CN112010608A - Manufacturing method of green high-ductility fiber concrete hollow building block - Google Patents

Abstract

The invention relates to a method for making green high ductility fiber concrete hollow blocks, which adopts high ductility fiber concrete as a raw material to make hollow blocks. The components of high ductility fiber concrete are cement, fly ash, mineral powder, sand, sisal fiber and water; among them, by mass percentage, cement: fly ash: mineral powder: sand: water=1:0.55~0.70 : 0.27~0.35: 0.73~0.9: 0.55~0.65; based on the total volume of cement, fly ash, mineral powder, sand and water mixed evenly, the volume content of sisal fiber is 0.2‑1%. The usage of industrial waste slag, slag powder and fly ash is relatively increased, and the relative reduction of cement usage is beneficial to the high ductility hollow block made which is green and environmentally friendly. Reasonable content of mineral powder and fly ash can effectively improve the ductility of cement base. Compared with pva, steel fiber is used as a raw material to provide bridging stress and prevent cracking. Sisal fiber is used as the main component to improve crack resistance, which has the characteristics of low cost and environmental protection. After sisal fiber is treated with alkali, Durability meets engineering needs.

Description

A kind of manufacturing method of green high ductility fiber reinforced concrete hollow block

technical field

The invention relates to a manufacturing method of a green high-ductility fiber concrete hollow block, and belongs to the technical field of building products.

Background technique

In the frame structure, although the infill wall is not the main force-bearing member of the structure, from the perspective of earthquake resistance, it acts as the first anti-seismic defense line and plays the role of dissipating seismic energy. More broadly, especially when the frame structure with infill walls resists lateral action, the energy absorbed by the infill walls cannot be ignored, and it is also beneficial to weaken the response of the main frame.

Infill walls in real structures are often made of ordinary concrete hollow blocks. However, ordinary concrete hollow blocks do not have tensile strain hardening properties, which leads to the phenomenon of low ductility of the infill wall, which leads to the phenomenon of low ductility of the infill wall when the infill wall is subjected to relatively high ductility. Large lateral action, such as earthquake action, often leads to the appearance of cracks. What's more, the cracks are large and wide, which can lead to the collapse of the infill wall in severe cases. Among them, the low ductility and insufficient deformation capacity of ordinary concrete hollow blocks are the important factors leading to this phenomenon.

To this end, it is necessary to provide a hollow block with tensile strain hardening properties, ductility significantly higher than ordinary concrete, and other performance indicators such as tensile strength, compressive strength, and durability equivalent to or even better than ordinary concrete. , its ductility is significantly higher than that of ordinary concrete.

SUMMARY OF THE INVENTION

In view of the deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a manufacturing method of a green high ductility fiber reinforced concrete hollow block.

In order to solve the above technical problems, the technical solution of the present invention is: a method for making green high ductility fiber reinforced concrete hollow blocks, using high ductility fiber reinforced concrete as a raw material to make hollow blocks.

Preferably, the minimum outer wall thickness of the hollow block is not less than 30mm, the minimum rib thickness is not less than 25mm, and the hollow ratio is not less than 25%.

Preferably, the components of the high ductility fiber concrete are cement, fly ash, mineral powder, sand, sisal fiber and water; wherein, by mass percentage, cement: fly ash: mineral powder: sand: water=1: 0.55~0.70:0.27~0.35:0.73~0.9:0.55~0.65; Based on the total volume of cement, fly ash, mineral powder, sand and water mixed evenly, the volume content of sisal fiber is 0.2-1% .

Preferably, the cement is PO 42.5 ordinary Portland cement; the fly ash is Class I fly ash; the loss on ignition of the mineral powder is less than 2.8%, the density is 3.07g/cm ³ , the water content is 6%, and the specific surface area is greater than 418m ² /kg; sand is quartz sand with a particle size of less than 0.3mm; the length of sisal fiber is 10~20mm, the diameter is 100~200μm, the density is 1.45g/cm, the elastic modulus of the material is 9.4~22GPa, and the elongation at break is about 6%, tensile strength 511-635Mpa, tensile elastic modulus 9.4-22.0GPa, Young's modulus 15GPa.

Preferably, the sisal fiber is subjected to alkali treatment to improve the durability of the sisal fiber in concrete, soaked in a 10% mass concentration of acrylic acid solution for 24 hours, and then pressed to dry and then naturally dried for use.

