Tunnel maintenance path RPC cover plate and preparation method and application thereof

Abstract

The invention provides a tunnel maintenance path RPC cover plate and a preparation method and application thereof, and relates to the technical field of highway and municipal tunnel engineering, the RPC cover plate matrix comprises the following components by weight: 750-850 parts of cement, 110-220 parts of fly ash, 120-220 parts of silica fume, 1000-1200 parts of fine aggregate, 10-80 parts of an additive, 130-160 parts of water, and 80-120 parts of fiber; the fibers comprise short-end hook steel fibers and polypropylene fibers; the mass ratio of the short-end hook steel fibers in the matrix is 0.6%-2%, and the mass ratio of the polypropylene fibers in the matrix is 0.1%-0.2%. The RPC cover plate for the tunnel maintenance road has the characteristics of high strength, high durability and small thickness, and is high in fracture resistance, low in manufacturing cost, easier to shape and attractive in appearance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of highway and municipal tunnel engineering, and particularly relates to a tunnel maintenance access RPC cover plate and a preparation method and application thereof. BACKGROUND

[0002] At present, ordinary concrete cover plates are mainly used for the cover plates of maintenance accesses, inspection wells and sidewalks on both sides of highway and municipal road tunnels, and the main reason is that ordinary reinforced concrete cover plates are convenient to construct, can be directly produced on site, have low cost and certain economy. However, it is found in the tunnel operation process that the fracture rate and damage rate of ordinary reinforced concrete cover plates are extremely high, mainly because the ordinary concrete has low bending strength, poor durability and insufficient toughness, and in addition, the cover plates are easily broken due to the frequent turning of the cover plates for cable trough maintenance. In addition, the ordinary concrete cover plates have large self-weight and are inconvenient to transport, install and move. With the gradual development of highway construction, operation and maintenance into the high-quality development stage, engineering construction pays more attention to quality, efficiency, safety and environmental protection, and therefore the demand for high-performance, high-quality and lightweight cover plates is increasing.

[0003] In order to solve the above problems, researchers begin to use reactive powder concrete to produce cover plates, and the RPC cover plate is a new generation of concrete cover plate prepared based on fiber reinforced reactive powder concrete. The RPC material is prepared by optimizing the grading of micron-sized materials to achieve maximum density at an extremely low water-binder ratio, and by mixing high-activity nanomaterials, and is a new inorganic composite material combined with ultra-fine particle dense material and fiber reinforcement technology. Due to the ultra-high tensile performance of RPC and the durability brought by high density, an excellent performance ultra-thin cover plate product is prepared.

[0004] In order to improve the compactness and bending performance of the RPC cover plate, some researchers add basalt fiber composite bars to the interior of the RPC cover plate matrix to improve the bending performance of the cover plate, use waste steel fibers to replace ordinary steel fibers, and optimize the mix proportion to improve the strength. However, the basalt fiber composite bar has low elastic modulus, and has limited effect on improving the bending strength of the cover plate, and the basalt fiber composite bar has light weight, and the composite bar is prone to floating in the actual construction process, and the position of the composite bar in the cover plate cannot be better controlled; at the same time, the basalt fiber composite bar has high price, which will increase the cost of the cover plate; the waste steel fiber is beneficial to reducing the cost, but is prone to knotting and difficult to stir uniformly in the stirring process.

[0005] Therefore, the present application is proposed. SUMMARY

[0006] One of the purposes of the present application is to provide a tunnel maintenance path RPC cover plate, which has the characteristics of high strength, high durability and thin thickness, not only strong bending resistance, but also low cover plate cost, and is easier to shape and has an attractive appearance.

[0007] The second purpose of the present application is to provide a preparation method of the tunnel maintenance path RPC cover plate, which is simple, efficient and has a high success rate, and is suitable for factory production.

[0008] The third purpose of the present application is to provide an application of the tunnel maintenance path RPC cover plate, which can achieve outstanding application effects.

