High-strength recycled concrete and preparation method thereof
阅读说明：本技术 一种高强度再生混凝土及其制备方法 (High-strength recycled concrete and preparation method thereof ) 是由 刘满娇 于 2021-10-25 设计创作，主要内容包括：本发明公开了一种高强度再生混凝土及其制备方法,其原料如下：水泥、废旧钢筋、电熔镁砂、再生骨料、增强剂、聚羧酸高效减水剂,其制备方法包括预处理、截断和破碎处理、第一次混合、第二次混合、成品。与现有技术相比,本发明实施例1-5制备的混凝土,各项性能优越,显气孔率、抗折强度、抗压强度、线变化率等参数均出现较好的显著性差异。本发明在现有的再生混凝土的基础上,添加电熔镁砂、改良的再生骨料及全新的增强剂,同时设置两次混合方式,各个参数条件之间协同增效,赋予混凝土新的优异性能,不仅改变了混凝土内部的组织结构,提高了可施工性,而且极大提高了混凝土的强度。(The invention discloses high-strength recycled concrete and a preparation method thereof, wherein the high-strength recycled concrete comprises the following raw materials: the preparation method of the high-efficiency polycarboxylic acid water reducing agent comprises the steps of pretreatment, truncation and crushing treatment, primary mixing, secondary mixing and finished product forming. Compared with the prior art, the concrete prepared in the embodiments 1 to 5 of the invention has excellent performances, and has better significant differences in parameters such as apparent porosity, flexural strength, compressive strength, linear change rate and the like. On the basis of the existing recycled concrete, the invention adds the fused magnesia, the improved recycled aggregate and the brand-new reinforcing agent, simultaneously sets two mixing modes, realizes the synergistic interaction among all parameter conditions, endows the concrete with new excellent performance, not only changes the internal organization structure of the concrete, improves the constructability, but also greatly improves the strength of the concrete.)
1. A high-strength recycled concrete is characterized in that,
the composite material comprises the following raw materials in parts by weight:
2. the high strength recycled concrete of claim 1,
the composite material comprises the following raw materials in parts by weight:
3. the high strength recycled concrete of claim 2,
the composite material comprises the following raw materials in parts by weight:
4. the high strength recycled concrete of claim 1,
the cement is common Portland cement 42.5;
the waste steel bars are subjected to rust removing treatment in advance;
the particle size range of the fused magnesia is 4mm-8 mm.
5. The high strength recycled concrete of claim 1,
the preparation method of the recycled aggregate comprises the following steps:
selecting sand river crushed stone, crushing to 5-8 mm, soaking in 10% polyvinyl alcohol solution, and air drying.
6. The high strength recycled concrete of claim 1,
the reinforcing agent comprises triethanolamine, propylene carbonate, gypsum and slag,
the dosage ratio of the triethanolamine, the propylene carbonate, the gypsum and the slag is 1: 5: 3: 2.
7. a method of preparing the high strength recycled concrete of claim 1, comprising the steps of:
(1) pretreatment: preparing cement, waste steel bars, fused magnesia, recycled aggregate, a reinforcing agent and a carboxylic acid high-efficiency water reducing agent, and conveying the mixture to a shade drying place for storage;
(2) cutting and crushing: selecting waste steel bars and fused magnesia, cutting the waste steel bars, and crushing the fused magnesia;
(3) mixing for the first time: selecting cement, recycled aggregate, a carboxylic acid high-efficiency water reducing agent and water to carry out primary mixing treatment;
(4) and (3) mixing for the second time: selecting waste steel bars, fused magnesia and a reinforcing agent for second mixing;
(5) and (3) finished product: and after the second mixing, spraying water for curing, and reducing the temperature to room temperature.
8. The method for producing high-strength recycled concrete according to claim 7,
the length range of the waste steel bars cut in the step (2) is 1cm-2 cm;
the granularity range of the crushed fused magnesia in the step (2) is 0.5mm-0.6 mm.