Preferably, TH-W5 superplasticizer with a water reducing rate of more than 30% is added to the high ductility fiber concrete, and the addition amount of the water reducing agent is 0.8% of the total mass of fly ash, mineral powder and cement.

Preferably, the preparation method of high ductility fiber concrete is as follows: dry and mix cement, silica fume, fly ash and sand evenly, add water reducing agent and 70% water, and mix evenly; then add sisal fiber and mix evenly, then add the remaining 30% water was mixed to obtain high ductility fiber reinforced concrete.

2)℃、相对湿度控制在(90+5)%，达到一定强度后出养护室，送进坯场进行自然养护至28d后得到成型的高延性空心砌块。Preferably, the preparation method of the hollow block is as follows: S1: using sisal fiber as a raw material to prepare high ductility fiber concrete mortar; S2: using high ductility fiber concrete mortar as a raw material to prepare a hollow block specimen; S3: using the prepared hollow block The block is placed in the steam curing room, and the temperature and humidity are controlled, and the temperature is controlled at (34

2) The temperature and relative humidity are controlled at (90+5)%. After reaching a certain strength, it is taken out of the curing room and sent to the billet yard for natural curing for 28 days to obtain the formed high ductility hollow block.

Compared with the prior art, the present invention has the following beneficial effects: the high ductility fiber concrete is used as the main raw material, the high strength and high toughness of the high ductility fiber concrete are fully utilized, the bearing capacity and ductility of the hollow block are improved, and the Seismic performance of block masonry structures.

The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

Description of drawings

FIG. 1 is a schematic structural diagram of an embodiment of the present invention.

Figure 2 is a schematic diagram of a uniaxial tensile test.

Figure 3 is a schematic diagram of the four-point bending test.

Detailed ways

In order to make the above-mentioned features and advantages of the present invention more obvious and easy to understand, the following specific embodiments are given and the accompanying drawings are described in detail as follows.

As shown in Figure 1-3, a method for making green high ductility fiber reinforced concrete hollow blocks uses high ductility fiber reinforced concrete as a raw material to make hollow blocks.

In the embodiment of the present invention, the minimum outer wall thickness of the hollow block should not be less than 30mm, the minimum rib thickness should be not less than 25mm, and the hollow ratio should not be less than 25%.

In the embodiment of the present invention, cement is an important raw material for making ordinary concrete blocks, and the use of a large amount of cement is often at the expense of sacrificing the environment. Therefore, if the usage of cement can be reduced, and the usage of industrial waste residues such as slag powder and fly ash can be added or increased, the usage of cement can be relatively reduced, which is beneficial to the high ductility hollow block produced as a green and environmentally friendly product. Therefore, the components of the high ductility fiber concrete of the present application are cement, fly ash, mineral powder, sand, sisal fiber and water; wherein, by mass percentage, cement: fly ash: mineral powder: sand: water= 1:0.55~0.70:0.27~0.35:0.73~0.9:0.55~0.65; Based on the total volume of cement, fly ash, mineral powder, sand and water mixed evenly, the volumetric dosage of sisal fiber is 0.2- 1%.

In the embodiment of the present invention, in order to improve the ductility of the block and achieve the characteristics of multi-crack development, the currently commonly used method is to mix pva fibers and steel fibers into cement-based materials to form high-ductility fiber concrete. However, the cost of pva fibers and steel fibers Too high should not be used in large quantities in concrete blocks. Taking into account factors such as ductility, cost, and striving for environmental protection, plant fiber (sisal fiber) is used as the raw material to improve the ductility of the block.

In the embodiment of the present invention, the cement is PO 42.5 ordinary Portland cement; the fly ash is Class I fly ash, and the main active chemical components are SiO2 and Al2O3, which can react with calcium hydroxide produced by cement hydration to form a gel The product plays the role of dense filling concrete; the loss on ignition of mineral powder is less than 2.8%, the density is 3.07g/cm ³ , the water content is 6%, and the specific surface area is greater than 418m ² /kg; the sand is quartz sand with a particle size of less than 0.3mm ; The length of sisal fiber is 10~20mm, the diameter is 100~200μm, the density is 1.45g/cm, the elastic modulus of the material is 9.4~22GPa, the elongation at break is about 6%, the tensile strength is 511~635Mpa, and the tensile elasticity Modulus 9.4~22.0GPa, Young's modulus 15GPa.

