CN112028574B - Concrete material suitable for manufacturing bridge prestressed pipe pile - Google Patents

Abstract

The invention relates to a concrete material suitable for manufacturing a bridge prestressed pipe pile, which comprises the following components in parts by weight: 100-120 parts of ordinary portland cement, 80-100 parts of fly ash portland cement, 40-60 parts of slag powder, 400-600 parts of broken stone, 200-400 parts of sand, 40-70 parts of water and 1-5 parts of composite modified water reducing agent. The prestressed bridge pipe pile produced by the concrete material has the advantages of no pollution to the environment, good grouting compactness, good bending resistance and bearing performance, good seismic resistance, low temperature influence degree and good water resistance, acid and salt erosion resistance.

Description

Concrete material suitable for manufacturing bridge prestressed pipe pile

Technical Field

The invention belongs to the technical field of building materials, and relates to a concrete material suitable for manufacturing a bridge prestressed pipe pile.

Background

The prestressed high-strength concrete pipe pile is the most commonly used concrete member in building foundation, and is widely applied to various buildings, traffic, water conservancy and other projects. For example, when the grouting material is applied to bridge construction, the compactness of grouting has an important influence on the service life of the bridge. According to statistics, the actual service life of the bridge can be shortened to one tenth of the design service life due to the fact that the steel strand in the prestressed pipeline is corroded and the prestress is lost in advance due to the fact that grouting is not compact.

In addition, during the actual service period, the bridge prestressed pipe pile is also affected by various environmental factors, such as physical, chemical or biological erosion effects of atmosphere, water and the like, and contraction and expansion effects caused by temperature and humidity changes, and is also subjected to various dynamic loads and static loads, so that concrete in the bridge prestressed pipe pile is cracked, falls off, leaks and is corroded, the stress bearing capacity and the impermeability of the bridge prestressed pipe pile are greatly affected, and a great safety hazard is caused.

Based on the above problems, there is a need to develop a concrete material for preparing a prestressed bridge pipe pile, which has good grouting compactness, good bending resistance and bearing performance, good anti-seismic performance, low temperature influence degree, good water resistance, acid and salt corrosivity, and long service life.

Disclosure of Invention

An object of the present invention is to overcome the above-mentioned drawbacks of the prior art and to provide a concrete material suitable for manufacturing a prestressed pipe pile for a bridge.

The invention also aims to provide a method for preparing the bridge prestressed pipe pile by adopting the concrete material.

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

in one aspect of the invention, the concrete material suitable for manufacturing the bridge prestressed pipe pile comprises the following components in parts by weight: 100-120 parts of ordinary portland cement, 80-100 parts of fly ash portland cement, 40-60 parts of slag powder, 400-600 parts of broken stone, 200-400 parts of sand, 40-70 parts of water and 1-5 parts of a composite modified water reducing agent.

In one embodiment, the portland cement is selected from a class 52.5 portland cement or a class 52.5R portland cement, and the fly ash portland cement is selected from a class 42.5R fly ash portland cement.

In one embodiment, the slag powder is selected from powders having a specific Boehringer surface area of greater than 450 m ² Per kg of water-quenched blast furnace slag powder.

In one embodiment, the crushed stone has a particle size of not more than 20mm, and the sand has a particle size of not more than 0.5mm.

As an embodiment, the composite modified water reducing agent is prepared by mixing the following components in percentage by weight: 10-20% of polycarboxylic acid water reducing agent, 60-75% of graphene modified lignosulfonate water reducing agent and the balance of methanol polyoxyethylene ether.

As an embodiment, the graphene modified lignosulfonate water reducing agent is prepared by chemically bonding functionalized graphene and lignosulfonate.

In one embodiment, the functionalized graphene is obtained by modifying the surface of graphene with a silane coupling agent.

As an embodiment, the preparation method of the graphene modified lignosulfonate water reducing agent comprises the following steps: mixing lignosulfonate, functionalized graphene and an antioxidant in a solvent, adding a catalyst, reacting at 75-90 ℃ for 2-5 hours, and cooling to room temperature.

