Processing technology of concrete doped with waste concrete blocks

Abstract

The invention provides a waste concrete block doped concrete processing technology which is characterized by comprising the following specific processing steps: S1, waste concrete pretreatment: collecting waste concrete and carrying out preliminary screening, and physically removing impurities, large fragments and non-recyclable parts in the waste concrete; s2, the waste concrete is crushed and screened, the screened waste concrete is crushed and crushed through a crusher, waste concrete blocks are crushed into small particles, and the particle size of the waste concrete is controlled to be 1-3 mm for standby application; and S3, cleaning and impurity removing treatment of the waste concrete, specifically, the concrete particles are subjected to water washing treatment through water washing equipment, and impurities with small sizes in the concrete particles are removed. Heavy metal and chemical components of the waste concrete are subjected to mixed treatment in the waste concrete treatment process, and the heavy metal and the chemical components in the concrete are fully treated in a physical and chemical combined mode.

Description

Technical Field

[0001] The invention relates to the technical field of waste concrete recycling, in particular to a concrete processing technology mixed with waste concrete blocks. Background Art

[0002] Waste concrete recycling refers to the treatment and processing of waste concrete to obtain reusable materials or products. Generally, waste concrete refers to waste concrete blocks, gravel, broken concrete, etc. generated in construction and infrastructure projects. Reusing waste concrete can reduce resource consumption and environmental impact and promote sustainable development. The goal of waste concrete recycling is to reduce the amount of waste, maximize the recycling and reuse of materials, reduce dependence on natural resources, and reduce negative impacts on the environment. Reusing waste concrete helps achieve the goals of circular economy and sustainable development. After the waste concrete is processed, it is added to new concrete for use to improve resource utilization.

[0003] However, the existing processing method of mixing waste concrete with new concrete for reuse has the following problems: waste concrete may contain pollutants and harmful substances, such as heavy metals and harmful chemicals, which may pose potential risks to the environment and human health. In addition, the indicators of waste concrete are different from those of new concrete, which may lead to insufficient fusion of concrete buildings and cracks during the fusion and user process. Therefore, it is necessary to design corresponding technical solutions to solve the existing technical problems. Summary of the invention

[0004] The purpose of the present invention is to provide a concrete processing technology for mixed waste concrete blocks, which solves the technical problem that waste concrete may contain pollutants and harmful substances, such as heavy metals and harmful chemicals, which may pose potential risks to the environment and human health. In addition, there are differences between the various indicators of waste concrete and those of new concrete, which may lead to insufficient fusion of concrete buildings and the generation of cracks during the fusion and user process.

[0005] To achieve the above object, the present invention provides the following technical solution: a concrete processing technology mixed with waste concrete blocks, the specific processing steps are as follows:

[0006] S1: Pretreatment of waste concrete: collecting waste concrete and conducting preliminary screening to physically remove debris, large pieces and non-reusable parts from the waste concrete;

[0007] S2: Waste concrete crushing and screening treatment, the screened waste concrete is crushed and broken through the crusher, the waste concrete blocks are broken into smaller particles, the particle size of the waste concrete is controlled to 1mm-3mm and is reserved;

[0008] S3: washing and removing impurities from the waste concrete, washing the concrete particles with water through a water washing device to remove impurities with smaller volume in the concrete particles, and after the removal is completed, introducing the washed concrete particles into a mixing container for standby use;

[0009] S4: Heavy metal and chemical component removal operation of waste concrete, using magnetic separation equipment, such as a magnetic separator, to remove waste concrete particles containing magnetic heavy metals, and introducing acidic solutions such as hydrochloric acid and sulfuric acid for pickling treatment to dissolve and remove heavy metals and harmful chemicals in the waste concrete, and then using alkaline solutions such as sodium hydroxide and calcium hydroxide for treatment, which can convert certain heavy metals and harmful chemicals into insoluble precipitates and remove them, to obtain concrete pre-finished products;

[0010] S5: Drying and refining of concrete pre-finished products. The concrete pre-finished products are introduced into the sintering equipment for high-temperature treatment. Through the high-temperature sintering process, harmful chemicals in the waste concrete are decomposed or converted into harmless substances, thereby removing them. After sintering, the concrete particles are naturally cooled. The cooled concrete particles are introduced into the crushing equipment for re-crushing treatment. The concrete particles are controlled to 0.5mm-0.9mm to obtain the finished product;

[0011] S6: nourishment treatment of finished concrete products, introduce the finished concrete into a mixing container and add surface treatment agent and admixtures into the mixing container. The admixtures are selected from water reducing agent, plasticizer, expansion agent, binder, and are fully mixed with concrete for use.