[0009] In order to achieve the above-mentioned purposes of the present application, the following technical solutions are adopted:

[0010] In a first aspect, a tunnel maintenance path RPC cover plate, the RPC cover plate base body comprises the following components by weight fraction:

[0011] Cement 750-850 parts, fly ash 110-220 parts, silica ash 120-220 parts, fine aggregate 1000-1200 parts, additive 10-80 parts, water 130-160 parts, and fiber 80-120 parts;

[0012] The fiber comprises short-end hook steel fiber and polypropylene fiber;

[0013] The mass fraction of the short-end hook steel fiber in the base body is 0.6%-2%, and the mass fraction of the polypropylene fiber in the base body is 0.1%-0.2%.

[0014] Further, the RPC cover plate is provided with an auxiliary component;

[0015] The auxiliary component comprises a supporting leg, a non-slip pattern and a waist pinch, so as to facilitate the replacement of ordinary concrete cover plates during tunnel operation.

[0016] Further, the supporting leg is an adjustable height supporting leg;

[0017] Preferably, the non-slip pattern comprises at least one of a circle, a square, a cobblestone shape and a flower shape;

[0018] Preferably, the waist pinch is arranged at the middle line position of the cover plate body.

[0019] Further, the RPC cover plate base body is provided with a steel mesh;

[0020] The steel mesh comprises transverse steel bars and longitudinal steel bars, so as to improve the bending resistance of the RPC cover plate.

[0021] Further, the transverse steel bars are smooth steel bars;

[0022] Preferably, the transverse steel bars include at least one of a smooth steel bar with a diameter of φ5mm and a smooth steel bar with a diameter of φ6mm;

[0023] Preferably, the length of the transverse steel bars is 70mm-100mm;

[0024] Preferably, the longitudinal steel bars are smooth steel bars;

[0025] Preferably, the longitudinal steel bars include at least one of a smooth steel bar with a diameter of φ5mm and a smooth steel bar with a diameter of φ6mm;

[0026] Preferably, the length of the longitudinal steel bars is 40mm-50mm.

[0027] Further, the cement includes ordinary portland cement of grade 52.5;

[0028] Preferably, the fly ash includes fly ash of grade I;

[0029] Preferably, the particle size of the fly ash is not greater than 80μm;

[0030] Preferably, the silica fume includes semi-encrypted silica fume;

[0031] Preferably, the silica content in the semi-encrypted silica fume is not less than 92%;

[0032] Preferably, the fine aggregate includes machine-made quartz sand.

[0033] Further, the admixture includes at least one of a water reducing agent and a pigment;

[0034] Preferably, the water reducing agent includes a high-efficiency polycarboxylic liquid water reducing agent;

[0035] Preferably, the pigment includes at least one of an inorganic pigment and an organic pigment.

[0036] In a second aspect, a method for preparing the tunnel access RPC cover plate according to any one of the preceding aspects includes the following steps:

[0037] After mixing the components in proportion, pouring is performed to obtain the RPC cover plate.

[0038] Further, the method for preparing further includes the following steps:

[0039] After pouring, vibrating is performed, and during the vibrating process, the steel bar mesh is arranged in the slurry, and steaming is performed to obtain the RPC cover plate.

[0040] Thirdly, the application of the tunnel access RPC cover plate in any one of the above aspects in municipal tunnel access, highway tunnel access, inspection well, sidewalk and subway evacuation passage.

[0041] Compared with the prior art, the application has at least the following beneficial effects:

[0042] The tunnel access RPC cover plate provided by the application uses mixed short-end hook steel fibers and polypropylene fibers to replace steel fibers, which improves the folding resistance of the cover plate and reduces the cost of the cover plate; under the action of the components and their proportions, the RPC cover plate has the characteristics of high strength, high durability and thin thickness, is easy to shape and has an attractive appearance.

[0043] The preparation method of the tunnel access RPC cover plate provided by the application is simple, efficient and has a high success rate, and is suitable for factory production.