In a preferred embodiment, the antioxidant is n-octadecyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate; the catalyst is selected from one or more of ferrous sulfate, sodium sulfite, sodium bisulfite and sodium metabisulfite.

As a preferred embodiment, the amount of the functionalized graphene is 0.5-2 wt% of the inventory amount of the lignosulfonate; the using amount of the antioxidant is 2-4 wt% of the inventory rating of the lignosulfonate; the dosage of the catalyst is 0.1-0.5 wt% of the dosage of the lignosulfonate.

As a preferred embodiment, the solvent is water; the functionalized graphene is firstly dispersed in absolute ethyl alcohol, and then is added into a solvent to be mixed with lignosulfonate and an antioxidant, wherein the mass fraction of the functionalized graphene in the absolute ethyl alcohol is 5-30%.

In another aspect of the invention, the bridge prestressed pipe pile is made of the concrete material.

The preparation method of the bridge prestressed pipe pile is characterized by comprising the following steps of:

step 1): pouring ordinary portland cement, fly ash portland cement, slag powder, broken stone and sand into a stirrer according to the parts by weight, stirring and mixing uniformly, adding water and a composite modified water reducing agent into the stirrer according to the parts by weight, and continuously stirring until the mixture is uniformly mixed to obtain a concrete mixture for later use;

step 2): adding the concrete mixture into a mould, carrying out normal pressure curing after forming, firstly preserving heat for 1-2 hours at 25-30 ℃, then placing the mixture into a steam curing pool, raising the temperature to 50-60 ℃ at a constant speed within 2 hours, then preserving heat for 2-4 hours at 50-60 ℃, cooling, demoulding, and carrying out open-air curing for 2 days.

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

1) The composite modified water reducing agent adopted in the concrete material comprises a graphene modified lignosulfonate water reducing agent, and is characterized in that the chemical reaction of functionalized graphene and lignosulfonate is catalyzed by utilizing the characteristic of an active functional group on the surface of the functionalized graphene under the protection of an antioxidant, so that the functionalized graphene is efficiently grafted to the lignosulfonate, the functional graphene can be effectively prevented from agglomerating, the functionalized graphene is favorable for the dispersibility of the functionalized graphene in a composite modified water reducing agent system, meanwhile, a polycarboxylic acid water reducing agent is introduced into the composite modified water reducing agent, the polycarboxylic acid water reducing agent and the graphene modified lignosulfonate water reducing agent can play a synergistic effect, the water reducing rate is high, the compatibility between the composite modified water reducing agent and cement and admixture can be remarkably improved, the temperature adaptability of a final material is further favorable for improving, the shrinkage of concrete can be remarkably reduced, and the slump loss is small;

2) In the composite modified water reducing agent adopted by the invention, due to the introduction of the functionalized graphene, the high temperature resistance and the cold resistance of the final material can be effectively improved, the sensitivity of the final material to temperature can be reduced, the degree of self shrinkage or expansion of the material system due to temperature change can be reduced, and the service life of the material system can be prolonged;

3) The prestressed bridge pipe pile produced by the concrete material has the advantages of no pollution to the environment, good grouting compactness, good bending resistance and bearing performance, good seismic resistance, low temperature influence degree and good water resistance, acid and salt erosion resistance.

Detailed Description

The inventor finds that by introducing a composite modified water reducing agent comprising a graphene modified lignosulfonate water reducing agent and a polycarboxylic acid water reducing agent into a material system of cement, mineral admixture and sand, the temperature adaptability of a final material can be effectively improved, the sensitivity of the final material to temperature can be reduced, the degree of self contraction or expansion of the material system due to temperature change can be reduced, the contraction of concrete is remarkably reduced, the slump loss is small, and the bending resistance, the bearing capacity and the shock resistance of the material system can be improved.

On the basis of this, the present invention has been completed.

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 components and their parts by weight contents of concrete materials of examples 1 to 5 and comparative examples.

TABLE 1 examples 1-5 and comparative concrete material formulations

Note: in Table 1, the slag powder has a Boehringer specific surface area of more than 450 m ² Per kg of water-quenched blast furnace slag powder; the particle size of the crushed stone is not more than 20mm; the grain size of the sand is not more than 0.5mm.