[0012] As a preferred embodiment of the present invention, the weight ratio includes 1200-1800 parts of coarse aggregate, 700-1000 parts of fine aggregate, 500-800 parts of processed waste concrete products, 350-550 parts of water, and 160-180 parts of admixtures.

[0013] As a preferred embodiment of the present invention, the steps of mixing the treated finished concrete with new concrete are as follows:

[0014] S7: Mixing and fusing the above two types of concrete, introducing the coarse aggregate, fine aggregate, processed waste concrete product, water and admixture into a concrete mixer according to the above proportions, and performing rotary mixing on each raw material by the concrete mixer to mix the raw materials into a slurry.

[0015] As a preferred embodiment of the present invention, S8: the concrete fusion degree is improved by the first level, the concrete slurry formed by mixing is introduced into a mixing container, cementitious material is added and fully mixed, the mixing speed is controlled at 1200r / min-1800r / min, the mixing temperature is controlled at 30℃-50℃, and the mixing time is controlled at 1h-2h, so that the cementitious material is fully integrated.

[0016] As a preferred method of the present invention, S9: secondary improvement treatment of concrete fusion degree, adding fiber materials such as polypropylene fiber, steel fiber, etc. to concrete can increase the toughness and crack resistance of concrete. The fiber materials can effectively disperse and absorb stress and reduce the formation and expansion of cracks.

[0017] As a preferred embodiment of the present invention, the fiber reinforcement is selected from one or more of polypropylene fiber and steel fiber.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention performs mixed treatment on heavy metals and chemical components of waste concrete during the treatment of waste concrete, uses magnetic separation equipment to remove waste concrete particles containing magnetic heavy metals, and introduces an acid solution for pickling treatment to dissolve and remove heavy metals and harmful chemicals in the waste concrete, and then uses an alkaline solution to convert certain heavy metals and harmful chemicals into insoluble precipitates and remove them, and adopts a combination of physical and chemical methods to fully treat the heavy metals and chemical components in the concrete. After the treatment is completed, the finished concrete is introduced into a mixing container and a surface treatment agent and an admixture are added into the mixing container, so as to improve the fusion effect of the two in the subsequent mixing process with new concrete, thereby ensuring the fusion degree and use effect of the two concretes.

[0020] 2. This solution improves the fusion degree for a second time when fusing the two types of concrete. By using cementitious materials and fiber materials, the fusion effect of the two types of concrete can be greatly improved, and the possibility of cracks occurring during use due to the difference in quality of the two types of concrete can be reduced. DETAILED DESCRIPTION

[0021] Embodiment 1:

[0022] A concrete processing technology mixed with waste concrete blocks, the specific processing steps are as follows:

[0023] S1: Pretreatment of waste concrete, collecting waste concrete and conducting preliminary screening to physically remove debris, large fragments and non-reusable parts from the waste concrete;

[0024] S2: Waste concrete crushing and screening treatment, the screened waste concrete is crushed and broken through the crusher, the waste concrete blocks are broken into smaller particles, the particle size of the waste concrete is controlled to 1mm-3mm and is reserved;

[0025] S3: washing and removing impurities from the waste concrete, washing the concrete particles with water through a water washing device to remove impurities with smaller volume in the concrete particles, and after the removal is completed, introducing the washed concrete particles into a mixing container for standby use;

[0026] S4: Heavy metal and chemical component removal operation of waste concrete, using magnetic separation equipment, such as a magnetic separator, to remove waste concrete particles containing magnetic heavy metals, and introducing acidic solutions such as hydrochloric acid and sulfuric acid for pickling treatment to dissolve and remove heavy metals and harmful chemicals in the waste concrete, and then using alkaline solutions such as sodium hydroxide and calcium hydroxide for treatment, which can convert certain heavy metals and harmful chemicals into insoluble precipitates and remove them, to obtain concrete pre-finished products;