[0044] The application of the tunnel access RPC cover plate provided by the application can achieve outstanding application effects. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the specific embodiments of the application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the description of the specific embodiments or the prior art. Obviously, the drawings described below are some embodiments of the application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0046] Figure 1 The structural schematic diagram of the RPC cover plate provided by one embodiment of the application is shown in the figure.

[0047] Figure 2 The schematic diagram of the RPC cover plate provided by one embodiment of the application is shown in the figure.

[0048] Figure legend: 1-RPC cover plate base body; 2-supporting foot; 3-anti-skid pattern; 4-waist pinch; 5-transverse steel bar; 6-longitudinal steel bar. DETAILED DESCRIPTION

[0049] The technical solutions of the application will be described in detail below with reference to the embodiments. Obviously, the described embodiments are only some of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0050] According to the first aspect of the application, a tunnel access RPC cover plate is provided, and the RPC cover plate base body comprises the following components by weight fraction:

[0051] cement 750-850 parts, fly ash 110-220 parts, silica ash 120-220 parts, fine aggregate 1000-1200 parts, additive 10-80 parts, water 130-160 parts, and fiber 80-120 parts;

[0052] The fiber includes short-end hook steel fiber and polypropylene fiber, and the weight ratio of the short-end hook steel fiber and the polypropylene fiber can be 100:1-2, and the typical but non-limiting weight ratio is, for example, 100:1, 100:1.1, 100:1.2, 100:1.3, 100:1.4, 100:1.5, 100:1.6, 100:1.7, 100:1.8, 100:1.9, 100:2, and can be preferably 100:1.2-1.5.

[0053] The mass percentage of the short-end hook steel fiber in the matrix can be 0.6%-2%, and the typical but non-limiting mass percentage is, for example, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, and can be preferably 0.9%-1.5%.

[0054] The length of the short-end hook steel fiber can be 15-20 mm, and the diameter can be 0.2-0.3 mm.

[0055] The mass percentage of the polypropylene fiber in the matrix can be 0.1%-0.2%, and the typical but non-limiting mass percentage is, for example, 0.1%, 0.12%, 0.14%, 0.16%, 0.18%, 0.2%, and can be preferably 0.12%-0.16%.

[0056] The length of the polypropylene fiber can be 3-10 mm, and the diameter can be 10-50 μm.

[0057] The application uses mixed short-end hook steel fiber and polypropylene fiber to replace steel fiber, which improves the folding resistance of the cover plate and reduces the cost of the cover plate.

[0058] In the application, the typical but non-limiting weight parts of the cement are, for example, 750 parts, 760 parts, 770 parts, 780 parts, 790 parts, 800 parts, 810 parts, 820 parts, 830 parts, 840 parts, 850 parts, and can be preferably 760-820 parts, and more preferably 770-800 parts, and preferably 52.5-grade ordinary portland cement.

[0059] In the present application, the typical but non-limiting weight fraction of fly ash is, for example, 110 parts, 130 parts, 150 parts, 180 parts, 200 parts, 220 parts, which can be preferably 110 parts to 180 parts, preferably Grade I fly ash, and the particle size of fly ash is not greater than 80 microns.

[0060] In the present application, the typical but non-limiting weight fraction of silica ash is, for example, 120 parts, 130 parts, 140 parts, 150 parts, 160 parts, 170 parts, 180 parts, 190 parts, 200 parts, 210 parts, 220 parts, which can be preferably 150 parts to 200 parts, more preferably 170 parts to 190 parts, preferably semi-encrypted silica ash, which is easier to mix uniformly during concrete mixing, and the particle morphology of semi-encrypted silica ash can adsorb free water, reduce concrete bleeding and segregation, and the silica content in semi-encrypted silica ash is not less than 92%.

