CN102976663A - Polymer modified polyethylene terephthalate (PET) concrete and preparation method thereof - Google Patents

Abstract

The invention discloses a polymer-modified PET concrete, which comprises a binder, aggregates and admixtures. According to the weight ratio, the binder+admixture:aggregate=1:1~3; the binder is PET, the admixture is fly ash, according to the weight ratio, PET: fly ash = 1:0.5~4, the aggregate is stone and sand, and the sand accounts for 20%~100% according to the weight percentage of the aggregate. The invention also discloses a preparation method of the concrete. The concrete can be prepared by using waste PET plastic bottles, which reduces environmental pollution. PET concrete has high compressive strength, flexural strength and early strength, and is suitable for various concrete structures with early strength, high impact resistance and high flexural strength.

Description

Polymer modified PET concrete and its preparation method

technical field

The invention relates to a concrete structure material technology, in particular to a polymer modified PET concrete and a preparation method thereof.

Background technique

At present, PET (the abbreviation of Polyethylene terephthalate in English, referred to as PET or PETP. Chinese means: polyterephthalic acid plastics, mainly including polyethylene terephthalate PET and polybutylene terephthalate PBT. Ethylene terephthalate (also commonly known as polyester resin, commonly known as polyester resin) is usually used in the production of daily consumer products such as plastic beverage bottles and food packaging bags. PET plastic beverage bottles have the advantages of light weight, easy production and convenient storage, and have replaced glass beverage bottles for the transportation and storage of carbonated beverages. A research report in 2007 showed that the weight of PET beverage bottles consumed in the world is about 10 million tons per year, and the annual growth rate is about 15% (ECO PET, 2007). Up to now, the annual consumption of about 20 million tons tons of PET raw materials. On the other hand, the amount of recycled PET is very limited. Usually, after using PET beverage bottles, people throw them away and turn them into waste PET, which brings a big problem that we have to build more facilities to store and process waste PET. Recycling is a very viable waste disposal method for thermoplastic materials. Sorting and recycling waste PET to produce new materials will effectively reduce the amount of waste PET, and the exponentially increasing amount of waste plastics every year has also promoted people to explore new ways to reuse plastic products. Recycling and reusing PET materials has made a significant contribution to the development of the plastics industry. It is reported that PET is the most abundant type of municipal solid waste, because PET materials cannot be biodegraded, so the quality of waste PET treatment has a major impact on the ecological environment. When recycling waste PET is not feasible, incineration of PET as an energy source has become the main treatment method. The air pollution and acid rain caused by waste combustion are a huge challenge to human survival. Greenpeace has been actively working to solve this problem question. The reduction and reuse of waste promotes economic development, and a large number of waste raw materials are recycled and used for other purposes, reducing waste and saving resources. The application of PET to concrete provides a new way for plastic processing, and at the same time reduces the environmental damage caused by collecting mineral raw materials (such as burning cement, etc.).

In concrete structures, such as road maintenance, the concrete pavement will be partially damaged due to factors such as load, environment, design, and construction. If these small-scale local diseases cannot be repaired effectively and timely, the scope of damage will be further expanded, the disease will be further aggravated, and eventually lead to more serious damage. When repairing, the strength growth rate of the material restricts the time for opening traffic. Early-strength, durable quick-repair materials can shorten road closure times and greatly reduce the impact on traffic. It has good social and economic significance to apply concrete with high early strength, high impact strength and high flexural strength to various concrete structures.

Niji Khoury of the University of Oklahoma and others mentioned the combination of PET and soil in "Soil Fused with Recycled Plastic Bottles for Various Geo-Engineering Application" Or the sand is heated and melted at 275°C to form a homogeneous plastic soil material, and the amount of PET used is PET: sand = 1:1. Nikki et al. did not conduct research on the use of hot-melt PET for the preparation of concrete, nor did they involve PET concrete for various concrete structures.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art, to provide a kind of polymer modified PET concrete and its preparation method, the concrete is prepared by PET, has higher compressive strength, flexural strength and early strength, suitable for It is suitable for various concrete structures with early strength, high impact resistance and high flexural strength.

To achieve the above object, the present invention adopts the following technical solutions:

A kind of polymer modified PET concrete, comprises binder, aggregate and admixture, by weight, binder+admixture:aggregate=1:1～3; Described binder is PET, adopts recycled The waste plastic bottles or newly produced PET materials are mixed with fly ash. According to the weight ratio, PET: fly ash=1:0.5~4, the aggregate is stone and sand, and the sand accounts for 20%~ according to the weight percentage of the aggregate. 100%.

The particle size of the stone is less than or equal to 31.5mm.

