CN110143795A - A kind of PVA fiber modified rubber concrete and preparation method thereof - Google Patents

Abstract

The invention discloses a PVA fiber modified rubber concrete and a preparation method thereof, comprising cement, fine aggregate, coarse aggregate, rubber particles, silica fume, expansion agent, PVA fiber, water and a water reducer; the cement , fine aggregate, coarse aggregate, rubber particles, silica fume, expansion agent, PVA fiber, water and water reducing agent are mixed according to a certain ratio to make concrete with an apparent density of 2300kg/m ³ to 2400kg/m ³ . The present invention utilizes the characteristics of PVA fibers to improve the bending and deformation resistance of rubber concrete, improve the mechanical properties of rubber concrete, thereby improving the performance of rubber concrete, and can play a role in reducing strength loss, improving toughness, preventing cracking and impermeability, and improving durability. , resulting in high-performance concrete.

Description

A kind of PVA fiber modified rubber concrete and preparation method thereof

technical field

The invention relates to concrete, in particular to a PVA fiber modified rubber concrete and a preparation method thereof.

Background technique

The rapid development of the automobile industry has made the problems of recycling and disposal of waste tires increasingly prominent. Scrap tires are a kind of solid waste, known as "black pollution". Its recycling and treatment technology has always been a worldwide problem, and it is also a problem in environmental protection. Using waste rubber particles as aggregates in cement concrete materials is a resource-saving and environmentally friendly way to utilize waste rubber, and it provides a new method for solving the inherent brittleness of concrete. Compared with asphalt concrete, rubber concrete has significantly higher rigidity and strength than the former, and has long fatigue life, good water resistance, excellent frost resistance and skid resistance, strong corrosion resistance, and better stability, and is more suitable for heavy traffic The pavement and airport runway have a wider range of applications. Compared with traditional concrete, rubber concrete has the characteristics of light weight, high toughness, more energy absorption, superior crack resistance, sound insulation, heat insulation, and strong earthquake resistance. These characteristics make rubber concrete widely used in the field of construction engineering. However, all experimental studies to date show that the addition of rubber particles significantly reduces the strength of cement-based materials. How to realize the crack resistance and toughening of cement-based materials without significantly negative impact on strength has become the technical key to the application of rubber particles in concrete.

Contents of the invention

The purpose of the present invention is to improve the flexural deformation resistance and impact toughness of rubber concrete and improve its strength to a certain extent, to provide a PVA fiber modified rubber concrete and a preparation method thereof. The present invention utilizes the characteristics of PVA fibers to improve the bending and deformation resistance of rubber concrete, improve the mechanical properties of rubber concrete, thereby improving the performance of rubber concrete, and can play a role in reducing strength loss, improving toughness, preventing cracking and impermeability, and improving durability. , resulting in high-performance concrete.

The technical scheme adopted in the present invention is: a kind of PVA fiber modified rubber concrete, including cement, fine aggregate, coarse aggregate, rubber particles, silica fume, expansion agent, PVA fiber, water and water reducing agent; The dosage of the concrete is 400kg/m ³ ~ 500kg/m ³ concrete, the dosage of the fine aggregate is 600kg/m ³ concrete ~ 800kg/m ³ concrete, the dosage of the coarse aggregate is 800kg/m ³ concrete ~ 1000kg /m ³ concrete, the amount of the rubber particles is 10% to 30% of the amount of fine aggregate, the amount of silica fume is 0% to 10% of the amount of cement, and the amount of the expansion agent is the 0% to 10% of the amount of cement, the amount of the PVA fiber is 0.5% to 2.0% of the amount of cement, the amount of water is 30% to 50% of the amount of cement, and the amount of the water reducer The dosage is 0.5% to 2.0% of the cement dosage, and the cement, fine aggregate, coarse aggregate, rubber particles, silica fume, expansion agent, PVA fiber, water and water reducing agent are mixed to form an apparent density of 2300kg/m ³ ~ 2400kg/m ³ concrete.