[0061] In the present application, the typical but non-limiting weight fraction of fine aggregate is, for example, 1000 parts, 1050 parts, 1100 parts, 1200 parts, which can be preferably 1050 parts to 1100 parts, preferably machine-made quartz sand, which is preferably made of natural quartzite; the fine aggregate includes coarse sand, medium sand and fine sand, wherein the weight fraction of the coarse sand component is preferably 250 parts to 290 parts, and the particle size is preferably 0.1 mm to 0.3 mm, the weight fraction of the medium sand component is preferably 500 parts to 580 parts, and the particle size is preferably 0.3 mm to 0.9 mm, and the weight fraction of the fine sand component is preferably 260 parts to 300 parts, and the particle size is preferably 0.9 mm to 5 mm.

[0062] In the present application, the typical but non-limiting weight fraction of the additive is, for example, 10 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, and the additive includes but is not limited to at least one of water reducing agent and pigment; wherein the weight fraction of the water reducing agent can be 10 parts to 20 parts, preferably high-efficiency polycarboxylic acid liquid water reducing agent; the weight fraction of the pigment can be 10 parts to 60 parts, preferably inorganic pigment or organic pigment, more preferably inorganic pigment, and the inorganic pigment includes but is not limited to iron oxide, chromium oxide, carbon black and cobalt blue, all of which are in the form of powder.

[0063] The type and amount of pigment are adjusted according to the color requirements of the cover plate, and the color of the cover plate can be adjusted by adding pigment to make various colored cover plates, which are more beautiful in shape.

[0064] The typical but non-limiting weight fraction of water is, for example, 130 parts, 140 parts, 150 parts, 160 parts; and the typical but non-limiting weight fraction of fiber is, for example, 80 parts, 90 parts, 100 parts, 110 parts, 120 parts.

[0065] In summary, the RPC cover plate has the characteristics of high strength, high durability and thin thickness under the action of the components and the proportioning thereof, is easy to model and has an attractive appearance.

[0066] In a preferred embodiment, the RPC cover plate can be provided with an accessory member;

[0067] The accessory member includes but is not limited to a supporting foot, an anti-skid pattern and a waist pinch, so as to facilitate the replacement of the ordinary concrete cover plate during the tunnel operation period.

[0068] It should be noted that the supporting foot can be adjusted in height, can better adapt to the replacement of the ordinary concrete cover plate during the tunnel operation period, solves the problem of inconsistent thickness of the new and old cover plates, specifically, the supporting foot can control the working height of the RPC cover plate by adjusting the height, is more suitable for the replacement of the ordinary concrete cover plate during the tunnel operation period, makes up for the defects of the thin thickness of the RPC cover plate and the inconsistent thickness of the original cover plate, and better adapts to the condition of replacing the cover plate in the operating tunnel.

[0069] It should be noted that the anti-skid pattern has an anti-skid effect and can be provided in at least one of a circular shape, a square shape, a cobblestone shape and a flower shape.

[0070] In addition, the waist pinch can be arranged at the middle line position of the cover plate body, when the maintenance path is maintained, the operator can move the cover plate body away without using any tool, and the edge of the cover plate is not damaged.

[0071] In a preferred embodiment, the interior of the RPC cover plate base body can be provided with a steel mesh;

[0072] The steel mesh includes but is not limited to a transverse steel bar and a longitudinal steel bar, so as to improve the folding resistance of the RPC cover plate.

[0073] The interior of the RPC cover plate base body is provided with the steel mesh, which can further improve the folding resistance of the cover plate; the transverse steel bar can be a smooth steel bar, including but not limited to at least one of a smooth steel bar with a diameter of φ5mm and a smooth steel bar with a diameter of φ6mm, and the length of the transverse steel bar can be 70mm-100mm, for example, 70mm, 80mm, 90mm or 100mm, but is not limited thereto; the longitudinal steel bar can be a smooth steel bar, including but not limited to at least one of a smooth steel bar with a diameter of φ5mm and a smooth steel bar with a diameter of φ6mm, and the length of the longitudinal steel bar can be 40mm-50mm, for example, 40mm, 42mm, 44mm, 46mm, 48mm or 50mm, but is not limited thereto.

