Modified rubber concrete and preparation method thereof

Abstract

The invention relates to the field of green building materials in civil engineering, and discloses modified rubber concrete, which is prepared from the following materials in parts by weight: 456 parts of P.O 42.5 R ordinary Portland cement, 61 parts of fly ash, 625 parts of ordinary river sand, 16 parts of rubber particles, 1066 parts of coarse aggregate, 157 parts of ordinary tap water and 2.2 parts of polycarboxylic acid type high-efficiency water reducing agent. According to the modified rubber concrete and the preparation method thereof, the rubber particles are soaked in the 10% NaOH solution for 0.5 h in advance so as to remove various impurities attached to the surfaces of the rubber particles, the fly ash is doped, the concrete can be activated and filled, and the working performance of the modified rubber concrete is effectively improved. The slump of the modified rubber concrete reaches 200 mm, and the workability requirement of the modified rubber concrete is met.

Description

Technical Field

[0001] The invention relates to the field of green building materials for civil engineering and provides a modified rubber concrete and a preparation method thereof. Background Art

[0002] The rapid development of the automobile industry has caused the accumulation of large amounts of rubber waste to gradually evolve into an environmental problem that cannot be ignored. These rubber wastes degrade slowly in the natural environment and will cause black pollution to the ecological environment. Therefore, there is an urgent need to find new methods to recycle these rubber wastes. With the practice and application of ultra-high-strength concrete, people have found that even if the concrete meets the strength requirements, concrete structure damage will still occur, and it is a low-stress brittle fracture. Therefore, the brittleness of concrete has received more and more attention. In order to solve the above problems, people have been working hard to explore how to reduce the brittleness of concrete and improve its ductility through the modification of concrete materials. Studies have found that adding rubber particles to concrete can solve the above problems. Rubber concrete has shown many unique advantages that concrete does not have, such as light weight, elastic shock absorption, noise reduction and sound insulation, air permeability and water permeability, good ductility and toughness, etc.

[0003] Generally, rubber particles are added to concrete by replacing aggregates with equal volumes. A large number of studies have been conducted on rubber concrete at home and abroad. A large number of studies have shown that due to the complexity of the rubber recycling process, more impurities are often attached to its surface, and its apparent density is low, so it has poor adhesion with cement paste, resulting in reduced working performance. To this end, the present invention proposes a modified rubber concrete and a preparation method thereof. Summary of the invention

[0004] The purpose of the present invention is to provide a modified rubber concrete and a preparation method thereof, so as to solve the problem that the concrete in the prior art still suffers from low-stress brittle fracture when meeting the strength requirements.

[0005] To achieve the above purpose, the present invention adopts the following steps to achieve:

[0006] Step 1: Prepare the raw materials of modified rubber concrete, including the following weight ratio materials: 456 parts of PO 42.5R ordinary Portland cement, 61 parts of fly ash, 625 parts of ordinary river sand, 16 parts of rubber particles, 1066 parts of coarse aggregate, 157 parts of ordinary tap water, and 2.2 parts of polycarboxylic acid type high-efficiency water reducer. The polycarboxylic acid type high-efficiency water reducer accounts for 0.4% of the total mass of Portland cement and fly ash, and fly ash and ordinary Portland cement account for 23% of the total solid volume;

[0007] Step 2: Before the test, the rubber particles were soaked in 10% NaOH solution for 0.5 h;

[0008] Step 3: Pour the dry ingredients into the blender according to the proportion, start the blender and blend for two minutes;

[0009] Step 4: Add the water reducer to the weighed tap water, pour half of the water into the blender, start the blender and blend for three minutes;

[0010] Step 5: Pour the remaining water into the blender and start blending for three minutes.

[0011] Step 6: Finally, the formed modified rubber concrete is placed into the mold.

[0012] Preferably, the maximum thickness of the ordinary river sand is 5 mm and the bulk density is 1221.2 kg / m 3 .

[0013] Preferably, the coarse aggregate is continuously graded crushed stone with a particle size of 5-10 mm and a bulk density of 1442.5 kg / m 3 .

[0014] Preferably, the rubber particles have a particle size of 40 mesh, an average particle size of 425 μm, and a bulk density of 290.1 ​​kg / m 3 , replacing ordinary river sand at an equal volume replacement rate of 10%.

[0015] Preferably, the rubber particles are soaked in 10% NaOH solution for 0.5 h before use.

[0016] Compared with the prior art, the present invention has the following effects:

[0017] The modified rubber concrete and its preparation method use 10% NaOH solution to soak the rubber particles for 0.5 hours in advance to remove various impurities attached to the surface of the rubber particles, which helps to improve the bonding performance between the cement paste and the surface of the rubber particles.