9. The method for producing high-strength recycled concrete according to claim 7,
the temperature of the first mixing in the step (3) is 60-80 ℃, the time of the first mixing is 2h, and the stirring speed of the first mixing is 300 r/min.
10. The method for producing high-strength recycled concrete according to claim 7,
the temperature of the second mixing in the step (4) is 50-60 ℃, the time of the second mixing is 6h, and the stirring speed of the second mixing is 500 r/min.
Technical Field
The invention relates to the technical field of concrete, in particular to high-strength recycled concrete and a preparation method thereof.
Background
With the development of society, various buildings and construction projects are increasing, and concrete members are widely applied to pole tower structures, industrial plants and columns and foundation piles of civil buildings. Along with the transformation of cities, a large amount of waste buildings in the cities form construction wastes, and the treatment of the construction wastes not only needs a large-area storage yard, but also costs a large amount of manpower and material resources. With the development of construction science, effective utilization of construction waste becomes a new topic.
Construction waste formed by waste building concrete is crushed to form recycled concrete for recycling, so that a large amount of construction waste is treated, and construction materials are saved. However, the edges and corners of the recycled concrete aggregate obtained by crushing the waste concrete and the waste bricks are too many, most recycled aggregates are needle-shaped, micro cracks can be generated in the aggregates in the crushing process of the recycled aggregates, and the strength and the durability of the recycled concrete are low, so that the recycled concrete is mostly used in the field of non-structural non-load-bearing concrete such as backfill, roadbed and the like at present. The utilization rate of the recycled concrete is very low due to the limitation of the application field. The low mechanical properties of the recycled concrete become a bottleneck restricting the application of the recycled concrete.
Disclosure of Invention
Compared with the prior art, the concrete prepared by the invention has excellent performances, and has better significant differences in parameters such as apparent porosity, flexural strength, compressive strength, linear change rate and the like. On the basis of the existing recycled concrete, the invention adds the fused magnesia, the improved recycled aggregate and the brand-new reinforcing agent, simultaneously sets two mixing modes, realizes the synergistic interaction among all parameter conditions, endows the concrete with new excellent performance, not only changes the internal organization structure of the concrete, improves the constructability, but also greatly improves the strength of the concrete.
In order to achieve the purpose, the invention provides high-strength recycled concrete which comprises the following raw materials in parts by weight:
in the high-strength recycled concrete as described above,
the composite material comprises the following raw materials in parts by weight:
in the high-strength recycled concrete as described above,
the composite material comprises the following raw materials in parts by weight:
in the high-strength recycled concrete as described above,
the cement is common Portland cement 42.5;
the waste steel bars are subjected to rust removing treatment in advance;
the particle size range of the fused magnesia is 4mm-8 mm.
It should be noted that the polycarboxylate superplasticizer was purchased from Oster group Ltd, model number HSC-103.
In the high-strength recycled concrete as described above,
the preparation method of the recycled aggregate comprises the following steps:
selecting sand river crushed stone, crushing to 5-8 mm, soaking in 10% polyvinyl alcohol solution, and air drying.
In the high-strength recycled concrete as described above,
the reinforcing agent comprises triethanolamine, propylene carbonate, gypsum and slag,
the dosage ratio of the triethanolamine, the propylene carbonate, the gypsum and the slag is 1: 5: 3: 2.
a preparation method of the high-strength recycled concrete comprises the following steps:
(1) pretreatment: preparing cement, waste steel bars, fused magnesia, recycled aggregate, a reinforcing agent and a carboxylic acid high-efficiency water reducing agent, and conveying the mixture to a shade drying place for storage;
(2) cutting and crushing: selecting waste steel bars and fused magnesia, cutting the waste steel bars, and crushing the fused magnesia;
(3) mixing for the first time: selecting cement, recycled aggregate, a carboxylic acid high-efficiency water reducing agent and water to carry out primary mixing treatment;
(4) and (3) mixing for the second time: selecting waste steel bars, fused magnesia and a reinforcing agent for second mixing;
(5) and (3) finished product: and after the second mixing, spraying water for curing, and reducing the temperature to room temperature.