[0074] According to a second aspect of the present application, a preparation method of the tunnel maintenance path RPC cover plate is provided, and the preparation method includes the following steps:

[0075] After mixing the components in proportion, pouring is carried out to obtain the RPC cover plate.

[0076] The preparation method further comprises the following steps:

[0077] After pouring, vibration is carried out, and a steel mesh is arranged in the paste during the vibration process, and steam curing is carried out to obtain the RPC cover plate.

[0078] A typical preparation method of a tunnel access RPC cover plate comprises the following steps:

[0079] (1) The cement, fly ash, silica fume, fine aggregate and fiber are mixed in proportion, and are put into the stirring chamber for dry mixing for not less than 5 minutes to ensure uniform dispersion of the fiber, to obtain dry mixture;

[0080] (2) The pigment and water reducing agent are mixed in water to obtain mixed slurry;

[0081] (3) The mixed slurry is poured into the stirring chamber, and stirring is carried out for not less than 4 minutes to obtain the concrete paste;

[0082] (4) A pouring pipe is arranged below the stirring chamber, and the pouring pipe can control the size of the discharge amount;

[0083] (5) A mold is arranged below the pouring pipe, the concrete paste is poured into the cover plate mold by opening the pouring pipe, and then is moved to a vibrating table in sequence for vibration, and a steel mesh is arranged in the paste during the vibration process;

[0084] (6) Plastic pads are installed at four corners of the steel mesh to control the thickness of the protective layer;

[0085] (7) The cover plate and the mold are integrally moved to a high-temperature steam curing chamber, high-temperature steam curing is carried out for not less than 48 hours, and the mold is removed;

[0086] (8) The cover plate is watered for not less than 7 days to obtain the RPC cover plate.

[0087] In the present application, the cement, fly ash, silica fume, fine aggregate and fiber are weighed and mixed in proportion, and are put into the stirring chamber for dry mixing for not less than 5 minutes to ensure uniform dispersion of the fiber, to obtain dry mixture; the weighing and stirring device is preferably an automatic stirring device, the automatic stirring device is provided with a stirring chamber, a feeding pipe is arranged at the top of the stirring chamber, and the other end of the feeding pipe is respectively connected with a cement tank, a fly ash tank, a silica fume tank, a fine aggregate tank, a fiber tank, an additive tank and a water tank; a weighing table is arranged below each of the cement tank, the fly ash tank, the silica fume tank, the fine aggregate tank, the fiber tank, the additive tank and the water tank; all materials are automatically weighed, and the weighed materials are put into the stirring chamber through the feeding pipe to ensure the accuracy of the material mixing ratio.

[0088] The pigment and additive are put into water to mix to obtain a mixed slurry, the mixed slurry is flowed into the stirring chamber through a feeding pipe, and the dry mixture is stirred for not less than 4 minutes.

[0089] A pouring pipe is arranged below the stirring chamber, a mold is arranged below the pouring pipe, the concrete slurry is poured into the cover plate mold by opening the pouring pipe, the internal dimension of the mold is 5cm in width, 80cm, 100cm or 120cm in length, and 2.5cm, 2.8cm or 3.0cm in thickness; the pouring pipe can control the size of the discharging amount to adapt to different mold sizes; the mold is sequentially moved to the vibrating table for vibrating for not less than 40s, and the reinforcement mesh is placed in the slurry during the vibrating process.

[0090] The reinforcement mesh comprises transverse reinforcement and longitudinal reinforcement, the transverse reinforcement is smooth reinforcement, the diameter type is φ5mm or φ6mm, and the length is 70mm-100mm; the longitudinal reinforcement is smooth reinforcement, the diameter type is φ5mm or φ6mm, and the length is 40mm-50mm, so that the folding resistance of the cover plate can be improved, and the plastic pad is arranged at four corners of the reinforcement mesh to control the thickness of the protective layer.

