CN114804756B - Continuous-grain-size graded rubber powder concrete and preparation method thereof - Google Patents

Abstract

The invention discloses a continuous particle size gradation rubber powder concrete and a preparation method thereof. The continuous particle size gradation rubber concrete refers to that the rubber powder in the continuous particle size range is used to replace the corresponding particle size in the fine aggregate gradation. range, maintaining the existing gradation of fine aggregate unchanged. The raw materials include: ordinary Portland cement, river sand, rubber aggregate, NaOH solution, crushed stone, and water. The invention aims to solve the problem that the gradation integrity of the fine aggregate containing rubber powder cannot be maintained before and after the rubber aggregate is replaced. The working performance of the graded rubber concrete prepared by the method has been significantly improved, the mechanical properties have been significantly improved, the toughness is strong, and the durability is better. By maintaining the continuous and complete gradation of the fine aggregate containing rubber powder, the method obtains the gradation rubber powder mix ratio and the preparation method that meet the requirements of engineering practice. It will provide new kinetic energy to solve the difficulties in the disposal of waste tires and the shortage of natural aggregates.

Description

A kind of graded rubber powder concrete with continuous particle size and its preparation method

technical field

The invention relates to the field of new building materials, in particular to a graded rubber powder concrete with continuous particle size and a preparation method thereof.

Background technique

At present, with the continuous development of the global transportation industry, the number of waste tires produced every year is in units of 100 million, and it keeps increasing year by year. It is conceivable that hundreds of millions of waste tires will put pressure on the environment. The process of stacking waste tires is also easy to cause fires and breed bacteria. Therefore, how to deal with it scientifically and effectively has become a hot spot for scholars from all over the world. At the same time, with the rapid advancement of my country's urbanization process, the demand for natural aggregates will also rise sharply. If the waste tires are ground into rubber powder with a specific particle size to replace the natural fine aggregates in the concrete, a scientific treatment method for waste tires can be found, and at the same time, the troubles caused by the shortage of natural aggregates can be alleviated. .

Due to its high toughness and strong impact resistance, rubber concrete is attracting the attention of many researchers, and a series of experimental studies have been carried out. However, due to the replacement of fine aggregate by rubber, the problems of low compressive strength, large shrinkage, and poor durability of concrete are put on hold, and they are used in some non-load-bearing structures. The reason is mainly because the bonding between rubber and cement slurry is poor after adding, and the elastic modulus of rubber itself is low.

In the current research, rubber is mainly used to replace fine aggregate. In existing studies, fixed particle size or partially continuously graded rubber powder is used to quantitatively replace fully graded natural fine aggregate, and such a replacement method will lead to discontinuous gradation of the replaced part of the aggregate, resulting in uneven distribution of pore sizes inside the concrete , deterioration of mechanical properties.

Contents of the invention

Aiming at the problem that the gradation continuity and integrity of fine aggregate containing rubber powder cannot be maintained after rubber powder replaces natural fine aggregate in existing research, this paper proposes a graded rubber concrete with fixed particle size and its preparation method.

The object of the present invention adopts following technical scheme to realize:

In the first aspect, the present invention provides a graded rubber powder concrete with continuous particle size, calculated in parts by weight, including the following raw materials:

420 parts of cement, 553.5-615 parts of fine aggregate, 24.78 parts of rubber powder, 1194 parts of coarse aggregate and 210 parts of water.

Preferably, the cement is P.O42.5 ordinary Portland cement.

Preferably, the fine aggregate is graded as zone 2 medium sand, and the fineness modulus is 2.69.

Preferably, the cumulative sieve percentages of fine aggregate are 4.75: 2.36: 1.18: 0.60: 0.30: 0.15 = 0%: 10.1%: 29.2%: 50.2%: 79.4%: 100%.

Preferably, the rubber powder is waste rubber powder, and the particle size range is between 0-0.3mm, 0.3-0.6mm, 0.6-1.18mm, 1.18-2.36mm and 2.36-4.75mm.

Preferably, the coarse aggregate is crushed stone with a maximum particle size of 20mm, wherein about 37% of the crushed stone is 5-10mm, and about 63% is about 63% of the crushed stone of 10-20mm.

Second aspect, the present invention provides a kind of preparation method of the graded rubber concrete of continuous particle size, comprises the steps:

(1) first put rubber powder into NaOH solution and soak, then use tap water to clean, until the pH value reaches 7, the rubber powder is ventilated and dried for subsequent use;

(2) Three fine aggregate samples of equal quality were randomly selected for sieving test, and the remaining percentage of each sieve hole was counted, and then the results obtained from the three tests were averaged to obtain the gradation curve of the fine aggregate in this test. The accumulative sieving percentages of fine aggregate are 4.75: 2.36: 1.18: 0.60: 0.30: 0.15 = 0%: 10.1%: 29.2%: 50.2%: 79.4%: 100%.

(3) Weigh the required fine aggregate according to the amount and carry out screening, and divide according to 5 sections of 0-0.30mm, 0.30-0.60mm, 0.60-1.18mm, 1.18-2.36mm and 2.36-4.75mm for standby;

(4) Take the rubber powder in the required two adjacent particle size intervals according to the amount, and quantitatively replace the corresponding adjacent particle size sections in the 5 sections in step (3), then follow the steps in step (2) The grading curve mixes the remaining fine aggregates according to the grading to obtain the grading fine aggregates containing rubber aggregates;

(5) Take the cement according to the amount, mix it with the graded fine aggregate containing the rubber aggregate, add the forced mixer to stir evenly, then add the coarse aggregate weighed according to the amount, water successively, and stir evenly;

(6) Put the concrete obtained in step (5) into a mold, place it on a vibrating table, vibrate evenly, and perform standard maintenance to obtain rubber concrete.

Preferably, the NaOH solution has a concentration of 1 mol/L, and is prepared by using sodium hydroxide flake solid with a solid content of 96%.

Preferably, the soaking time in the NaOH solution is 1 hour, and the stirring is performed once every 10 minutes.

Preferably, the three fine aggregate samples are each 500 g in the sieve test.

The beneficial effects of the present invention are:

1) Aiming at the problems of low compressive strength, poor durability and large shrinkage in existing rubber concrete, a graded rubber concrete with continuous particle size and its preparation method are proposed. This method starts from the problem that the gradation continuity of the replacement part cannot be guaranteed in the process of replacing fine aggregate with rubber aggregate, and proposes to use rubber aggregate with continuous particle size to quantitatively replace the corresponding segment range in the particle gradation of fine aggregate. Thereby ensuring the continuity of fine aggregate gradation before and after replacement. The method is beneficial to reduce the degree of degradation of mechanical properties caused by the replacement of fine aggregate by rubber particles, improve the uniform distribution of internal pore sizes of rubber concrete, reduce the shrinkage of rubber concrete, and greatly improve the mechanical and durability properties of rubber concrete.

2) In the present invention, the ductility and impact resistance of the concrete are significantly improved by replacing the natural fine aggregate with rubber particles. lead to a decrease in the mechanical properties of concrete.

3) The rubber particles involved in the present invention come from the reprocessing and reuse of waste tires. Rubber particles replace natural fine aggregate in concrete, which will help reduce the consumption of natural aggregate. Therefore, the present invention actively responds to the policy of "carbon peaking and carbon neutrality" proposed by our country, and will also provide a reference for the treatment of waste tires and the solution to the shortage of natural aggregates.

Detailed ways

In order to illustrate the present invention more clearly and have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solutions of the present invention are now described in detail below, but it cannot be interpreted as limiting the scope of the present invention.

Aiming at the inability to guarantee the continuous gradation of the substituting part in the process of substituting rubber aggregates for fine aggregates in the existing research, the present invention proposes for the first time a replacement method for rubber particles with continuous particle diameters to specifically replace the corresponding particle size range in the gradation of natural fine aggregates. This replacement method will ensure the continuous gradation of rubber concrete to the greatest extent, and obtain rubber concrete with better mechanical and durability properties.

The present invention expects to optimize the internal pore size distribution of concrete and improve its mechanical and dynamic properties by adjusting the replacement mode of rubber powder. A substitution method in which the continuous rubber powder particle size replaces the corresponding section range in the fine aggregate gradation and keeps the rest of the section unchanged is proposed. The invention aims at solving the degradation of the mechanical properties of the rubber powder concrete, providing a corresponding solution, and promoting the further application of the rubber powder concrete in practical engineering. At the same time, it is also expected to provide corresponding reference and basis for the subsequent development of rubber powder concrete.

For the first time, this invention starts from the particle gradation of rubber replacing part, and proposes the concept that the continuity of gradation should be ensured before and after the replacement of fine aggregate by rubber particles. The rubber graded concrete has been significantly improved in terms of mechanical properties, durability, shrinkage, etc., and will provide a reference for the actual engineering application of rubber concrete. At the same time, the invention patent actively responds to the national goal of "carbon peaking and carbon neutrality", and provides new development momentum for the reprocessing and reuse of waste tires and the shortage of natural aggregates.

The present invention is further described in conjunction with the following examples.

Example 1

A graded rubber concrete with continuous particle size and a preparation method thereof, calculated in parts by weight, comprising the following raw materials:

420 parts of cement, 553.5 parts of fine aggregate, 24.78 parts of rubber powder, 1194 parts of coarse aggregate, and 210 parts of water. The particle size of the rubber powder is 0-0.3mm, 0.3-0.6mm, replacing the 0-0.3mm, 0.3-0.6mm sections in the natural fine aggregate.

The preparation method of the graded rubber concrete of above-mentioned continuous grain size, comprises the steps:

1) First, soak the rubber powder in 1M NaOH solution for 1 hour, and stir once every 10 minutes; then wash it several times with tap water until the pH value reaches about 7; finally, ventilate and dry the rubber powder for later use.

2) Randomly select 3 samples of 500g each of fine aggregate for sieving test, count the remaining percentage of each sieve hole, and then average the results obtained from the three tests to obtain the gradation curve of the fine aggregate in this test;

3) Sieve all the fine aggregates and divide them into 5 sections above 0-0.30mm, 0.30-0.60mm, 0.60-1.18mm, 1.18-2.36mm, and 2.36-4.75mm for later use.

4) The rubber powder with a particle size of 0-0.3mm and 0.3-0.6mm is quantitatively replaced in the 0-0.3mm and 0.3-0.6mm sections in 3), and then the fine aggregate is graded according to the gradation curve in 2) Mixing results in a graded fine aggregate containing rubber aggregates.

5) After weighing each raw material in proportion, add cement and fine aggregate containing rubber aggregates to a forced mixer and stir evenly, then add coarse aggregate and water in turn and stir evenly.

6) Put the concrete obtained in step 5) into a mold, place it on a vibrating table, vibrate evenly, and perform standard maintenance to obtain rubber concrete.

Example 2

A graded rubber concrete with continuous particle size and a preparation method thereof are the same as in Example 1, except that the particle size range of the selected rubber powder is different, and the particle size range of the rubber powder is 0.3-0.6mm, 0.6-1.18mm, Respectively replace the 0.3-0.6mm and 0.6-1.18mm sections in the natural fine aggregate.

Example 3

A graded rubber concrete with a continuous particle size and a preparation method thereof are the same as in Example 1, except that the selected rubber powder particle size ranges are different, and the rubber powder particle size ranges are 0.6-1.18mm and 1.18-2.36mm, Respectively replace the 0.6-1.18mm and 1.18-2.36mm sections in the natural fine aggregate.

Example 4

A graded rubber concrete with a continuous particle size and a preparation method thereof are the same as in Example 1, except that the selected rubber powder particle size ranges are different, and the rubber powder particle size ranges are 1.18-2.36mm and 2.36-4.75mm, Respectively replace the 1.18-2.36mm and 2.36-4.75mm sections in the natural fine aggregate.

The performance test results of the graded rubber concrete with fixed particle size prepared by different present embodiments are shown in Table 1 below:

The graded rubber concrete test result of the fixed particle diameter of table 1 embodiment 1-4

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting the protection scope of the present invention, although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand , the technical solution of the present invention may be modified or equivalently replaced without departing from the spirit and scope of the technical solution of the present invention.

Claims (8)

1. A graded rubber powder concrete of continuous particle size, is characterized in that, calculates according to parts by weight, comprises following raw material: 420 parts of cement, 553.5-615 parts of fine aggregate, 1194 parts of coarse aggregate, 24.78 parts of rubber powder and 210 parts of water; Among them, the particle size of rubber powder is 0-0.3mm, 0.3-0.6mm, respectively replacing the section of natural fine aggregate with particle size of 0-0.3mm, 0.3-0.6mm; or the particle size range of rubber powder is 0.3- 0.6mm, 0.6-1.18mm, respectively replacing the 0.3-0.6mm and 0.6-1.18mm sections of natural fine aggregate; or the particle size range of rubber powder is 0.6-1.18mm, 1.18-2.36mm, respectively replacing natural fine bone The 0.6-1.18mm, 1.18-2.36mm section in the material; or the particle size range of the rubber powder is 1.18-2.36mm, 2.36-4.75mm, respectively replacing the 1.18-2.36mm, 2.36-4.75mm section in the natural fine aggregate ; The graded rubber powder concrete with continuous particle size is prepared by the following preparation method, and the preparation method includes the following steps: (1) First soak the rubber powder in NaOH solution, then wash it with tap water until the pH value reaches 7, then ventilate and dry the rubber powder for later use; (2) Randomly select three fine aggregate samples of equal quality for sieving test, count the remaining percentage of each sieve hole, and then average the results obtained from the three tests to obtain the gradation curve of the fine aggregate in this test; (3) Weigh the required fine aggregate according to the amount for screening, and divide it into five sections according to 0-0.3mm, 0.3-0.6mm, 0.6-1.18mm, 1.18-2.36mm and 2.36-4.75mm; (4) Quantitatively weigh the rubber powder in the adjacent particle size range, and replace the corresponding particle size segment in the 5 segments in step (3) according to the particle size of the rubber powder, and then follow the gradation curve in step (2) mixing the fine aggregates according to the gradation to obtain gradation fine aggregates containing rubber aggregates; (5) Weigh the cement according to the amount, mix it with the graded fine aggregate containing rubber aggregates, add the forced mixer to stir evenly, then add the coarse aggregate weighed according to the amount, water and water reducing agent in turn, and stir evenly can; (6) Put the concrete obtained in step (5) into the mold and place it on a vibrating table, vibrate evenly and then perform standard curing to obtain rubber concrete. 2. The graded rubber powder concrete with continuous particle size according to claim 1, characterized in that the cement is P•O4 2.5 ordinary Portland cement. 3. A graded rubber powder concrete with continuous particle size according to claim 1, characterized in that the fine aggregate is graded medium sand in zone 2, and the fineness modulus is 2.69. 4. The graded rubber powder concrete with continuous particle size according to claim 1, characterized in that, the rubber powder is obtained by grinding waste tires, and the particle size range is 0-0.3mm, 0.3-0.6mm, 0.6mm Between -1.18mm, 1.18-2.36mm and 2.36-4.75mm. 5. The graded rubber powder concrete of a kind of continuous particle size according to claim 1, is characterized in that, described coarse aggregate is crushed stone, and maximum particle diameter is 20mm, wherein 5-10mm crushed stone 37%, 10 -20mm gravel 63%. 6. a preparation method of the gradation rubber powder concrete of continuous particle size described in any one of claim 1～5, is characterized in that, comprises the steps: (1) First soak the rubber powder in NaOH solution, then wash it with tap water until the pH value reaches 7, then ventilate and dry the rubber powder for later use; (2) Randomly select three fine aggregate samples of equal quality for sieving test, count the remaining percentage of each sieve hole, and then average the results obtained from the three tests to obtain the gradation curve of the fine aggregate in this test; (3) Weigh the required fine aggregate according to the amount for screening, and divide it into five sections according to 0-0.3mm, 0.3-0.6mm, 0.6-1.18mm, 1.18-2.36mm and 2.36-4.75mm; (4) Quantitatively weigh the rubber powder in the adjacent particle size range, and replace the corresponding particle size segment in the 5 segments in step (3) according to the particle size of the rubber powder, and then follow the gradation curve in step (2) mixing the fine aggregates according to the gradation to obtain gradation fine aggregates containing rubber aggregates; (5) Weigh the cement according to the amount, mix it with the graded fine aggregate containing rubber aggregates, add the forced mixer to stir evenly, then add the coarse aggregate weighed according to the amount, water and water reducing agent in turn, and stir evenly can; (6) Put the concrete obtained in step (5) into the mold and place it on a vibrating table, vibrate evenly and then perform standard curing to obtain rubber concrete. 7. the preparation method of the graded rubber powder concrete of a kind of continuous particle size according to claim 6, is characterized in that, the concentration of described NaOH solution is 1mol/L, adopts solid content to be 96% sodium hydroxide flake solid configuration. 8. The preparation method of a graded rubber powder concrete with continuous particle size according to claim 6, characterized in that the soaking time in the NaOH solution is 1 hour, and stirring once every 10 minutes.