In the above-mentioned method for producing high-strength recycled concrete,
the length range of the waste steel bars cut in the step (2) is 1cm-2 cm;
the granularity range of the crushed fused magnesia in the step (2) is 0.5mm-0.6 mm.
In the above-mentioned method for producing high-strength recycled concrete,
the temperature of the first mixing in the step (3) is 60-80 ℃, the time of the first mixing is 2h, and the stirring speed of the first mixing is 300 r/min.
In the above-mentioned method for producing high-strength recycled concrete,
the temperature of the second mixing in the step (4) is 50-60 ℃, the time of the second mixing is 6h, and the stirring speed of the second mixing is 500 r/min.
The high-strength recycled concrete and the preparation method thereof provided by the technical scheme have the following beneficial effects:
compared with the prior art, the concrete prepared in the embodiments 1 to 5 of the invention has excellent performances, and has better significant differences in parameters such as apparent porosity, flexural strength, compressive strength, linear change rate and the like. On the basis of the existing recycled concrete, the invention adds the fused magnesia, the improved recycled aggregate and the brand-new reinforcing agent, simultaneously sets two mixing modes, realizes the synergistic interaction among all parameter conditions, endows the concrete with new excellent performance, not only changes the internal organization structure of the concrete, improves the constructability, but also greatly improves the strength of the concrete.
Drawings
FIG. 1 is a schematic flow chart of a method for producing high-strength recycled concrete according to an embodiment of the present invention.
Detailed Description
The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.
Example 1
The high-strength recycled concrete comprises the following raw materials in parts by weight:
in the high-strength recycled concrete as described above,
the cement is common Portland cement 42.5;
the waste steel bars are subjected to rust removing treatment in advance;
the particle size range of the fused magnesia is 4 mm.
In the high-strength recycled concrete as described above,
the preparation method of the recycled aggregate comprises the following steps:
selecting sand river crushed stone, crushing to 5mm, then soaking in a polyvinyl alcohol solution with the mass concentration of 10%, and airing.
In the high-strength recycled concrete as described above,
the reinforcing agent comprises triethanolamine, propylene carbonate, gypsum and slag,
the dosage ratio of the triethanolamine, the propylene carbonate, the gypsum and the slag is 1: 5: 3: 2.
the preparation method of the high-strength recycled concrete, as shown in fig. 1, comprises the following steps:
(1) pretreatment: preparing cement, waste steel bars, fused magnesia, recycled aggregate, a reinforcing agent and a carboxylic acid high-efficiency water reducing agent, and conveying the mixture to a shade drying place for storage;
(2) cutting and crushing: selecting waste steel bars and fused magnesia, cutting the waste steel bars, and crushing the fused magnesia;
(3) mixing for the first time: selecting cement, recycled aggregate, a carboxylic acid high-efficiency water reducing agent and water to carry out primary mixing treatment;
(4) and (3) mixing for the second time: selecting waste steel bars, fused magnesia and a reinforcing agent for second mixing;
(5) and (3) finished product: and after the second mixing, spraying water for curing, and reducing the temperature to room temperature.
In the above-mentioned method for producing high-strength recycled concrete,
the length range of the waste steel bars cut in the step (2) is 1 cm;
the granularity range of the fused magnesia after being crushed in the step (2) is 0.5 mm.
In the above-mentioned method for producing high-strength recycled concrete,
the temperature of the first mixing in the step (3) is 60 ℃, the time of the first mixing is 2 hours, and the stirring speed of the first mixing is 300 r/min.
In the above-mentioned method for producing high-strength recycled concrete,
and (4) the temperature of the second mixing in the step (4) is 50 ℃, the time of the second mixing is 6 hours, and the stirring speed of the second mixing is 500 r/min.