[0091] The mold is slidably connected with a mold feeding roller way, the cover plate and the mold are integrally moved to a high-temperature steam curing chamber, the mold is removed after high-temperature steam curing for not less than 48h, and the cover plate is watered for maintenance for not less than 7d to obtain the RPC cover plate.

[0092] According to a third aspect of the present application, the RPC cover plate of any one of the above is applied to municipal tunnel maintenance channel, highway tunnel maintenance channel, inspection well, sidewalk and subway evacuation passage.

[0093] The application of the tunnel maintenance channel RPC cover plate provided by the present application can achieve outstanding application effects.

[0094] The present application is further described below by examples. If not otherwise specified, the materials in the examples are prepared according to the existing method or directly purchased from the market.

[0095] Examples 1-5

[0096] Examples 1-5 provide a tunnel maintenance channel RPC cover plate, see Figure 1 , which is composed of an RPC cover plate base body 1, an accessory component and a reinforcement mesh;

[0097] The components of the RPC cover plate base body 1 of Examples 1-5 and the weight parts thereof are shown in Table 1 respectively;

[0098] The accessory component is composed of a supporting foot 2, an anti-skid pattern 3 and a waist pinch 4;

[0099] Specifically, the support foot 2 controls the working height of the RPC cover plate by adjusting the height, adapts to the replacement of the ordinary concrete cover plate in the tunnel operation period, and makes up for the defect that the thickness of the RPC cover plate is thin and inconsistent with the thickness of the original cover plate; the anti-skid pattern 3 has an anti-skid effect and is circular; the waist 4 is arranged at the middle line position of the cover plate body, and when the maintenance path is maintained, the operator does not need to use any tool and can only use the waist to move the cover plate body away, without damaging the edge of the cover plate.

[0100] The steel mesh is composed of transverse steel bars 5 and longitudinal steel bars 6. Figure 2

[0101] Specifically, the RPC cover plate base body 1 is internally provided with a steel mesh to improve the bending resistance of the RPC cover plate base body, which is composed of transverse steel bars 5 and longitudinal steel bars 6; the transverse steel bars 5 are smooth steel bars with a diameter of φ5mm and a length of 85mm; the longitudinal steel bars 6 are smooth steel bars with a diameter of φ5mm and a length of 45mm.

[0102] Table 1

[0103]

[0104] In Table 1, the particle size of the I-grade fly ash is not greater than 80μm; the semi-encrypted silica fume is easier to mix uniformly during the concrete mixing process, the particle morphology of the semi-encrypted silica fume can absorb free water, and the silica content in the semi-encrypted silica fume is not less than 92%; the fine aggregate is machine-made quartz sand, which is made of natural quartzite, and the fine aggregate includes coarse sand, medium sand and fine sand, the particle size of the coarse sand is 0.1mm-0.3mm, the particle size of the medium sand is 0.3mm-0.9mm, and the particle size of the fine sand is 0.9mm-5mm; the length of the short-end hook steel fiber is 17mm, and the diameter is 0.25mm; the length of the polypropylene fiber is 6.5mm, and the diameter is 30μm.

[0105] Example 6

[0106] The present embodiment is a preparation method of the RPC cover plate of Examples 1-5, which comprises the following steps:

[0107] (1) Mix the cement, fly ash, silica fume, fine aggregate and fiber according to the proportion, put them into the stirring chamber and dry mix for not less than 5 minutes to ensure uniform dispersion of the fiber, to obtain dry mixture;

[0108] (2) Mix the pigment and water reducing agent in water to obtain mixed slurry;

[0109] (3) Pour the mixed slurry into the stirring chamber and stir for not less than 4 minutes to obtain concrete slurry;

[0110] (4) A pouring pipe is arranged below the stirring chamber, which can control the size of the discharge amount; ​

[0111] (5) The mold is arranged below the pouring pipe, the concrete slurry is poured into the cover plate mold by opening the pouring pipe, and then moved to the vibrating table in sequence for vibration, and the reinforcement mesh is placed in the slurry during the vibration process;

[0112] (6) The plastic cushion block is installed at the four corners of the reinforcement mesh, and the thickness of the protective layer can be controlled;

[0113] (7) The cover plate and the mold are integrally moved to a high-temperature steam curing chamber, high-temperature steam curing is not less than 48h, and the mold is removed;

[0114] (8) The cover plate is watered for maintenance for not less than 7d, and the RPC cover plate is obtained.