[0027] S5: Drying and refining of concrete pre-finished products. The concrete pre-finished products are introduced into the sintering equipment for high-temperature treatment. Through the high-temperature sintering process, harmful chemicals in the waste concrete are decomposed or converted into harmless substances, thereby removing them. After sintering, the concrete particles are naturally cooled. The cooled concrete particles are introduced into the crushing equipment for re-crushing treatment. The concrete particles are controlled to 0.5mm to obtain the finished product;

[0028] S6: nourishment treatment of finished concrete products, introduce the finished concrete into a mixing container and add surface treatment agent and admixtures into the mixing container. The admixtures are selected from water reducing agent, plasticizer, expansion agent, binder, and are fully mixed with concrete for use.

[0029] The weight ratio includes 1,200 parts of coarse aggregate, 700 parts of fine aggregate, 500 parts of processed waste concrete products, 350 parts of water, and 160 parts of admixtures.

[0030] Steps for mixing treated concrete with new concrete:

[0031] S7: Mixing and fusing the above two types of concrete, introducing the coarse aggregate, fine aggregate, processed waste concrete product, water and admixture into a concrete mixer according to the above proportions, and performing rotary mixing on each raw material by the concrete mixer to mix the raw materials into a slurry.

[0032] S8: The first-level improvement treatment of concrete fusion degree is carried out. The concrete slurry formed by mixing is introduced into the mixing container, and the cementitious material is added and fully mixed. The mixing speed is controlled at 1200r / min, the mixing temperature is controlled at 30℃, and the mixing time is controlled at 1h, so that the cementitious material is fully integrated.

[0033] S9: Secondary improvement of concrete fusion degree. Adding fiber materials such as polypropylene fiber and steel fiber to concrete can increase the toughness and crack resistance of concrete. Fiber materials can effectively disperse and absorb stress and reduce the formation and expansion of cracks.

[0034] The present invention performs mixed treatment on heavy metals and chemical components of waste concrete during the treatment of waste concrete, uses magnetic separation equipment to remove waste concrete particles containing magnetic heavy metals, and introduces an acid solution for pickling treatment to dissolve and remove heavy metals and harmful chemicals in the waste concrete, and then uses an alkaline solution to convert certain heavy metals and harmful chemicals into insoluble precipitates and remove them, and adopts a combination of physical and chemical methods to fully treat the heavy metals and chemical components in the concrete. After the treatment is completed, the finished concrete is introduced into a mixing container and a surface treatment agent and an admixture are added into the mixing container, so as to improve the fusion effect of the two in the subsequent mixing process with new concrete, ensure the fusion degree and use effect of the two concretes, and when the two concretes are fused, the fusion degree is secondary improved, and the use effect of the fusion of the two concretes can be greatly improved by using cementitious materials and fiber materials, thereby reducing the possibility of cracks occurring during use due to the difference in quality of the two concretes.

[0035] Embodiment 2:

[0036] A concrete processing technology mixed with waste concrete blocks, the specific processing steps are as follows:

[0037] S1: Pretreatment of waste concrete, collecting waste concrete and conducting preliminary screening to physically remove debris, large fragments and non-reusable parts from the waste concrete;

[0038] S2: Waste concrete crushing and screening treatment, the screened waste concrete is crushed and broken through the crusher, the waste concrete blocks are broken into smaller particles, the particle size of the waste concrete is controlled to 1mm-3mm and is reserved;

[0039] S3: washing and removing impurities from the waste concrete, washing the concrete particles with water through a water washing device to remove impurities with smaller volume in the concrete particles, and after the removal is completed, introducing the washed concrete particles into a mixing container for standby use;

[0040] S4: Heavy metal and chemical component removal operation of waste concrete, using magnetic separation equipment, such as a magnetic separator, to remove waste concrete particles containing magnetic heavy metals, and introducing acidic solutions such as hydrochloric acid and sulfuric acid for pickling treatment to dissolve and remove heavy metals and harmful chemicals in the waste concrete, and then using alkaline solutions such as sodium hydroxide and calcium hydroxide for treatment, which can convert certain heavy metals and harmful chemicals into insoluble precipitates and remove them, to obtain concrete pre-finished products;