A preparation method of polymer modified PET concrete, the steps are as follows:

1) Prepare PET, fly ash and aggregate according to weight ratio;

2) Mix and stir fly ash and PET for 2min~5min;

3) Then add the aggregate and continue to stir for 3min~5min;

4) Heat at 270-290°C for 2h-3h to make the mixture into a fluid state and then use it. Stir again for 1min before use.

The PET used in the present invention is used as a binder in the concrete, the sand and gravel used are used as aggregates of the concrete, and the fly ash is used as an admixture to partially replace the PET and increase the workability of the concrete. By optimizing the amount of PET and the gradation of aggregates, the compressive strength, flexural strength and early strength of PET concrete are effectively improved, and this PET concrete is applied to various early strength, high impact resistance and high flexural strength in the concrete structure.

The present invention develops three kinds of PET concretes according to the aforementioned technical scheme.

The first is to use PET as a binder, basalt and sand with a maximum particle size of 13.2mm as aggregates, and the admixture is fly ash. According to PET: fly ash = 1:1, mix to make the first PET concrete;

The second is to use PET as the binder, limestone and sand with a maximum particle size of 9.5mm as the coarse aggregate, and the admixture is fly ash. According to PET: fly ash = 1:0.5, mix to make the second type PET concrete;

The third is to use PET as the binder, limestone and sand with a maximum particle size of 9.5mm as the coarse aggregate, and the admixture is fly ash. According to PET: fly ash = 1:1, mix to make the third type PET concrete.

The test shows that under the condition of PET+fly ash:aggregate=1:3, the compressive strength of the first PET concrete is 34.04MPa, and the flexural strength is 12.23MPa, of which the flexural strength is higher than the special-grade pavement requirement 2 times; the compressive strength of the second type of PET concrete is 27.8MPa, and the flexural strength is 9.56MPa, of which the flexural strength is 1.59 times higher than that required for super-grade pavement; the compressive strength of the third type of PET concrete is 36MPa, and the flexural strength It is 9.09MPa, and the flexural strength is 1.5 times higher than the highway pavement requirements.

The beneficial effects of the present invention are:

1. A new method of recycling waste PET is proposed, which can effectively reduce the damage of waste PET to the ecological environment.

2. The raw materials used in PET concrete are easy to obtain and the price is low, and the manufacturing process is simple.

3. The designed PET concrete mix ratio, because it can reach strength in about 3 hours, can be effectively used in various concrete structures such as roads, bridges, and buildings.

4. PET concrete has good flexural properties and can be used in concrete structures that require early strength, high flexural strength and high impact strength.

Description of drawings

Fig. 1 is the picture of PET concrete compression test piece;

Figure 2 is a picture of the PET concrete flexural test piece;

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Example:

Material formula

The PET used is a waste plastic bottle. Before use, remove the label and cap to obtain a relatively pure PET material. After cutting the bottle into small PET fragments, wash it properly with clean water and dry it before use.

The coarse aggregate used is limestone with a maximum particle size of 9.5mm or basalt crushed stone with a maximum particle size of 13.2mm. The crushed stone is washed and dried before use.

The fine aggregate used is ordinary river sand and medium sand with a maximum particle size of 4.75 mm.

The admixture used is fly ash.

The gradation range of the aggregates used is designed according to the Fuller gradation, respectively according to the maximum particle size of 13.2mm and the maximum particle size of 9.5mm. See Table 1 and Table 2 for details.

Table 1 Requirements for the gradation range with a maximum particle size of 13.2 mm

Table 2 Requirements for the gradation range with a maximum particle size of 9.5 mm

For every 100g of aggregate, the quality of aggregates of various particle sizes is shown in Table 3 and Table 4.

Table 3 The mass used for each particle size aggregate when the maximum particle size is 13.2mm

Table 4 The mass used for each particle size aggregate when the maximum particle size is 9.5mm

Based on PET, the amount of fly ash is: PET: fly ash = 1:0.5~4 (mass ratio)

Based on the mixture of PET and fly ash, the amount of aggregate is: PET + fly ash: aggregate = 1:1~3 (mass ratio)

2. Preparation method

PET concrete 1 is produced by using PET and basalt with a coarse aggregate of a maximum particle size of 13.2 mm. The preparation process is as follows: weighing according to the amount of aggregates of each particle size specified in Table 3, and the amount of PET is determined as PET: pulverized coal Ash=1:1, PET+fly ash: aggregate=1:3. Mix and stir fly ash and PET for 2 minutes, then add aggregate and continue stirring for 3 minutes, heat at 270-290°C for 2 hours to 3 hours, make the mixture flowable and then use it, and stir again for 1 minute before use.