[0115] Comparative Example 1

[0116] The difference between this comparative example and Example 1 is that the RPC cover plate base body does not contain short-end hook steel fibers, and the short-end hook steel fibers are replaced with an equal amount of cement;

[0117] The rest are the same as Example 1;

[0118] The preparation method refers to Example 6, and the RPC cover plate is obtained.

[0119] Comparative Example 2

[0120] The difference between this comparative example and Example 1 is that the weight fraction of the short-end hook steel fibers in the RPC cover plate base body is 44 parts;

[0121] The rest are the same as Example 1;

[0122] The preparation method refers to Example 6, and the RPC cover plate is obtained.

[0123] Comparative Example 3

[0124] The difference between this comparative example and Example 1 is that the weight fraction of the short-end hook steel fibers in the RPC cover plate base body is 134 parts;

[0125] The rest are the same as Example 1;

[0126] The preparation method refers to Example 6, and the RPC cover plate is obtained.

[0127] Comparative Example 4

[0128] The difference between this comparative example and Example 1 is that the RPC cover plate base body does not contain polypropylene fibers, and the polypropylene fibers are replaced with an equal amount of cement;

[0129] The rest are the same as Example 1;

[0130] The preparation method refers to Example 6, and the RPC cover plate is obtained.

[0131] Comparative Example 5

[0132] The difference between the present comparative example and Example 1 is that the weight fraction of polypropylene fibers in the RPC cover plate matrix is 5 parts;

[0133] The rest is the same as Example 1;

[0134] The preparation method refers to Example 6 to obtain the RPC cover plate.

[0135] Comparative Example 6

[0136] The difference between the present comparative example and Example 1 is that the weight fraction of polypropylene fibers in the RPC cover plate matrix is 16 parts;

[0137] The rest is the same as Example 1;

[0138] The preparation method refers to Example 6 to obtain the RPC cover plate.

[0139] Comparative Example 7

[0140] The difference between the present comparative example and Example 1 is that the RPC cover plate matrix does not contain fly ash, and the fly ash is replaced with an equal amount of cement;

[0141] The rest is the same as Example 1;

[0142] The preparation method refers to Example 6 to obtain the RPC cover plate.

[0143] Comparative Example 8

[0144] The difference between the present comparative example and Example 1 is that the RPC cover plate matrix does not contain silica fume, and the silica fume is replaced with an equal amount of cement;

[0145] The rest is the same as Example 1;

[0146] The preparation method refers to Example 6 to obtain the RPC cover plate.

[0147] Test Example

[0148] The RPC cover plates obtained in Examples 1-5 and Comparative Examples 1-8 are tested for performance, and the results are shown in Table 2.

[0149] The RPC concrete is cured according to the curing method of the test piece in GB / T50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete", and the curing age is 28d. The cured concrete is tested for the following performances:

[0150] Compressive strength: the compressive strength of the UHPC concrete sample is tested according to the test method of GB / T50081-2019 "Standard Test Methods of Physical and Mechanical Properties of Concrete", wherein the UHPC concrete sample is a cubic test piece, the edge length of the test piece is 150mm, and the loading speed is 1.0MPa / s during testing;

[0151] Flexural strength: the flexural strength of the UHPC concrete sample is tested according to the test method of GB / T50081-2019 "Standard Test Methods of Physical and Mechanical Properties of Concrete", wherein the UHPC concrete sample is a prismatic test piece, the edge length of the test piece is 150mm*150mm*600mm, and the loading speed is 0.08MPa / s during testing.

