

Comparative examples 1-2 RPC cover plates were made using the same procedure as described above.

The following table 3 shows the performance test results of the RPC cover sheets manufactured using the raw material component formulations of examples 1-5 and comparative examples 1-2.

TABLE 3 Performance test results of RPC cover sheets made from the stock component formulations of examples 1-5 and comparative examples 1-2

。

The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.

Claims

1. The high-performance RPC cover plate for the sewage well is characterized by being prepared from the following raw materials in parts by weight: 200 parts of cement, 300 parts of quartz sand, 20-40 parts of functional toughening powder, 30-50 parts of modified steel fiber, 50-70 parts of mineral admixture, 1-5 parts of composite water reducer and 60-90 parts of water.

2. The high-performance RPC cover plate for the sewage well according to claim 1, wherein the functional toughening powder is prepared from the following raw materials in parts by weight: 60-80 parts of SEBS thermoplastic elastomer, 5-20 parts of organic fluororesin, 10-20 parts of maleic anhydride grafted ethylene propylene diene monomer, 0.1-1 part of organic peroxide, 1-5 parts of expandable graphite, 6-12 parts of modified rice hull ash, 1-3 parts of calcium linoleate soap and 60-70 parts of paraffin oil.

3. The high-performance RPC cover plate for the sewage well according to claim 2, wherein the organic fluorine resin is one selected from hexafluorobutyl acrylate, hexafluoroisopropyl acrylate or hexafluoroisopropyl methacrylate, the grafting ratio of the maleic anhydride grafted ethylene propylene diene monomer rubber is 1.2-1.8%, the organic peroxide is tert-butyl peroxybenzoate, the carbon content of the expandable graphite is more than or equal to 97%, and the particle size is 0.1-0.2 mm.

4. The high-performance RPC cover plate for the sewage well according to claim 2, wherein the preparation method of the modified rice hull ash is as follows:

step 1: incinerating the rice hulls at the temperature of 700-;

5. The high-performance RPC cover plate for the sewage well according to claim 4, wherein the rice hull ash powder and the absolute ethyl alcohol in the step 2 are in the following dosage relationship: 5-10 g of rice hull ash powder is added to each 100 mL of absolute ethyl alcohol.

6. The high-performance RPC cover plate for the sewage well according to claim 4, wherein in step 3, the amount of the hydroxymethyl cellulose is 2-8% of the mass of the rice hull ash powder, the amount of the silane coupling agent is 0.5-1.2% of the mass of the rice hull ash powder, and the amount of the calcium sulfate whiskers is 1-3% of the mass of the rice hull ash powder.

7. The high-performance RPC cover plate for the sewage well according to claim 2, wherein the preparation method of the functional toughening powder material comprises the following steps: mixing SEBS thermoplastic elastomer and paraffin oil according to parts by weight, standing for 24 hours to fully swell the SEBS thermoplastic elastomer, adding the swelled SEBS thermoplastic elastomer on an open plasticator with a double-roller temperature of 160-170 ℃, adding organic fluorine resin and maleic anhydride grafted ethylene propylene diene monomer according to parts by weight for mixing, after uniform plasticization, adding organic peroxide and calcium linoleate soap according to parts by weight for mixing for 10 minutes, adding modified rice hull ash and expandable graphite according to parts by weight, continuing mixing for 20 minutes, discharging sheets after uniform mixing, performing hot pressing at 180 ℃, then performing cold pressing at room temperature to discharge sheets, and then dehumidifying, pelletizing and drying to obtain the functional toughening powder.

8. The high-performance RPC cover plate for the sewage well according to claim 1, wherein the modified steel fiber is a polytetrafluoroethylene-modified steel fiber, and is prepared by the following method: uniformly mixing carbon fibers, steel fibers and polytetrafluoroethylene according to the mass ratio of 1-2:3-5:100, sintering at the temperature of 120-150 ℃ for 10-30 minutes, cooling and crushing into particles with the diameter of 0.15-0.2mm and the length of 3-12 mm.

9. The high-performance RPC cover plate for the sewage well according to claim 1, wherein the cement is 52.5-grade ordinary portland cement, the particle size of the quartz sand is less than or equal to 2mm, and SiO is₂The content is more than or equal to 98 percent, the mud content is less than or equal to 0.5 percent, the mineral admixture comprises at least one of silica fume, blast furnace slag powder and superfine metakaolin, and the specific surface area of the mineral admixture is more than or equal to 2000m²And/kg, the composite water reducing agent is prepared by mixing a naphthalene water reducing agent, a melamine water reducing agent and a polycarboxylic acid water reducing agent according to the mass ratio of 1:1: 3.

10. The method for preparing a high performance RPC cover plate for a sewage well according to any of claims 1 to 9, wherein the method comprises the following steps: