CN104058661B - A kind of concrete hollow block adding waste tire rubber granule and preparation method thereof - Google Patents

Abstract

The invention discloses a concrete hollow block added with waste tire rubber particles and a preparation method thereof. The raw materials are 302-375 parts by weight of cement, 565.7-607.2 parts of medium-coarse river sand, and 1180-1180 parts of gravel and/or pebbles. 1300 parts, 21.8-59.3 parts of rubber particles, 2.385 parts of water reducer, 106-134 parts of water; the preparation method is as follows: first soak the rubber particles in 20% KOH solution for 20 minutes, then wash them with clean water, and then dry them to Saturated surface dry state; add medium-coarse river sand, cement, water reducing agent and rubber particles into the mixer and mix and stir; then add gravel and/or pebbles, add water and stir to make a mixed concrete slurry, put it into the molding machine for molding, and then sequentially After curing, demoulding, and then natural curing; the particle size of the above rubber particles is 0.1-5mm, and the gradation is reasonable. The hollow block prepared by the method of the present invention has good comprehensive properties such as thermal insulation, heat insulation, sound insulation, and light weight, and is suitable for use as a load-bearing block for buildings with different load-bearing strength requirements.

Description

Concrete hollow block added with waste tire rubber particles and preparation method thereof

technical field

The invention relates to a concrete hollow block and a preparation method thereof, in particular to a concrete hollow block added with waste tire rubber particles and a preparation method thereof.

Background technique

With the rapid development of the automobile industry, the recycling of increasing waste tires has become a major topic of international concern. my country is the world's largest rubber consumer and the world's largest tire supplier. From 2002 to 2012, my country's rubber consumption ranked first in the world for 11 consecutive years. Hundreds of millions of rubber tires are discarded every year. Since they cannot be degraded naturally, the recycling and recycling of waste tires has long become a very urgent environmental protection issue.

In recent years, my country has successively developed the application technology of rubber powder/granules in roads, railways, building materials and other aspects, and achieved certain positive results. Such as:

Chinese patent application CN102976686B discloses a method for burning-free bricks with waste rubber and fly ash as main raw materials. The production period of this non-burning brick preparation method is long, and the density of the prepared non-burning brick is also relatively large, and the thermal insulation performance is not particularly ideal.

Chinese patent application CN101857399A discloses a rubber-reinforced cement functional composite material and its preparation method, which uses waste rubber and cement or cement mortar as raw materials, and uses a coupling agent to apply a coupling adhesive to the surface of waste rubber particles and/or powder , and then blend waste rubber particles and/or powder with cement or cement mortar, then add water to the rubber-cement mixture and stir evenly, and then pave, press, demould, and maintain to obtain a functional composite material product. It is said that this composite material has high mechanical strength and good durability, and has the characteristics of noise reduction, sound insulation, high impact resistance, damping and vibration reduction, wear resistance, anti-static, waterproof, etc. It also has the advantages of heat insulation and environmental protection. .

In the preparation process of this composite material, on the one hand, since it needs to introduce a large amount of coupling agent (20-40% of the rubber weight) for rubber surface modification treatment, the rubber particle pretreatment process is complicated and the production cost is relatively On the other hand, this kind of waste tire recycling is used for the manufacture of boards. Compared with the waste tire recycling directly used for building structural materials, the total amount of waste tire recycling has a relatively large room for improvement. .

At present, the 390mm×190mm×190mm single-row hole concrete hollow block produced in China for masonry of load-bearing walls has a loose density of 1400kg/m ³ , a block weight of 17.0kg, a porosity of 49.7%, and a thermal conductivity of 1.0- 1.04W/m·K. The main disadvantages of this concrete hollow block are: high density, heavy weight, low porosity, and unsatisfactory thermal insulation and sound insulation effects.

And if the waste tire rubber particles with low density, porous, and good thermal insulation performance can be introduced into the concrete hollow block, on the one hand, the porosity inside the concrete hollow block can be greatly increased, and the weight of the block can be effectively reduced; on the other hand On the one hand, it can reduce the thermal conductivity of concrete hollow blocks and improve the comprehensive properties of concrete hollow blocks such as thermal insulation and sound insulation.