Use PET and limestone with a coarse aggregate particle size of 9.5 mm to make PET concrete 2. The preparation process is as follows: weigh the amount of aggregates of each particle size specified in Table 4, and the amount of PET is determined as PET: fly ash =1:0.5, PET+fly ash: aggregate =1:3. Mix fly ash and PET and stir for 5 minutes, then add aggregate and continue stirring for 5 minutes, heat at 270-290°C for 2 hours to 3 hours, make the mixture flowable and then use it, and stir again for 2 minutes before use.

PET concrete 3 made by using PET and limestone with a maximum particle size of 9.5 mm of coarse aggregate, the preparation process is: weighing according to the amount of aggregates of each particle size specified in Table 4, and the amount of PET is determined as PET: pulverized coal Ash=1:1, PET+fly ash: aggregate=1:3. Mix fly ash and PET for 3 minutes, then add aggregate and continue stirring for 4 minutes, heat at 270-290°C for about 2 hours to 3 hours, make the mixture flowable and then use it, and stir again for 1.5 minutes before use.

According to the different particle sizes of aggregates and the proportion of PET:fly ash, four kinds of PET concrete with mix ratio were produced. The time for PET concrete to solidify and reach the final strength is 3 hours, and it has strong early strength.

PET concrete 1 uses basalt with a coarse aggregate particle size of 13.2 mm, PET: fly ash = 1:1, PET+ fly ash: aggregate = 1:3, the basic properties of PET concrete 1 are shown in Table 5

Table 5 Basic properties of PET concrete 1

nature unit value Gross volume density kg/ ^m3 2000 water absorption % <1% Compressive strength MPa 34.04 Flexural strength MPa 12.23

It can be seen from Table 5 that PET concrete 1 has a lower water absorption rate, better anti-permeability, compressive strength meets the requirements of the road surface, and the flexural strength meets the requirements of the special road surface twice.

PET concrete 2 uses limestone with a coarse aggregate particle size of 9.5mm, PET: fly ash = 1:0.5, PET+ fly ash: aggregate = 1:3, the basic properties of PET concrete 2 are shown in Table 6

Table 6 Basic properties of PET concrete 2

nature unit value Gross volume density kg/ ^m3 1900 water absorption % <1% Compressive strength MPa 27.80 Flexural strength MPa 9.56

It can be seen from Table 6 that the compressive strength of PET concrete 2 meets the pavement requirements, and the flexural strength meets 1.59 times of the super-grade pavement requirements.

PET concrete 3 uses limestone with a coarse aggregate particle size of 9.5 mm, PET: fly ash = 1:1, PET+ fly ash: aggregate = 1:3, the basic properties of PET concrete 3 are shown in Table 7

Table 7 Basic properties of PET concrete 3

nature unit value Gross volume density kg/ ^m3 1950 water absorption % <1% Compressive strength MPa 36.00 Flexural strength MPa 9.09

It can be seen from Table 7 that the compressive strength of PET concrete 3 meets the requirements of the pavement, and is the highest among the three mix ratios, and the flexural strength meets 1.5 times the requirements of the super-grade pavement.

From the properties of PET concrete in Table 5, Table 6 and Table 7, the compressive strength can be guaranteed at 25MPa~36MPa, and the flexural strength is about 9MPa~12MPa, which has good compressive and flexural strength and can be applied to various A concrete structure. Observing the PET concrete specimens (Figure 1, Figure 2), it was found that the surface of the PET concrete was smooth and flat without cracks.

Although the specific implementation of the present invention has been described above in conjunction with the accompanying drawings, it does not limit the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, those skilled in the art do not need to pay creative work Various modifications or variations that can be made are still within the protection scope of the present invention.

Claims (6)

1. A polymer modified PET concrete is characterized in that, comprises binding agent, aggregate and admixture, by weight, binding agent+admixture: aggregate=1:1～3. 2. polymer modified PET concrete as claimed in claim 1 is characterized in that, described binding agent is PET, adopts the waste plastic bottle of recovery or new production PET material. 3. polymer modified PET concrete as claimed in claim 2, is characterized in that, described admixture is fly ash, by weight ratio, PET: fly ash=1:0.5～4, 4. The polymer-modified PET concrete according to claim 1, wherein the aggregates are stones and sand, and the sand accounts for 35% to 100% by weight of the aggregate. 5. The polymer modified PET concrete as claimed in claim 4, characterized in that, the particle diameter of the stone is less than or equal to 31.5mm. 6. a kind of preparation method of polymer modified PET concrete as described in claim 1, its steps are as follows: 1) Prepare PET, fly ash and aggregate according to weight ratio; 2) Mix and stir fly ash and PET for 2min~5min; 3) Then add the aggregate and continue stirring for 3min~5min; 4) Heat at 270-290°C for 2h-3h to make the mixture into a fluid state and then use it. Stir again for 1min-2min before use.