[0041] S5: Drying and refining of concrete pre-finished products. The concrete pre-finished products are introduced into the sintering equipment for high-temperature treatment. Through the high-temperature sintering process, harmful chemicals in the waste concrete are decomposed or converted into harmless substances, thereby removing them. After sintering, the concrete particles are naturally cooled. The cooled concrete particles are introduced into the crushing equipment for re-crushing treatment. The concrete particles are controlled to 0.7mm to obtain the finished product;

[0042] S6: nourishment treatment of finished concrete products, introduce the finished concrete into a mixing container and add surface treatment agent and admixtures into the mixing container. The admixtures are selected from water reducing agent, plasticizer, expansion agent, binder, and are fully mixed with concrete for use.

[0043] The weight ratio includes 1,500 parts of coarse aggregate, 850 parts of fine aggregate, 650 parts of processed waste concrete products, 480 parts of water, and 170 parts of admixtures.

[0044] Steps for mixing treated concrete with new concrete:

[0045] S7: Mixing and fusing the above two types of concrete, introducing the coarse aggregate, fine aggregate, processed waste concrete product, water and admixture into a concrete mixer according to the above proportions, and performing rotary mixing on each raw material by the concrete mixer to mix the raw materials into a slurry.

[0046] S8: The concrete fusion degree is improved at the first level. The concrete slurry formed by mixing is introduced into the mixing container, and the cementitious material is added and fully mixed. The mixing speed is controlled at 1500r / min, the mixing temperature is controlled at 40℃, and the mixing time is controlled at 1.5h, so that the cementitious material is fully integrated.

[0047] S9: Secondary improvement of concrete fusion degree. Adding fiber materials such as polypropylene fiber and steel fiber to concrete can increase the toughness and crack resistance of concrete. Fiber materials can effectively disperse and absorb stress and reduce the formation and expansion of cracks.

[0048] The present invention performs mixed treatment on heavy metals and chemical components of waste concrete during the treatment of waste concrete, uses magnetic separation equipment to remove waste concrete particles containing magnetic heavy metals, and introduces an acid solution for pickling treatment to dissolve and remove heavy metals and harmful chemicals in the waste concrete, and then uses an alkaline solution to convert certain heavy metals and harmful chemicals into insoluble precipitates and remove them, and adopts a combination of physical and chemical methods to fully treat the heavy metals and chemical components in the concrete. After the treatment is completed, the finished concrete is introduced into a mixing container and a surface treatment agent and an admixture are added into the mixing container, so as to improve the fusion effect of the two in the subsequent mixing process with new concrete, ensure the fusion degree and use effect of the two concretes, and when the two concretes are fused, the fusion degree is secondary improved, and the use effect of the fusion of the two concretes can be greatly improved by using cementitious materials and fiber materials, thereby reducing the possibility of cracks occurring during use due to the difference in quality of the two concretes.

[0049] Embodiment 3:

[0050] A concrete processing technology mixed with waste concrete blocks, the specific processing steps are as follows:

[0051] S1: Pretreatment of waste concrete: collecting waste concrete and conducting preliminary screening to physically remove debris, large pieces and non-reusable parts from the waste concrete;

[0052] S2: Waste concrete crushing and screening treatment, the screened waste concrete is crushed and broken through the crusher, the waste concrete blocks are broken into smaller particles, the particle size of the waste concrete is controlled to 1mm-3mm and is reserved;

[0053] S3: washing and removing impurities from the waste concrete, washing the concrete particles with water through a water washing device to remove impurities with smaller volume in the concrete particles, and after the removal is completed, introducing the washed concrete particles into a mixing container for standby use;

[0054] S4: Heavy metal and chemical component removal operation of waste concrete, using magnetic separation equipment, such as a magnetic separator, to remove waste concrete particles containing magnetic heavy metals, and introducing acidic solutions such as hydrochloric acid and sulfuric acid for pickling treatment to dissolve and remove heavy metals and harmful chemicals in the waste concrete, and then using alkaline solutions such as sodium hydroxide and calcium hydroxide for treatment, which can convert certain heavy metals and harmful chemicals into insoluble precipitates and remove them, to obtain concrete pre-finished products;