In the embodiment of the present invention, the sisal fiber is subjected to alkali treatment to improve the durability of the sisal fiber in concrete, soaked in a 10% acrylic emulsion solution for 24h, and then pressed to dry and then naturally dried for subsequent use. The solid content of the acrylic acid solution is very high, and it is easy to stick to each other after the fibers are soaked and pressed to dry. Therefore, the acrylic milk solution was diluted to 10% and used in the test.

In the embodiment of the present invention, TH-W5 high-efficiency water-reducing agent with a water-reducing rate of more than 30% is added to the high-ductility fiber concrete, and the addition amount of the water-reducing agent is 0.8 of the total mass of fly ash, mineral powder and cement. %. Its function is to disperse the cement particles through the physical and chemical action of the surface, thereby improving the fluidity of the matrix and reducing the water consumption.

In the embodiment of the present invention, the preparation method of high ductility fiber concrete is as follows: after dry mixing cement, silica fume, fly ash and sand evenly (about 2 minutes), adding water reducing agent and 70% water and stirring for 2 minutes; Then add sisal fiber and stir evenly (low speed for 4 minutes, high speed for 4 minutes), and finally add the remaining 30% of water and stir evenly to obtain high ductility fiber concrete.

2)℃、相对湿度控制在(90+5)%，达到一定强度后出养护室，送进坯场进行自然养护至28d后得到成型的高延性空心砌块。In the embodiment of the present invention, the preparation method of the hollow block is: S1: using sisal fiber as raw material to prepare high ductility fiber concrete mortar; S2: using high ductility fiber concrete mortar as raw material to prepare hollow block test piece; S3: The prepared hollow blocks were placed in a steam curing room, and the temperature and humidity were controlled, and the temperature was controlled at (34

2) The temperature and relative humidity are controlled at (90+5)%. After reaching a certain strength, it is taken out of the curing room and sent to the billet yard for natural curing for 28 days to obtain the formed high ductility hollow block.

In the embodiment of the present invention, the high ductility fiber reinforced concrete, the main raw material of the hollow block, has unique strain-hardening performance and strong toughness, and its ultimate tensile strain is greater than 1.5%, which overcomes many defects caused by the brittleness of the material; the high ductility fiber Concrete hollow blocks show the characteristics of multi-crack cracking. After the first crack of the material begins to occur, it will not gradually expand until it penetrates like ordinary concrete, but the number of cracks will continue to increase, but the width of the crack will not increase significantly. The multi-point cracking crack width in the saturated state is less than 50μm, so its excellent crack control ability is very beneficial to the requirements for crack width control of concrete hollow blocks, and effectively reduces the damage caused by cracks under earthquake action; sisal fiber cement-based material The bending resistance, toughness, flexural strength and deformation ability of the matrix material are significantly improved, and its compressive strength is improved to a certain extent. The high ductility fiber concrete adopted in the present invention can achieve compressive strength of 35-45Mpa, tensile strength of 4-5Mpa, and flexural strength of 7-9Mpa (about 50% higher than that without fibers), and has good mechanical properties. It is an ecological building material with high ductility, good durability (through alkalization treatment) and high damage resistance. It avoids brittle failure of blocks and can significantly improve the deformation ability and integrity of block masonry structures. The high ductility hollow block uses high ductility fiber reinforced concrete as the main raw material, which increases the bearing capacity, ductility and energy dissipation capacity of the block infill wall, and can be used as the first line of defense for the frame-infill wall system in the event of an earthquake. Improve the seismic performance and safety of the structure; price comparison, pva: 220,000/ton, domestic pva: 60,000/ton, ramie fiber (plant fiber): 52,000/ton, sisal fiber: 8,000/ton, so In the ratio of the high ductility fiber concrete, sisal fibers are used to replace steel fibers, PVA fibers, etc. to act as bridges, which greatly reduces the cost of traditional cement-based composite materials; the fiber-cement-based composite material of the present application uses a large amount of fly ash. Substitute some cement, reduce cement consumption, green economy and environmental protection. In general, because sisal fiber is relatively cheap and the amount of cement is reduced, the cost increase is relatively small compared to ordinary concrete blocks (500-600 yuan/cubic meter for sisal fiber cement-based composites, 300 yuan for ordinary concrete blocks). -400 yuan / cubic meter), but the ductility performance has been significantly improved.