However, the introduction of rubber particles into concrete mortar will lead to a substantial reduction in the compressive strength of concrete hollow blocks. How to introduce rubber particle raw materials into concrete mortar to obtain good thermal insulation and sound insulation effects of concrete hollow blocks, sufficient porosity, and effectively reduce the loose density and block weight of concrete hollow blocks (standard block unit On the basis of block weight), it has become a hot topic to reduce the reduction of the compressive strength of concrete blocks due to the introduction of rubber particles.

Contents of the invention

One of the objectives of the present invention is to provide a concrete hollow block with waste tire rubber particles added which is easy and quick to construct, which has good comprehensive performances such as thermal insulation, heat insulation, sound insulation, light weight, and environmental protection, and is suitable for use as Load-bearing blocks for buildings with different load-bearing strength requirements.

The technical scheme adopted by the present invention to achieve the above object is a method for preparing concrete hollow blocks added with waste tire rubber particles. -607.2 parts, 1180-1300 parts of gravel and/or pebbles, 21.8-59.3 parts of rubber particles, 2.385 parts of water reducing agent, 106-134 parts of water;

The main performance indicators are as follows: the porosity is 50-60.2%, the thermal conductivity is 0.68-0.93W/m·K, the bulk density is 1173-1380kg/m ³ , and the average compressive strength is 7.5-13.0MPa.

The technical effect directly brought by the above technical solution is that the prepared concrete hollow block has good thermal insulation, heat insulation, sound insulation, light weight, environmental protection and other comprehensive properties, and is suitable for buildings with different load-bearing strength requirements. load-bearing blocks.

The second object of the present invention is to provide a method for preparing concrete hollow blocks with waste tire rubber particles added with simple process, low manufacturing cost and convenient construction.

The technical solution adopted by the present invention to achieve the above object is a preparation method of concrete hollow blocks added with waste tire rubber particles, characterized in that the preparation method comprises the following steps:

(1), first soak the rubber particles in 20% KOH solution for 20 minutes, wash them with clear water, and then dry them in the air to a saturated surface dry state;

(2) Add medium-coarse river sand, cement, water reducer and rubber particles into the mixer, mix and stir evenly;

(3) Stir while adding water until the cement mortar completely wraps the rubber particles;

(4), adding gravel and/or pebbles, stirring until uniform while adding water, to obtain a mixed concrete slurry;

(5) Put the concrete slurry into the molding machine for molding, then undergo curing, demoulding, and then curing under natural conditions;

The above-mentioned rubber granules are obtained by using waste tires as raw materials by crushing at room temperature. The particle size is 0.1-5mm, and the particle size distribution is as follows by weight: 5% of the particle size is 0.1-0.16mm, and the particle size is 0.16-0.315mm. mm accounted for 8%, the particle size of 0.315-0.63mm accounted for 15%, the particle size of 0.63-1.25mm accounted for 22%, the particle size of 1.25-2.5mm accounted for 30%, the particle size of 2.5-5mm accounted for 20%.

In the above technical solution, the rubber granules are produced by using waste tires as raw materials by normal temperature pulverization. The normal temperature pulverization method refers to a pulverization method of preparing rubber powder through mechanical action in an environment at normal temperature or slightly higher than normal temperature; the pulverization principle is to apply extrusion, grinding, shearing, tearing, etc. to rubber by machinery. Multiple physical forces to cut and crush the rubber of waste tires. The rubber particles produced by the normal temperature crushing method have the characteristics of large surface area, uneven surface and many burrs.

In the above technical scheme, the rubber particles are subjected to centrifugal vibration screening by laying multi-layer screens with sieve aperture sizes of 5mm, 2.5mm, 1.25mm, 0.63mm, 0.315mm, 0.160mm, and 0.100mm respectively on the centrifugal vibrating sieve bed. , for a reasonable gradation ratio.

In the tire production process, zinc stearate, which is also used as a lubricant, anti-sticking agent and vulcanization catalyst activator, is added to the rubber, and the zinc stearate is powdery and has a slippery feel. If it does not adhere to the surface of the rubber particles or The effective removal of residual zinc stearate will directly affect the bonding force between rubber particles and cement mortar. Therefore, in the above technical solution, 20% KOH solution is used to soak the crushed rubber particles at normal temperature. The specific soaking process is as follows:

(1) Configure 20% KOH solution, half of it is placed in the bucket, and the other half is reserved for subsequent addition;

(2) Add rubber particles in the KOH solution barrel and keep stirring;

(3) Continuously add the solution to be added during the stirring process, and keep vibrating;

(4) After soaking for 20 minutes, filter out the rubber particles, wash them with water, and then dry them in the sun until saturated.