The preparation method of the graphene modified lignosulfonate water reducing agent adopted in the embodiments 1 to 5 is as follows:

mixing lignosulfonate, functionalized graphene and an antioxidant in a solvent, adding a catalyst, reacting at 75-90 ℃ for 2-5 hours, and cooling to room temperature.

In the actual preparation process, the functionalized graphene can be firstly dispersed in absolute ethyl alcohol, and then added into a solvent to be mixed with lignosulfonate and an antioxidant, wherein the mass fraction of the functionalized graphene in the absolute ethyl alcohol is 5-30%.

The following table 2 shows specific preparation process conditions of the graphene modified lignosulfonate water reducing agents adopted in examples 1-5.

Table 2 examples 1-5 preparation process conditions of graphene modified lignosulfonate water-reducing agent

Note: the amounts of the functionalized graphene, the catalyst and the antioxidant in table 2 are all percentages of the lignosulfonate feed amount.

It should be noted that the antioxidant used in the preparation of the graphene modified lignosulfonate water reducing agent in the above examples 1-5 is β - (3, 5-di-tert-butyl-4-hydroxyphenyl) n-octadecyl propionate, and the solvent used is water.

The preparation method of the functionalized graphene used in the above examples 1 to 5 is as follows:

the method comprises the following steps: the Hummers method can be used to prepare graphene oxide, for example, the following steps can be used:

2 g of graphite and 1 g of NaNO ₃ 46 ml of 98% concentrated sulfuric acid, the mixture was placed in an ice-water bath, stirred for 30 minutes to mix the mixture sufficiently, and 6 g of KMnO was weighed ₄ Adding into the above mixed solution for several times, stirring for 2 hr, transferring into 35 deg.C warm water bath, and stirring for 30 min; slowly adding 92 ml of distilled water, controlling the temperature of the reaction liquid to be about 98 ℃ for 15 minutes, and adding a proper amount of 30% H ₂ O ₂ Removing excessive oxidant, adding 140 mL of distilled water for dilution, filtering while hot, and washing with 0.01 mol/L HCl, absolute ethyl alcohol and deionized water in sequence until no SO is in the filtrate ₄ ^2- Until the graphite exists, preparing graphite oxide; then will beUltrasonically dispersing graphite oxide in water to prepare a dispersion liquid of graphene oxide; and (3) drying the dispersion liquid of the graphene oxide in a vacuum drying oven at 60 ℃ for 48 hours to obtain a graphene oxide sample, and storing for later use.

Step two: taking silane coupling agent KH-570 as an example, the following steps can be used to prepare functionalized graphene oxide:

weighing 100 mg of graphene oxide in 60 mL of absolute ethyl alcohol, and performing ultrasonic dispersion for 1 hour to form a uniform dispersion liquid; adding a certain amount of HCl, and adjusting the pH value of the dispersion liquid to 3-4; then, slowly adding 10 mL of 95% ethanol solution containing 0.3 g of KH-570 under stirring, continuously reacting for 24 hours at 60 ℃, centrifugally separating, washing with absolute ethanol and deionized water for multiple times to remove unreacted KH-570, and making the washing liquid to be neutral to obtain the functionalized graphene oxide.

Step three: the functionalized graphene oxide can be reduced to functionalized graphene with a suitable reducing agent (e.g., hydrazine hydrate), for example, the following steps can be employed:

dispersing washed and undried functionalized graphene oxide in 60 mL of absolute ethyl alcohol, performing ultrasonic dispersion for 1 hour to form uniform and stable functionalized graphene oxide dispersion liquid, then adding 1 g of hydrazine hydrate, and reducing for 24 hours at 60 ℃; and washing the obtained product with absolute ethyl alcohol and deionized water to neutrality, and drying the product in a vacuum drying oven at 60 ℃ for 48 hours to obtain the functionalized graphene, and storing for later use.

It should be understood that the preparation method of the functionalized graphene according to the present invention is not limited to the description in the above example, and other suitable methods may be adopted to modify the surface of the graphene.