Further, the cement is ordinary Portland cement.

Further, the fine aggregate is medium sand with a fineness modulus of 2.3-3.0.

Further, the coarse aggregate is continuously graded gravel or river pebbles of 5 mm to 30 mm.

Further, the maximum particle size of the rubber particles is 2.5 mm, the average particle size is 1.05 mm, the density is 1120 kg/m ³ , the apparent density is 1050 kg/m ³ , and the water absorption rate is less than 10%.

Further, the average particle diameter of the silica fume is 0.1 μm˜0.3 μm.

Further, the expansion agent is a calcium sulfoaluminate concrete expansion agent that can be mixed with cement and water to generate ettringite through hydration reaction.

Further, the length of the PVA fiber is 5mm-20mm.

Further, the water reducer is polycarboxylate water reducer.

Another technical scheme adopted in the present invention is: the preparation method of above-mentioned a kind of PVA fiber modified rubber concrete, comprises the following steps:

Step 1, according to the amount of water and water reducer, prepare water and water reducer into a solution;

Step 2, according to the amount of PVA fiber, put the PVA fiber into the solution obtained in step 1, and use ultrasonic wave to disperse for several minutes;

Step 3: Pour cement, fine aggregate, coarse aggregate, rubber particles, silica fume and expansion agent according to the mixing ratio, and the solution containing PVA fiber dispersed in step 2 into the mixing pot, and pour it into the mold after stirring. , after curing for several days, PVA fiber modified rubber concrete was obtained.

The beneficial effect of the present invention is: in order to improve the bending deformation resistance and impact toughness of rubber concrete and improve its strength to a certain extent, the present invention provides a kind of PVA fiber modified rubber concrete and its preparation method, the present invention utilizes the PVA fiber The characteristics improve the bending and deformation resistance of rubber concrete, improve the mechanical properties of rubber concrete, thereby improving the performance of rubber concrete, and can play a role in reducing strength loss, improving toughness, preventing cracking and impermeability, and improving durability. performance concrete.

Description of drawings

Fig. 1 is the change figure of the compressive strength of PVA fiber modified rubber concrete and ordinary rubber concrete under different rubber content in the present invention.

Fig. 2 is the change figure of the flexural strength of PVA fiber modified rubber concrete and ordinary rubber concrete under different rubber content in the present invention.

Detailed ways

In order to further understand the invention content, characteristics and effects of the present invention, the following examples are given, and detailed descriptions are as follows in conjunction with the accompanying drawings:

A PVA fiber modified rubber concrete is made of cement, fine aggregate, coarse aggregate, rubber particles, silica fume, expansion agent, PVA fiber, water and water reducing agent. Wherein, the consumption of described cement is 400kg/m ³ concrete～500kg/m ³ concrete, the consumption of described fine aggregate is 600kg/m ³ concrete～800kg/m ³ concrete, the consumption of described coarse aggregate is 800kg/m 3 concrete. m ³ concrete to 1000kg/m ³ concrete, the amount of rubber particles is 10% to 30% of the amount of fine aggregate, the amount of silica fume is 0% to 10% of the amount of cement, and the expansion agent The amount of water is 0% to 10% of the amount of cement, the amount of PVA fiber is 0.5% to 2.0% of the amount of cement, and the amount of water is 30% to 50% of the amount of cement. The amount of the water reducer is 0.5% to 2.0% of the amount of the cement, and the cement, fine aggregate, coarse aggregate, rubber particles, silica fume, expansion agent, PVA fiber, water and water reducer are mixed to prepare into concrete with an apparent density of 2300kg/m ³ to 2400kg/m ³ .

The cement adopts ordinary Portland cement, and the quality indexes all meet the standards.

The fine aggregate is medium sand with a fineness modulus of 2.3-3.0.

The coarse aggregate is continuously graded gravel or river pebbles of 5 mm to 30 mm.