Example 2
The high-strength recycled concrete comprises the following raw materials in parts by weight:
in the high-strength recycled concrete as described above,
the cement is common Portland cement 42.5;
the waste steel bars are subjected to rust removing treatment in advance;
the particle size range of the fused magnesia is 8 mm.
In the high-strength recycled concrete as described above,
the preparation method of the recycled aggregate comprises the following steps:
selecting sand river crushed stone, crushing to 8mm, then soaking in a polyvinyl alcohol solution with the mass concentration of 10%, and airing.
In the high-strength recycled concrete as described above,
the reinforcing agent comprises triethanolamine, propylene carbonate, gypsum and slag,
the dosage ratio of the triethanolamine, the propylene carbonate, the gypsum and the slag is 1: 5: 3: 2.
the preparation method of the high-strength recycled concrete comprises the following steps:
(1) pretreatment: preparing cement, waste steel bars, fused magnesia, recycled aggregate, a reinforcing agent and a carboxylic acid high-efficiency water reducing agent, and conveying the mixture to a shade drying place for storage;
(2) cutting and crushing: selecting waste steel bars and fused magnesia, cutting the waste steel bars, and crushing the fused magnesia;
(3) mixing for the first time: selecting cement, recycled aggregate, a carboxylic acid high-efficiency water reducing agent and water to carry out primary mixing treatment;
(4) and (3) mixing for the second time: selecting waste steel bars, fused magnesia and a reinforcing agent for second mixing;
(5) and (3) finished product: and after the second mixing, spraying water for curing, and reducing the temperature to room temperature.
In the above-mentioned method for producing high-strength recycled concrete,
the length range of the waste steel bars cut in the step (2) is 2 cm;
the granularity range of the fused magnesia after being crushed in the step (2) is 0.6 mm.
In the above-mentioned method for producing high-strength recycled concrete,
the temperature of the first mixing in the step (3) is 80 ℃, the time of the first mixing is 2 hours, and the stirring speed of the first mixing is 300 r/min.
In the above-mentioned method for producing high-strength recycled concrete,
in the step (4), the temperature of the second mixing is 60 ℃, the time of the second mixing is 6 hours, and the stirring speed of the second mixing is 500 r/min.
Example 3
The high-strength recycled concrete comprises the following raw materials in parts by weight:
in the high-strength recycled concrete as described above,
the cement is common Portland cement 42.5;
the waste steel bars are subjected to rust removing treatment in advance;
the particle size range of the fused magnesia is 4 mm.
In the high-strength recycled concrete as described above,
the preparation method of the recycled aggregate comprises the following steps:
selecting sand river crushed stone, crushing to 5mm, then soaking in a polyvinyl alcohol solution with the mass concentration of 10%, and airing.
In the high-strength recycled concrete as described above,
the reinforcing agent comprises triethanolamine, propylene carbonate, gypsum and slag,
the dosage ratio of the triethanolamine, the propylene carbonate, the gypsum and the slag is 1: 5: 3: 2.
the preparation method of the high-strength recycled concrete comprises the following steps:
(1) pretreatment: preparing cement, waste steel bars, fused magnesia, recycled aggregate, a reinforcing agent and a carboxylic acid high-efficiency water reducing agent, and conveying the mixture to a shade drying place for storage;
(2) cutting and crushing: selecting waste steel bars and fused magnesia, cutting the waste steel bars, and crushing the fused magnesia;
(3) mixing for the first time: selecting cement, recycled aggregate, a carboxylic acid high-efficiency water reducing agent and water to carry out primary mixing treatment;
(4) and (3) mixing for the second time: selecting waste steel bars, fused magnesia and a reinforcing agent for second mixing;
(5) and (3) finished product: and after the second mixing, spraying water for curing, and reducing the temperature to room temperature.