[0018] Adding fly ash can activate and fill concrete, effectively improving the working performance of the modified rubber concrete. The slump of the modified rubber concrete proposed by the present invention reaches 200mm, meeting the working requirements of the modified rubber concrete. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with Example 1. The following Example 1 is only used to more clearly illustrate the technical solution of the present invention and should not be understood as being restrictive.

[0020] A modified rubber concrete and a preparation method thereof are achieved by the following steps:

[0021] Step 1: Prepare the raw materials of modified rubber concrete, including the following weight ratio materials: 456 parts of PO 42.5R ordinary Portland cement, 61 parts of fly ash, 625 parts of ordinary river sand, 16 parts of rubber particles, 1066 parts of coarse aggregate, 157 parts of ordinary tap water, and 2.2 parts of polycarboxylic acid type high-efficiency water reducer. The water-cement ratio is 0.3, the polycarboxylic acid type high-efficiency water reducer accounts for 0.4% of the total mass of Portland cement and fly ash, and the fly ash and ordinary Portland cement account for 23% of the total solid volume;

[0022] Step 2: Before the test, the rubber particles were soaked in 10% NaOH solution for 0.5 h;

[0023] Step 3: Pour the dry ingredients into the blender according to the proportion, start the blender and blend for two minutes;

[0024] Step 4: Add the water reducer to the weighed tap water, pour half of the water into the blender, start the blender and blend for three minutes;

[0025] Step 5: Pour the remaining water into the blender and start blending for three minutes.

[0026] Step 6: Finally, the formed modified rubber concrete is placed into the mold.

[0027] In order to compare the working performance of the modified rubber concrete, another embodiment 2 (ordinary concrete) was tested.

[0028] The following steps are adopted to implement Example 2:

[0029] Step 1: Prepare the raw materials of ordinary concrete, including the following weight ratio materials: 456 parts of PO 42.5R ordinary Portland cement, 61 parts of fly ash, 694 parts of ordinary river sand, 1066 parts of coarse aggregate, 157 parts of ordinary tap water, and 2.2 parts of polycarboxylic acid type high-efficiency water reducer. The water-cement ratio is 0.3, the polycarboxylic acid type high-efficiency water reducer accounts for 0.4% of the total mass of Portland cement and fly ash, and the fly ash and ordinary Portland cement account for 22% of the total solid volume;

[0030] The technical steps of Example 2 are the same as those of Example 1, except that Example 2 does not have step 2.

[0031] The test results of Example 1 and Example 2 are compared, as shown in the following table:

[0032] Slump Ultimate compressive strain Example 1 200 0.008 Example 2 180 0.0031

[0033] Compared with Example 2, the slump of the present invention is 200 mm, which meets the workability requirements of the modified rubber concrete. Compared with Example 2, the ultimate compressive strain of the present invention is higher, that is, the rubber concrete shows better toughness, which effectively improves the brittle failure problem of concrete.

[0034] The embodiments are only a part of the invention and are only used to demonstrate the use of the method and its improvements. For technicians engaged in this field, they can make appropriate improvements to the patent within the scope of protection of the invention without departing from the method of the patent.

Claims

1. A modified rubber concrete and a preparation method thereof, characterized in that: The invention comprises the following materials in weight ratio: 456 parts of P.O42.5R ordinary Portland cement, 61 parts of fly ash, 625 parts of ordinary river sand, 16 parts of rubber particles, 1066 parts of coarse aggregate, 157 parts of ordinary tap water, and 2.2 parts of polycarboxylic acid type high-efficiency water reducer. The polycarboxylic acid type high-efficiency water reducer accounts for 0.4% of the total mass of Portland cement and fly ash, and the fly ash and ordinary Portland cement account for 23% of the total solid volume. The modified rubber concrete and the preparation method thereof are characterized in that the rubber particles are soaked in 10% NaOH solution for 0.5h in advance.

2. The modified rubber concrete according to claim 1, characterized in that: The cement is in accordance with the national standard "General Portland Cement" (GB 175-2007), using PO 42.5R ordinary Portland cement.

3. The modified rubber concrete according to claim 1, characterized in that: Use ordinary river sand, medium sand, with a maximum particle size of 5mm and a bulk density of 1221.2kg / m 3 .

4. The modified rubber concrete according to claim 1, characterized in that: The coarse aggregate is continuously graded crushed stone with a particle size of 5-10 mm and a bulk density of 1442.5 kg / m 3 .

5. The modified rubber concrete according to claim 1, characterized in that: The rubber particles have a particle size of 40 mesh, an average particle size of 425 μm, and a bulk density of 290.1 ​​kg / m 3 .

6. The modified rubber concrete according to claim 1, characterized in that: Polycarboxylic acid type high efficiency water reducer is used.

7. The modified rubber concrete according to claim 1, characterized in that: The rubber particles need to be soaked in 10% NaOH solution for 0.5h before use.