The rubber granules are mainly produced by processing various waste rubber materials, including waste rubber, rubber scraps, automobile cushion belts, automobile tires and other waste rubber raw materials. The rubber particles preferably used in the present invention have a maximum particle size of 2.5 mm, an average particle size of 1.05 mm, a density of 1120 kg/m ³ , an apparent density of 1050 kg/m ³ , and a water absorption rate of less than 10%.

As one of the "three industrial wastes", silica fume is used as a concrete admixture, which not only reduces the amount of cement used, but also effectively alleviates the energy problems, environmental pollution problems and resource depletion problems of the century, making concrete more green. , is more in line with the strategy of sustainable development. At the same time, the average particle size of the silica fume selected in the invention is 0.1 μm to 0.3 μm, which is two orders of magnitude lower than that of ordinary cement, which makes the silica fume selected in the present invention have High pozzolanic activity, the pozzolanic reaction acts as a micro-filler and refines the pores, thus making the structure of the hardened slurry dense. At the same time, due to the secondary hydration of silica fume, the new hydrated calcium silicate gel Blockage in the capillary pores makes the capillary pores smaller and discontinuous, greatly improving the properties of the rubber concrete such as compactness, strength, impermeability, and frost resistance. The addition of silica fume in the present invention makes each of the rubber concrete in the present invention The age compressive strength is increased by 5% to 15% compared with conventional rubber concrete.

Expansion agent refers to a material that can cause volume expansion through physical and chemical reactions, and its volume expansion can be used in many fields such as material production and silent blasting. One of the main reasons why the strength of rubber concrete decreases is because of the large number of air bubbles introduced when rubber is incorporated into the concrete. When the expansion agent is added, the expansion agent will cause a certain expansion inside the concrete, and a certain prestress will be generated inside, so that the air bubbles inside the concrete will be greatly reduced, and the compactness, strength, and impermeability of the rubber concrete will be greatly improved. performance. The expansion agent refers to a calcium sulfoaluminate concrete expansion agent, which is a concrete expansion agent that generates ettringite through hydration reaction after mixing with cement and water. The addition of the expansion agent in the present invention increases the compressive strength of the rubber concrete at various ages by 5% to 10% compared with conventional rubber concrete.

PVA fiber refers to polyvinyl alcohol fiber. PVA fiber refers to a synthetic fiber made of high-quality polyvinyl alcohol (PVA) with a high degree of polymerization and processed by specific advanced technology. Its main feature is high strength and high modulus. High, wear-resistant, acid and alkali resistance, good weather resistance, good affinity and combination with cement, gypsum and other substrates, and non-toxic, non-polluting, no damage to human skin, harmless to human body, is a new generation of high-tech One of the green building materials. The length of the PVA fiber is 5mm-20mm.

The water reducer is preferably a polycarboxylate high-performance water reducer, which is a water reducer with a higher water reducing rate, better slump retention performance, less drying shrinkage, and a certain air-entraining performance .

The preparation method of the above-mentioned PVA fiber-modified rubber concrete is as follows: in order to distribute the PVA fiber evenly in the concrete and make the PVA fiber exert its maximum effect, first, according to the amount of water and water-reducing agent, configure the water and water-reducing agent in a beaker Then, put the PVA fiber into the solution formed by water and water reducing agent, then put the beaker into the ultrasonic equipment and disperse it by ultrasonic wave for 15-30 minutes to fully disperse the PAV fiber; finally, mix the cement according to the mixing ratio , fine aggregate, coarse aggregate, rubber particles, silica fume and expansion agent, and the dispersed solution containing PVA fiber are poured into the stirring pot, stirred at a slow speed, poured into the mold and cast, and maintained for 28 days to prepare PVA Fiber modified rubber concrete.