[0055] S5: Drying and refining of concrete pre-finished products. The concrete pre-finished products are introduced into the sintering equipment for high-temperature treatment. Through the high-temperature sintering process, harmful chemicals in the waste concrete are decomposed or converted into harmless substances, thereby removing them. After sintering, the concrete particles are naturally cooled. The cooled concrete particles are introduced into the crushing equipment for re-crushing treatment. The concrete particles are controlled to 0.9mm to obtain the finished product;

[0056] S6: nourishment treatment of finished concrete products, introduce the finished concrete into a mixing container and add surface treatment agent and admixtures into the mixing container. The admixtures are selected from water reducing agent, plasticizer, expansion agent, binder, and are fully mixed with concrete for use.

[0057] The weight ratio includes 1800 parts of coarse aggregate, 1000 parts of fine aggregate, 800 parts of processed waste concrete products, 550 parts of water, and 180 parts of admixtures.

[0058] Steps for mixing treated concrete with new concrete:

[0059] S7: Mixing and fusing the above two types of concrete, introducing the coarse aggregate, fine aggregate, processed waste concrete product, water and admixture into a concrete mixer according to the above proportions, and performing rotary mixing on each raw material by the concrete mixer to mix the raw materials into a slurry.

[0060] S8: The concrete fusion degree is improved at the first level. The concrete slurry formed by mixing is introduced into the mixing container, and the cementitious material is added and fully mixed. The mixing speed is controlled at 1800r / min, the mixing temperature is controlled at 50℃, and the mixing time is controlled at 2h, so that the cementitious material is fully integrated.

[0061] S9: Secondary improvement of concrete fusion degree. Adding fiber materials such as polypropylene fiber and steel fiber to concrete can increase the toughness and crack resistance of concrete. Fiber materials can effectively disperse and absorb stress and reduce the formation and expansion of cracks.

[0062] The present invention performs mixed treatment on heavy metals and chemical components of waste concrete during the treatment of waste concrete, uses magnetic separation equipment to remove waste concrete particles containing magnetic heavy metals, and introduces an acid solution for pickling treatment to dissolve and remove heavy metals and harmful chemicals in the waste concrete, and then uses an alkaline solution to convert certain heavy metals and harmful chemicals into insoluble precipitates and remove them, and adopts a combination of physical and chemical methods to fully treat the heavy metals and chemical components in the concrete. After the treatment is completed, the finished concrete is introduced into a mixing container and a surface treatment agent and an admixture are added into the mixing container, so as to improve the fusion effect of the two in the subsequent mixing process with new concrete, ensure the fusion degree and use effect of the two concretes, and when the two concretes are fused, the fusion degree is secondary improved, and the use effect of the fusion of the two concretes can be greatly improved by using cementitious materials and fiber materials, thereby reducing the possibility of cracks occurring during use due to the difference in quality of the two concretes.

[0063] Embodiment 4:

[0064] A concrete processing technology mixed with waste concrete blocks, the specific processing steps are as follows:

[0065] S1: Pretreatment of waste concrete: collecting waste concrete and conducting preliminary screening to physically remove debris, large pieces and non-reusable parts from the waste concrete;

[0066] S2: Waste concrete crushing and screening treatment, the screened waste concrete is crushed and broken through the crusher, the waste concrete blocks are broken into smaller particles, the particle size of the waste concrete is controlled to 1mm-3mm and is reserved;

[0067] S3: washing and removing impurities from the waste concrete, washing the concrete particles with water through a water washing device to remove impurities with smaller volume in the concrete particles, and after the removal is completed, introducing the washed concrete particles into a mixing container for standby use;

[0068] S4: Drying and refining of concrete pre-finished products. The concrete is introduced into the sintering equipment for high-temperature treatment. Through the high-temperature sintering process, harmful chemicals in the waste concrete are decomposed or converted into harmless substances, thereby removing them. After sintering, it is naturally cooled. The cooled concrete particles are introduced into the crushing equipment for re-crushing treatment. The concrete particles are controlled to 0.7mm to obtain the finished product;

[0069] The weight ratio includes 1,500 parts of coarse aggregate, 850 parts of fine aggregate, 650 parts of processed waste concrete products, 480 parts of water, and 170 parts of admixtures.