The rubber particles soaked in 20% KOH solution, on the one hand, can effectively remove the zinc stearate attached or remaining on the surface;

On the other hand, soaking rubber particles in 20% KOH solution not only does not change the physical and mechanical properties of rubber particles, but can also improve the micro and macro properties of modified concrete: rubber particles soaked in 20% KOH solution, cement The bonding force between the mortar and the rubber particles is greatly enhanced, and the strength of the modified concrete hollow block can be increased by more than 30%.

That is, the rubber particles were soaked in 20% KOH solution for 20 minutes, and there was a significant modification effect: the results of the comparison experiments showed that the cement mortar mixed with rubber particles modified by using 20% KOH solution on the surface of the rubber particles Compared with the cement mortar directly mixed with rubber particles not modified by KOH solution, the slump can be increased by at least 26%.

During the immersion treatment, the following chemical reactions mainly occur:

Zn(C ₁₇ H ₃₅ COO) ₂ +KOH＝2K(C ₁₇ H ₃₅ COO)+K ₂ (Zn(OH) ₄ )

Since the products of the above chemical reaction: K(C ₁₇ H ₃₅ COO) and K ₂ (Zn(OH) ₄ , are both easily soluble in water, the subsequent water washing step can fully and effectively remove the K attached to the surface of the rubber particles. (C ₁₇ H ₃₅ COO), K ₂ (Zn(OH) ₄ , and residual KOH solution.

In summary, it can be seen that the technical effect directly brought by the above technical solution is,

1. Greatly improved the bonding ability and bonding fastness between waste tire rubber particles and cement mortar;

2. The whole preparation process is simple, the raw materials are easy to obtain and the manufacturing cost is low;

3. The prepared concrete hollow block has high compressive strength and can be used for building load-bearing walls of buildings with different load-bearing strength requirements.

Preferably, the above cement is P.O42.5R cement; the apparent density of medium-coarse river sand is 2590kg/m ³ ; the particle size of gravel and/or pebbles is continuous, and the apparent density is 2710kg/m ³ .

The technical effect directly brought by this optimal technical solution is that the purpose of using P.O42.5R cement is to further shorten the period of demoulding and maintenance;

Medium-coarse river sand with an apparent density of 2590kg/ ^m3 , and gravel and/or pebbles with a continuous particle size and an apparent density of 2710kg/ ^m3 are used to better match the particle size of 0.1- 5mm and particle size gradation by weight ratio: 5% of the particle size is 0.1-0.16mm, 8% of the particle size is 0.16-0.315mm, 15% of the particle size is 0.315-0.63mm. 22% are 0.63-1.25mm, 30% are 1.25-2.5mm, and 20% are 2.5-5mm. An organic combination is formed between the three, which is better for rubber particles. and medium-coarse river sand are evenly dispersed throughout the concrete mortar system;

And fine rubber particles and fine river sand can effectively fill the gaps between concrete mortar aggregates, further ensure the sufficient compacting effect of concrete mortar, and improve the compressive strength of the final concrete hollow block .

In summary, compared with the prior art, the preparation method of the concrete hollow block added with waste tire rubber particles and the prepared concrete hollow block of the present invention have the following beneficial effects:

1. The production equipment and process are simple and the manufacturing cost is low;

2. The prepared concrete hollow blocks have good thermal insulation, heat insulation, sound insulation, light weight, environmental protection and other comprehensive properties;

3. The bonding ability and bonding fastness between waste tire rubber particles and cement mortar are greatly improved, and the concrete hollow blocks prepared by the method of the present invention are suitable for use as load-bearing blocks of buildings with different load-bearing strength requirements.

detailed description

The present invention will be described in detail below in conjunction with the embodiments.