Example 1

The amount of cement is 400kg/ ^m3 concrete, the amount of fine aggregate is 800kg/ ^m3 concrete, the amount of coarse aggregate is 1000kg/ ^m3 concrete, the amount of rubber particles is 80kg/ ^m3 concrete, and the amount of silica fume is 0kg/m ³ concrete, the amount of expansion agent is 0kg/m ³ concrete, the amount of PVA fiber with a length of 6mm is 3kg/m ³ concrete, the amount of water is 120kg/m ³ concrete, and the amount of water reducing agent is 2kg/m ³ concrete , Mix cement, fine aggregate, coarse aggregate, rubber particles, silica fume, expansion agent, PVA fiber, water and water reducing agent to make concrete with an apparent density of 2400kg/ ^m3 . The mix ratio has a lower amount of PVA fiber, and the cost is the cheapest. Compared with ordinary rubber concrete, its compressive strength is increased by 10%, and its flexural strength is increased by 100%.

Example 2

The amount of cement is 450kg/ ^m3 of concrete, the amount of fine aggregate is 700kg/ ^m3 of concrete, the amount of coarse aggregate is 900kg/ ^m3 of concrete, the amount of rubber particles is 140kg/ ^m3 of concrete, and the amount of silica fume is 5kg/m ³ concrete, the amount of expansion agent is 10kg/m ³ concrete, the amount of PVA fiber with a length of 12mm is 4.5kg/m ³ concrete, the amount of water is 135kg/m ³ concrete, the amount of water reducing agent is 4.5kg/m ³ Concrete, mix cement, fine aggregate, coarse aggregate, rubber particles, silica fume, expansion agent, PVA fiber, water and water reducer to make concrete with an apparent density of 2350kg/ ^m3 . The mix ratio has a moderate amount of PVA fiber, and the cost is low. Compared with ordinary rubber concrete, its compressive strength is increased by 15%, and its flexural strength is increased by 120%.

Example 3

The amount of cement is 500kg/m ³ concrete, the amount of fine aggregate is 600kg/m ³ concrete, the amount of coarse aggregate is 800kg/m ³ concrete, the amount of rubber particles is 25% of the amount of fine aggregate, silica fume The amount of concrete is 10kg/m3, the amount of expansion agent is 20kg/ ^{m3 of} concrete, the amount of PVA fiber with a length of 18mm is 6kg/ ^m3 of concrete, the amount of water is 200kg/ ^m3 of concrete, and the amount of water reducer is 8kg/m3 ³ Concrete, mix cement, fine aggregate, coarse aggregate, rubber particles, silica fume, expansion agent, PVA fiber, water and water reducer to make concrete with an apparent density of 2400kg/ ^m3 . This mix ratio has a large amount of PVA fiber and high cost. Compared with ordinary rubber concrete, its compressive strength is increased by 20%, and its flexural strength is increased by 140%.

In summary, since the rubber particles of ordinary rubber concrete do not chemically react with any substance in the concrete, their main function is physical filling, so that the concrete has functional properties such as high toughness, abrasion resistance, and high damping. However, due to the interface gap between rubber particles and concrete, the strength of concrete decreases rapidly, resulting in the inability to fully utilize its functional properties such as high toughness, abrasion resistance, and high damping. When a certain amount of PVA fiber is mixed in the rubber concrete, the PVA fiber is distributed in a disordered network in the concrete, and the overlapping of the fiber network between the interface cracks can act as a bridge for stress transmission. When the material is stressed, the rubber Both fiber and fiber can release stress concentration, delay the expansion of cracks, and improve the compressive strength of the material (as shown in Figure 1) and the flexural strength (as shown in Figure 2). This shows that when the PVA fiber is mixed into the rubber concrete, the network distribution of the PVA fiber in the concrete and the lap bridging between the interface cracks can play a significant role in crack resistance and improve the mechanical properties of the rubber concrete. Thereby improving the properties of rubber concrete can play a role in reducing strength loss, improving toughness, preventing cracking and impermeability, and improving durability, thereby making high-performance rubber concrete.