The concrete materials of examples 1 to 5 and comparative example were made into a prestressed bridge pipe pile by the following method:

step 1): pouring ordinary portland cement, fly ash portland cement, slag powder, broken stone and sand into a stirrer according to the parts by weight, stirring and mixing uniformly, adding water and a composite modified water reducing agent into the stirrer according to the parts by weight, and continuously stirring until the mixture is uniformly mixed to obtain a concrete mixture for later use;

step 2): adding the concrete mixture into a mould, after forming, carrying out normal pressure curing, firstly preserving heat for 2 hours at 25 ℃, then placing the mixture into a steam curing pool, raising the temperature to 60 ℃ at a constant speed within 2 hours, then preserving heat for 2 hours at 60 ℃, cooling, demoulding, and carrying out open-air curing for 2 days.

The method for preparing the bridge prestressed pipe pile by using the concrete material of the embodiment 4-5 is basically the same as the embodiment 1-3, except that: adding the concrete mixture into a mould in the step 2), carrying out normal pressure curing after forming, firstly preserving heat for 1 hour at 30 ℃, then placing the mixture into a steam curing pool, raising the temperature to 50 ℃ at a constant speed within 2 hours, then preserving heat for 4 hours at 50 ℃, cooling, demoulding, and carrying out open-air curing for 2 days.

Table 3 below shows the performance test results of the prestressed bridge pipe piles made of the materials of examples 1 to 5 and comparative example.

Table 3 results of performance test of prestressed pipe piles for bridges made of examples 1 to 5 and comparative example materials

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 (3)

1. The concrete material is suitable for manufacturing the bridge prestressed pipe pile and is characterized in that,

comprises the following components in parts by weight: 100-120 parts of ordinary portland cement, 80-100 parts of fly ash portland cement, 40-60 parts of slag powder, 400-600 parts of broken stone, 200-400 parts of sand, 40-70 parts of water and 1-5 parts of a composite modified water reducing agent;

the composite modified water reducing agent is prepared by mixing the following components in percentage by weight: 10-20% of a polycarboxylic acid water reducing agent, 60-75% of a graphene modified lignosulfonate water reducing agent and the balance of methanol polyoxyethylene ether;

the preparation method of the graphene modified lignosulfonate water reducing agent comprises the following steps: mixing lignosulfonate, functionalized graphene and an antioxidant in a solvent, adding a catalyst, reacting at 75-90 ℃ for 2-5 hours, and cooling to room temperature;

the dosage of the functionalized graphene is 0.5-2 wt% of the inventory rating of lignosulfonate;

the using amount of the antioxidant is 2-4 wt% of the inventory rating of the lignosulfonate;

the dosage of the catalyst is 0.1 to 0.5 weight percent of the inventory rating of the lignosulfonate;

the ordinary portland cement is selected from 52.5-grade ordinary portland cement or 52.5R-grade ordinary portland cement, and the fly ash portland cement is selected from 42.5R-grade fly ash portland cement;

the slag powder is selected from Boehringer's specific surface area larger than 450 m ² Per kg of water-quenched blast furnace slag powder;

the particle size of the broken stone is not more than 20mm, and the particle size of the sand is not more than 0.5mm;

the antioxidant is beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) n-octadecyl propionate;

the catalyst is selected from one or more of ferrous sulfate, sodium sulfite, sodium bisulfite and sodium metabisulfite.

2. A prestressed pipe pile for bridge, which is made of the concrete material according to claim 1.

3. The method for preparing a prestressed pipe pile for a bridge according to claim 2,

the method comprises the following steps:

step 1): pouring ordinary portland cement, fly ash portland cement, slag powder, broken stone and sand into a stirrer according to the parts by weight, stirring and mixing uniformly, adding water and a composite modified water reducing agent into the stirrer according to the parts by weight, and continuously stirring until the mixture is uniformly mixed to obtain a concrete mixture for later use;

step 2): adding the concrete mixture into a mould, carrying out normal pressure curing after forming, firstly preserving heat for 1-2 hours at 25-30 ℃, then placing the mixture into a steam curing pool, raising the temperature to 50-60 ℃ at a constant speed within 2 hours, then preserving heat for 2-4 hours at 50-60 ℃, cooling, demoulding, and carrying out open-air curing for 2 days.