Example 1

Sequentially weigh/measure 375kg of P.O42.5R cement, 134kg of water, 607.2kg of medium-coarse river sand, 1180kg of gravel and/or pebbles; 21.8kg of continuously graded rubber particles, and 2.385kg of water reducing agent;

First soak the rubber particles in 20% KOH solution for 20 minutes, then wash them with water and dry them in the sun until saturated;

Add medium-coarse river sand, cement, water reducing agent and rubber particles into the mixer, add water and mix well;

Add crushed stones and/or pebbles and stir until a mixed concrete slurry is obtained; then put the concrete slurry into a molding machine for molding, and then undergo curing, demoulding, and curing under natural conditions to obtain concrete hollow blocks.

Test results: the minimum compressive strength of a single concrete hollow block is ≥ 11MPa, and the average compressive strength of 5 concrete hollow blocks is ≥ 13MPa, meeting the compressive standard for load-bearing blocks of strength grade MU10;

The average porosity of the concrete hollow block is 50%, the thermal conductivity is less than or equal to 0.93W/m·K, and the loose density is about 1380kg/m ³ .

Example 2

Weigh 360kg of ordinary portland cement with the label of 42.5, 129kg of water, 601.3kg of medium-coarse river sand, 1210kg of gravel and/or pebbles; 23.7kg of continuously graded rubber particles, and 2.385kg of water reducing agent;

All the other steps are the same as in Example 1.

Test results: the minimum compressive strength of a single concrete hollow block is ≥ 10.2MPa, and the average compressive strength of 5 concrete hollow blocks is ≥ 12.4MPa, meeting the compressive standard for load-bearing blocks of strength grade MU10.0;

The average porosity of the concrete hollow block is 52%, the thermal conductivity is less than or equal to 0.90W/m·K, and the loose density is about 1358kg/m ³ .

Example 3

Weigh 342kg of P.O42.5R cement, 122kg of water, 595.4kg of medium-coarse river sand, 1270kg of gravel and/or pebbles; 29.6kg of continuously graded rubber particles, and 2.385kg of water reducing agent;

All the other steps are the same as in Example 1.

Test results: the minimum compressive strength of a single concrete hollow block is ≥ 9.8MPa, and the average compressive strength of 5 concrete hollow blocks is ≥ 11.8MPa, meeting the compressive standard for load-bearing blocks of strength grade MU10.0;

The average porosity of the concrete hollow block is 53.3%, the thermal conductivity is less than or equal to 0.85W/m·K, and the loose density is about 1320kg/m ³ .

Example 4

Weigh 330kg of P.O42.5R cement, 118kg of water, 589.4kg of medium-coarse river sand, 1270kg of gravel and/or pebbles; 35.6kg of continuously graded rubber particles, and 2.385kg of water reducing agent;

All the other steps are the same as in Example 1.

Test results: the minimum compressive strength of a single concrete hollow block is ≥ 9.1MPa, and the average compressive strength of 5 concrete hollow blocks is ≥ 11.0MPa, meeting the compressive standard for load-bearing blocks of strength grade MU10.0;

The void rate of the concrete hollow block is about 55%, the thermal conductivity is less than or equal to 0.82W/m·K, and the loose density is about 1290kg/m ³ .

Example 5

Weigh in turn 325kg of ordinary Portland cement with a label of 42.5, 108kg of water, 583.5kg of medium-coarse river sand, 1300kg of gravel and/or pebbles; 41.5kg of continuously graded rubber particles, and 2.385kg of water reducing agent;

All the other steps are the same as in Example 1.

Test results: the minimum compressive strength of a single concrete hollow block is ≥ 8.6MPa, and the average compressive strength of 5 concrete hollow blocks is ≥ 10.3MPa, meeting the compressive standard for load-bearing blocks of strength grade MU10.0;

The void ratio of the concrete hollow block is about 56.8%, the thermal conductivity is less than or equal to 0.78W/m·K, and the loose density is about 1263kg/m ³ .

Example 6

Weigh 318kg of P.O42.5R cement, 106kg of water, 577.6kg of medium-coarse river sand, 1300kg of gravel and/or pebbles; 47.4kg of continuously graded rubber particles and 2.385kg of water reducing agent;

All the other steps are the same as in Example 1.