[0070] Steps for mixing treated concrete with new concrete:

[0071] S5: Mixing and fusing the above two types of concrete, introducing coarse aggregate, fine aggregate, processed waste concrete products, water and admixtures into a concrete mixer according to the above proportions, and performing rotary mixing on each raw material through the concrete mixer to mix the raw materials into a slurry.

[0072] According to the above four groups of embodiments, concrete was processed and laid, and the concrete laying effects produced by the concrete processing and laying methods adopted in each embodiment were observed, as follows:

[0073]

[0074] According to the above table, it can be found that the mixing method of waste concrete blocks and new concrete adopted in this scheme can effectively ensure the effect of concrete during use.

[0075] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A concrete processing process mixed with waste concrete blocks, characterized by: The specific processing steps are as follows: S1: Pretreatment of waste concrete: collecting waste concrete and conducting preliminary screening to physically remove debris, large pieces and non-reusable parts from the waste concrete; S2: Waste concrete crushing and screening treatment, the screened waste concrete is crushed and broken through the crusher, the waste concrete blocks are broken into smaller particles, the particle size of the waste concrete is controlled to 1mm-3mm and is reserved; S3: washing and removing impurities from the waste concrete, washing the concrete particles with water through a water washing device to remove impurities with smaller volume in the concrete particles, and after the removal is completed, introducing the washed concrete particles into a mixing container for standby use; S4: Heavy metal and chemical component removal operation of waste concrete, using magnetic separation equipment, such as a magnetic separator, to remove waste concrete particles containing magnetic heavy metals, and introducing acidic solutions such as hydrochloric acid and sulfuric acid for pickling treatment to dissolve and remove heavy metals and harmful chemicals in the waste concrete, and then using alkaline solutions such as sodium hydroxide and calcium hydroxide for treatment, which can convert certain heavy metals and harmful chemicals into insoluble precipitates and remove them, to obtain concrete pre-finished products; S5: Drying and refining of concrete pre-finished products. The concrete pre-finished products are introduced into the sintering equipment for high-temperature treatment. Through the high-temperature sintering process, harmful chemicals in the waste concrete are decomposed or converted into harmless substances, thereby removing them. After sintering, the concrete particles are naturally cooled. The cooled concrete particles are introduced into the crushing equipment for re-crushing treatment. The concrete particles are controlled to 0.5mm-0.9mm to obtain the finished product; S6: nourishment treatment of finished concrete products, introduce the finished concrete into a mixing container and add surface treatment agent and admixtures into the mixing container. The admixtures are selected from water reducing agent, plasticizer, expansion agent, binder, and are fully mixed with concrete for use.

2. The concrete mixed with waste concrete blocks according to claim 1, characterized in that: The weight ratio includes 1200-1800 parts of coarse aggregate, 700-1000 parts of fine aggregate, 500-800 parts of processed waste concrete products, 350-550 parts of water, and 160-180 parts of admixtures.

3. The concrete processing technology mixed with waste concrete blocks according to claim 1 is characterized by: Steps for mixing treated concrete with new concrete: S7: Mixing and fusing the above two types of concrete, introducing the coarse aggregate, fine aggregate, processed waste concrete product, water and admixture into a concrete mixer according to the above proportions, and performing rotary mixing on each raw material by the concrete mixer to mix the raw materials into a slurry.

4. The concrete processing technology mixed with waste concrete blocks according to claim 1 is characterized by: S8: The first-level improvement treatment of concrete fusion degree is carried out. The concrete slurry formed by mixing is introduced into the mixing container, and the cementitious material is added and fully mixed. The mixing speed is controlled at 1200r / min-1800r / min, the mixing temperature is controlled at 30℃-50℃, and the mixing time is controlled at 1h-2h, so that the cementitious material is fully integrated.

5. The concrete processing technology mixed with waste concrete blocks according to claim 1 is characterized by: S9: Secondary improvement of concrete fusion degree. Adding fiber materials such as polypropylene fiber and steel fiber to concrete can increase the toughness and crack resistance of concrete. Fiber materials can effectively disperse and absorb stress and reduce the formation and expansion of cracks.

6. The concrete processing technology mixed with waste concrete blocks according to claim 1 is characterized by: The fiber reinforcement is selected from one or more of polypropylene fiber and steel fiber.

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