According to the characteristics of high tensile strength and high elastic modulus of PVA fiber, the present invention combines it with rubber particles to modify the concrete material, and obtains the effect of significantly improving the bending deformation resistance and impact toughness of the material, while the strength tends to decrease have been effectively mitigated.

Although the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments. The above-mentioned specific embodiments are only illustrative and not restrictive. Those of ordinary skill in the art Under the enlightenment of the present invention, people can also make many forms without departing from the purpose of the present invention and the scope of protection of the claims, and these all belong to the protection scope of the present invention.

Claims (10)

1. a kind of PVA fibre modification rubber concrete, which is characterized in that including cement, fine aggregate, coarse aggregate, rubber grain, silicon Ash, swelling agent, PVA fiber, water and water-reducing agent；The dosage of the cement is 400kg/m³Concrete~500kg/m³Concrete, institute The dosage for stating fine aggregate is 600kg/m³Concrete~800kg/m³Concrete, the dosage of the coarse aggregate are 800kg/m³Coagulation Soil~1000kg/m³Concrete, the dosage of the rubber grain are the 10%~30% of the fine aggregate dosage, the silicon ash Dosage is the 0%~10% of the cement consumption, and the dosage of the swelling agent is the 0%~10% of the cement consumption, described The dosage of PVA fiber is the 0.5%~2.0% of the cement consumption, the dosage of the water be the cement consumption 30%~ 50%, the dosage of the water-reducing agent is the 0.5%~2.0% of the cement consumption, by the cement, fine aggregate, coarse aggregate, rubber It is 2300kg/m that glue particle, silicon ash, swelling agent, PVA fiber, water and water-reducing agent, which are mixed and made into apparent density,³~2400kg/m³'s Concrete.

2. a kind of PVA fibre modification rubber concrete according to claim 1, which is characterized in that the cement is using general Logical portland cement.

3. a kind of PVA fibre modification rubber concrete according to claim 1, which is characterized in that the fine aggregate is thin Spend the middle sand of modulus 2.3~3.0.

4. a kind of PVA fibre modification rubber concrete according to claim 1, which is characterized in that the coarse aggregate is 5mm The rubble or cobble of~30mm continuous grading.

5. a kind of PVA fibre modification rubber concrete according to claim 1, which is characterized in that the rubber grain is most Big partial size is 2.5mm, average grain diameter 1.05mm, density 1120kg/m³, apparent density 1050kg/m³, water absorption rate is less than 10%.

6. a kind of PVA fibre modification rubber concrete according to claim 1, which is characterized in that the silicon ash is averaged Partial size is 0.1 μm~0.3 μm.

7. a kind of PVA fibre modification rubber concrete according to claim 1, which is characterized in that the swelling agent uses The calcium sulphoaluminate class cement expansive material of entringite is generated after capable of mixing and stirring with cement and water through hydration reaction.

8. a kind of PVA fibre modification rubber concrete according to claim 1, which is characterized in that the length of the PVA fiber Degree is 5mm~20mm.

9. a kind of PVA fibre modification rubber concrete according to claim 1, which is characterized in that the water-reducing agent uses Poly carboxylic acid series water reducer.

10. a kind of preparation method based on the described in any item PVA fibre modification rubber concretes of the claims 1 to 9, It is characterized in that, comprising the following steps:

Step 1, according to the dosage of water and water-reducing agent, water and water-reducing agent are configured to solution；

Step 2, according to the dosage of PVA fiber, PVA fiber is put into the solution that step 1 obtains, and if being dispersed using ultrasonic wave Dry minute；

It step 3, will be after cement, fine aggregate, coarse aggregate, rubber grain, silicon ash and swelling agent and step 2 dispersion by match ratio Solution containing PVA fiber pours into agitated kettle, and stirring after-pouring pouring molding into mold obtains PVA after conserving several days Fibre modification rubber concrete.