[0152] Table 2

[0153]

[0154] As shown in Table 2, the short hook steel fiber and polypropylene fiber are mixed to replace the steel fiber, which improves the flexural performance of the cover plate and reduces the cost of the cover plate; the RPC cover plates of examples 1-5 have high strength, high durability and thin thickness under the action of components and their ratios, which are obviously better than comparative examples 1-8.

[0155] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A tunnel access way RPC cover plate, characterized in that, The RPC cover plate matrix comprises the following components in parts by weight: 750-850 parts cement, 110-220 parts fly ash, 120-220 parts silica fume, 1000-1200 parts fine aggregate, 10-80 parts admixture, 130-160 parts water, and 80-120 parts fiber; The fibers include short-end hook steel fibers and polypropylene fibers; The short-end hook steel fiber accounts for 0.6% to 2% of the mass of the matrix, and the polypropylene fiber accounts for 0.1% to 0.2% of the mass of the matrix.

2. The tunnel maintenance access RPC cover plate according to claim 1, characterized in that, The RPC cover plate is equipped with auxiliary components; The auxiliary components include support feet, anti-slip patterns, and waist-shaped supports, which are used to facilitate the replacement of ordinary concrete cover plates during tunnel operation.

3. The tunnel maintenance access RPC cover plate according to claim 2, characterized in that, The support legs are height-adjustable support legs; Preferably, the anti-slip pattern includes at least one of circular, square, pebble-shaped, and flower-shaped patterns; Preferably, the waist is located at the middle edge of the cover plate body.

4. The tunnel maintenance access RPC cover plate according to claim 1, characterized in that, The RPC cover plate substrate is internally reinforced with a steel mesh. The steel mesh includes transverse and longitudinal steel bars to improve the flexural strength of the RPC cover plate.

5. The tunnel maintenance access RPC cover plate according to claim 4, characterized in that, The transverse reinforcing bars are smooth reinforcing bars; Preferably, the transverse reinforcing bars include at least one of plain steel bars with a diameter of φ5mm and plain steel bars with a diameter of φ6mm; Preferably, the length of the transverse reinforcing bar is 70mm to 100mm; Preferably, the longitudinal reinforcing bars are smooth reinforcing bars; Preferably, the longitudinal reinforcing bars include at least one of plain steel bars with a diameter of φ5mm and plain steel bars with a diameter of φ6mm; Preferably, the length of the longitudinal reinforcing bar is 40mm to 50mm.

6. The tunnel maintenance access RPC cover plate according to any one of claims 1-5, characterized in that, The cement includes 52.5 grade ordinary Portland cement; Preferably, the fly ash includes Class I fly ash; Preferably, the particle size of the fly ash is not greater than 80 μm; Preferably, the silica fume comprises semi-densified silica fume; Preferably, the silica content in the semi-densified silica ash is not less than 92%; Preferably, the fine aggregate comprises machine-made quartz sand.

7. The tunnel maintenance access RPC cover plate according to claim 6, characterized in that, The additives include at least one of water-reducing agents and pigments; Preferably, the water-reducing agent comprises a high-efficiency polycarboxylate liquid water-reducing agent; Preferably, the pigment includes at least one of inorganic pigments and organic pigments.

8. A method for preparing a tunnel maintenance access RPC cover plate according to any one of claims 1-7, characterized in that, Includes the following steps: The components are mixed in proportion and then poured to obtain the RPC cover plate.

9. The preparation method according to claim 8, characterized in that, The preparation method further includes the following steps: After pouring, the grout is vibrated, and during the vibration process, a steel mesh is placed in the grout. The grout is then steam-cured to obtain the RPC cover plate.

10. The application of the tunnel inspection road RPC cover plate according to any one of claims 1-7 in municipal tunnel inspection roads, highway tunnel inspection roads, manholes, sidewalks, and subway evacuation passages.

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