Example 1:

Following the technical solution of the present invention, as shown in FIG. 1 , the size of the high ductility hollow block in this embodiment is 390mm×190mm×190mm, the outer wall thickness is 50mm, the rib is 45mm, and the hollow ratio is 29.76%.

The specific production process is as follows:

Step 1, using sisal fiber as raw material to prepare high ductility fiber concrete mortar:

The components of the high ductility fiber reinforced concrete mortar of this embodiment are: cement, fly ash, mineral powder, sand, sisal fiber and water, wherein, by mass percentage, cement: fly ash: mineral powder: sand: water =1:0.55:0.27:0.73:0.55; The total volume of cement, fly ash, mineral powder, sand and water mixed evenly is used as the base, and the volume content of sisal fiber is 0.5%; the cement is P. O42.5 ordinary Portland cement; the fly ash is Class I fly ash; the loss on ignition of the ore powder is less than 2.8%, the density is 3.07g/cm ³ , the water content is 6%, and the specific surface area is greater than 418m ² /kg; the sand is quartz sand with a particle size of less than 0.3 mm; the length of the sisal fiber is 10-20 mm, the diameter is 100-200 μm, the density is 1.45 g/cm, the elastic modulus of the material is 9.4-22 GPa, and it is fractured The elongation is about 6%, the tensile strength is 511-635Mpa, the tensile elastic modulus is 9.4-22.0GPa, and the Young's modulus is 15GPa. The sisal fiber should be treated with alkali to improve the durability of the sisal fiber in concrete. Soak in 10% acrylic milk solution for 24 hours, then press dry and then naturally dry for use. The solid content of the acrylic acid solution is very high, and it is easy to stick to each other after the fibers are soaked and pressed to dry. Therefore, the acrylic milk solution was diluted to 10% and used in the test. And the high ductility fiber reinforced concrete of this embodiment is added with TH-W5 superplasticizer with a water reducing rate of more than 30%, and the addition amount of the water reducing agent is 0.8% of the total mass of fly ash, mineral powder and cement. Among them, the water-cement ratio, water reducing agent and fiber dosage should be fine-tuned according to the actual situation of the site and the fluidity of the original fiber cement-based composite material.

The configuration process is as follows: firstly mix cement, mineral powder, fly ash and sand evenly (about 2 minutes), add water reducing agent and 70% water and mix for 2 minutes; then add sisal fiber and mix evenly (low speed for 4 minutes, High-speed for 4 minutes), and finally add 30% water and stir evenly to obtain high ductility fiber reinforced concrete.

Step 2, using high ductility fiber concrete as raw material, selecting a mold for ordinary concrete blocks with a size of 390mm × 190mm × 190mm, and using a domestic QKYM3-12 automatic block forming machine to prepare hollow block test pieces.

2)℃、相对湿度控制在(90+5)%，达到一定强度后出养护室，送进坯场进行自然养护至28d后得到成型的高延性空心砌块。Step 3, put the blank of the test piece together with the pallet into the steam curing room, control the temperature and humidity, and control the temperature at (34

2) The temperature and relative humidity are controlled at (90+5)%. After reaching a certain strength, it is taken out of the curing room and sent to the billet yard for natural curing for 28 days to obtain the formed high ductility hollow block.

In order to verify the mechanical properties of the high ductility blocks prepared by the present invention, the mechanical properties of the sisal-ECC obtained by the present invention were tested.

(1) Cube compression test

The cube compression test uses a 70.7mm × 70.7mm × 70.7mm test block. After 24 hours of molding, the test piece is demolded and placed in a standard curing room for 28 days. 3 hours before the test, it is taken out to dry for 3 hours to prepare for the test. Prepare 3 test blocks for each group of mix ratios to complete the compression test. The test indicators are elastic modulus and compressive strength.

(2) Uniaxial tensile test

The uniaxial tensile test uses a thickness × width × length = 50 mm × 50 mm × 190 mm test piece, the test piece is demolded after 24 hours, placed in a standard curing room for 28 days, and taken out to dry 3 hours before the test to prepare for the test. Four test blocks were prepared for each group of mix ratios to complete the tensile test. The test indicators are cracking strength, tensile strength, maximum tensile strain, elastic modulus and fracture energy. The crack development after the component test is shown in Figure 2.