Test results: the minimum compressive strength of a single concrete hollow block is ≥ 7.9MPa, and the average compressive strength of 5 concrete hollow blocks is ≥ 9.2MPa, meeting the compressive standard for load-bearing blocks of strength grade MU7.5;

The void rate of the concrete hollow block is about 57.4%, the thermal conductivity is less than or equal to 0.75W/m·K, and the loose density is about 1238kg/m ³ .

Example 7

Weigh 310kg of P.O42.5R cement, 111kg of water, 571.7kg of medium-coarse river sand, 1250kg of gravel and/or pebbles; 53.3kg of continuously graded rubber particles, and 2.385kg of water reducing agent;

All the other steps are the same as in Example 1.

Test results: the minimum compressive strength of a single concrete hollow block is ≥ 6.5MPa, and the average compressive strength of 5 concrete hollow blocks is ≥ 8.0MPa, meeting the compressive standard for load-bearing blocks of strength grade MU7.5;

The void rate of the concrete hollow block is about 58.9%, the thermal conductivity is less than or equal to 0.71W/m·K, and the loose density is about 1206kg/m ³ .

Example 8

Weigh 302kg of P.O42.5R cement, 108kg of water, 565.7kg of medium-coarse river sand, 1250kg of gravel and/or pebbles; 59.3kg of continuously graded rubber particles, and 2.385kg of water reducing agent;

All the other steps are the same as in Example 1.

Test results: the minimum compressive strength of a single concrete hollow block is ≥ 6.0MPa, and the average compressive strength of 5 concrete hollow blocks is ≥ 7.5MPa, meeting the compressive standard for load-bearing blocks of strength grade MU7.5;

The void rate of the concrete hollow block is about 60.2%, the thermal conductivity is less than or equal to 0.75W/m·K, and the loose density is about 1173kg/m ³ .

It should be noted that, in the above-mentioned embodiment 1-embodiment 8, the "continuously graded rubber particles" referred to all refer to: the particle size is 0.1-5 mm, and the particle size gradation is respectively by weight ratio: particle size 5% is 0.1-0.16mm, 8% is 0.16-0.315mm, 15% is 0.315-0.63mm, 22% is 0.63-1.25mm, and 1.25 -2.5mm accounted for 30%, particle size of 2.5-5mm accounted for 20% of the rubber particles. The "rubber granules" mentioned above are all made from waste tires by crushing at room temperature.

Claims (2)

1. A preparation method for concrete hollow blocks adding waste tire rubber particles, characterized in that the parts by weight of the raw materials are 302-375 parts of cement, 565.7-607.2 parts of medium-coarse river sand, 1180 parts of gravel and/or pebbles -1300 parts, 21.8-59.3 parts of rubber particles, 2.385 parts of water reducing agent, 106-134 parts of water; The main performance indicators of the hollow block are as follows: the porosity is 50-60.2%, the thermal conductivity is 0.68-0.93W/m·K, the loose density is 1173-1380kg/m ³ , and the average compressive strength is 7.5-13.0MPa; The preparation method comprises the following steps: (1), first soak the rubber particles in 20% KOH solution for 20 minutes, wash them with clear water, and then dry them in the air to a saturated surface dry state; (2) Add medium-coarse river sand, cement, water reducer and rubber particles into the mixer, mix and stir evenly; (3) Stir while adding water until the cement mortar completely wraps the rubber particles; (4), adding gravel and/or pebbles, stirring until uniform while adding water, to obtain a mixed concrete slurry; (5) Put the concrete slurry into the molding machine for molding, then undergo curing, demoulding, and then curing under natural conditions; The above-mentioned rubber granules are obtained by crushing waste tires at room temperature with a particle size of 0.1-5mm and a particle size distribution by weight: 5% of the particle size is 0.1-0.16mm, and the particle size is 0.16-0.315mm. mm accounted for 8%, the particle size of 0.315-0.63mm accounted for 15%, the particle size of 0.63-1.25mm accounted for 22%, the particle size of 1.25-2.5mm accounted for 30%, the particle size of 2.5-5mm accounted for 20%. 2. the preparation method of the concrete hollow block that adds waste tire rubber particles according to claim 1, is characterized in that, described cement is P.O42.5R cement; The apparent density of the medium-coarse river sand is 2590kg/m ³ ; The crushed stones and/or pebbles have a continuous particle size distribution and an apparent density of 2710kg/m ³ .