(3) Four-point bending test

A 400mm×100mm×100mm test block was used for the bending test. The test piece was demolded after 24 hours, placed in a standard curing room for 28 days, and taken out to dry 3 hours before the test to prepare for the test. Prepare 3 test blocks for each set of mix ratios to complete the bending test. The test indicators are toughness index, peak load and flexural strength. The crack development of the specimen after the test is shown in Figure 3.

Sisal-ECC of the present invention utilizes the above-mentioned method to make test block, adopts the ratio of the concrete block of MU30 to make test piece, and tests under the same conditions, and the result is as shown in the following table:

Performance comparison table

The present invention is not limited to the above best embodiment, and anyone can come up with other various forms of green high ductility fiber reinforced concrete hollow block manufacturing methods under the inspiration of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims (8)

1. A method for manufacturing a green high-ductility fiber concrete hollow block is characterized by comprising the following steps: the hollow building block is made of high-ductility fiber concrete.

2. The method for manufacturing the green high-ductility fiber concrete hollow block according to claim 1, characterized in that: the minimum outer wall thickness of the hollow building block is not less than 30mm, the minimum rib thickness is not less than 25mm, and the hollow rate is not less than 25%.

3. The method for manufacturing the green high-ductility fiber concrete hollow block according to claim 1, characterized in that: the high-ductility fiber concrete comprises the components of cement, fly ash, mineral powder, sand, sisal fiber and water; wherein, the cement comprises fly ash, mineral powder, sand and water, the mass percentage is 1: 0.55-0.70: 0.27-0.35: 0.73-0.9: 0.55-0.65; based on the total volume of the cement, the fly ash, the mineral powder, the sand and the water after being uniformly mixed, the volume mixing amount of the sisal fibers is 0.2-1%.

4. The method for manufacturing the green high-ductility fiber concrete hollow block according to claim 3, characterized in that: the cement is P.O 42.5.5 ordinary portland cement; the fly ash is I-grade fly ash; the loss on ignition of the ore powder is less than 2.8 percent, and the density is 3.07g/cm³6 percent of water content and more than 418m of specific surface area²Per kg; the sand is quartz sand with the grain diameter smaller than 0.3 mm; the sisal fibers have a length of 10-20 mm, a diameter of 100-200 μm, a density of 1.45g/cm, an elastic modulus of 9.4-22 GPa, an elongation at break of about 6%, a tensile strength of 511-635 MPa, a tensile elastic modulus of 9.4-22.0 GPa, and a Young's modulus of 15 GPa.

5. The method for manufacturing the green high-ductility fiber concrete hollow block according to claim 4, characterized in that: the durability of the sisal fibers in concrete is improved by carrying out alkali treatment on the sisal fibers, the sisal fibers are soaked in a 10% propylene emulsion solution for 24 hours, and then the sisal fibers are naturally dried for later use after being pressed to dry.

6. The method for manufacturing the green high-ductility fiber concrete hollow block according to claim 4, characterized in that: the high-ductility fiber concrete is added with a TH-W5 high-efficiency water reducing agent with the water reducing rate of more than 30%, and the adding amount of the water reducing agent is 0.8% of the total mass of the fly ash, the mineral powder and the cement.

7. The method for manufacturing the green high-ductility fiber concrete hollow block according to claim 5, characterized in that: the preparation method of the high-ductility fiber concrete comprises the following steps: after the cement, the silica fume, the fly ash and the sand are uniformly dry-mixed, the water reducing agent and 70 percent of water are added and uniformly stirred; and then adding the sisal fibers, uniformly stirring, adding the rest 30% of water, and uniformly stirring to obtain the high-ductility fiber concrete.

8. The method for manufacturing the green high-ductility fiber concrete hollow block according to claim 1, characterized in that: the preparation method of the hollow building block comprises the following steps: s1: preparing high-ductility fiber concrete mortar by taking sisal fibers as raw materials; s2: preparing a hollow block test piece by using high-ductility fiber concrete mortar as a raw material; s3: placing the prepared hollow building blocks into a steam curing chamber, controlling the temperature and the humidity, and controlling the temperature to be (34)

2) Controlling the temperature and the relative humidity to be (90+5)%, taking out of a curing chamber after reaching certain strength, feeding into a stock ground, and naturally curing for 28 days to obtain the formed high-ductility hollow building block.

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