In the above-mentioned method for producing high-strength recycled concrete,
the length range of the waste steel bars cut in the step (2) is 1 cm;
the granularity range of the fused magnesia after being crushed in the step (2) is 0.5 mm.
In the above-mentioned method for producing high-strength recycled concrete,
the temperature of the first mixing in the step (3) is 60 ℃, the time of the first mixing is 2 hours, and the stirring speed of the first mixing is 300 r/min.
In the above-mentioned method for producing high-strength recycled concrete,
and (4) the temperature of the second mixing in the step (4) is 50 ℃, the time of the second mixing is 6 hours, and the stirring speed of the second mixing is 500 r/min.
Example 4
The high-strength recycled concrete comprises the following raw materials in parts by weight:
in the high-strength recycled concrete as described above,
the cement is common Portland cement 42.5;
the waste steel bars are subjected to rust removing treatment in advance;
the particle size range of the fused magnesia is 8 mm.
In the high-strength recycled concrete as described above,
the preparation method of the recycled aggregate comprises the following steps:
selecting sand river crushed stone, crushing to 8mm, then soaking in a polyvinyl alcohol solution with the mass concentration of 10%, and airing.
In the high-strength recycled concrete as described above,
the reinforcing agent comprises triethanolamine, propylene carbonate, gypsum and slag,
the dosage ratio of the triethanolamine, the propylene carbonate, the gypsum and the slag is 1: 5: 3: 2.
the preparation method of the high-strength recycled concrete comprises the following steps:
(1) pretreatment: preparing cement, waste steel bars, fused magnesia, recycled aggregate, a reinforcing agent and a carboxylic acid high-efficiency water reducing agent, and conveying the mixture to a shade drying place for storage;
(2) cutting and crushing: selecting waste steel bars and fused magnesia, cutting the waste steel bars, and crushing the fused magnesia;
(3) mixing for the first time: selecting cement, recycled aggregate, a carboxylic acid high-efficiency water reducing agent and water to carry out primary mixing treatment;
(4) and (3) mixing for the second time: selecting waste steel bars, fused magnesia and a reinforcing agent for second mixing;
(5) and (3) finished product: and after the second mixing, spraying water for curing, and reducing the temperature to room temperature.
In the above-mentioned method for producing high-strength recycled concrete,
the length range of the waste steel bars cut in the step (2) is 2 cm;
the granularity range of the fused magnesia after being crushed in the step (2) is 0.6 mm.
In the above-mentioned method for producing high-strength recycled concrete,
the temperature of the first mixing in the step (3) is 80 ℃, the time of the first mixing is 2 hours, and the stirring speed of the first mixing is 300 r/min.
In the above-mentioned method for producing high-strength recycled concrete,
in the step (4), the temperature of the second mixing is 60 ℃, the time of the second mixing is 6 hours, and the stirring speed of the second mixing is 500 r/min.
Example 5
The high-strength recycled concrete comprises the following raw materials in parts by weight:
in the high-strength recycled concrete as described above,
the cement is common Portland cement 42.5;
the waste steel bars are subjected to rust removing treatment in advance;
the particle size range of the fused magnesia is 6 mm.
In the high-strength recycled concrete as described above,
the preparation method of the recycled aggregate comprises the following steps:
selecting sand river crushed stone, crushing to 6mm, then soaking in a polyvinyl alcohol solution with the mass concentration of 10%, and airing.
In the high-strength recycled concrete as described above,
the reinforcing agent comprises triethanolamine, propylene carbonate, gypsum and slag,
the dosage ratio of the triethanolamine, the propylene carbonate, the gypsum and the slag is 1: 5: 3: 2.
the preparation method of the high-strength recycled concrete comprises the following steps:
(1) pretreatment: preparing cement, waste steel bars, fused magnesia, recycled aggregate, a reinforcing agent and a carboxylic acid high-efficiency water reducing agent, and conveying the mixture to a shade drying place for storage;
(2) cutting and crushing: selecting waste steel bars and fused magnesia, cutting the waste steel bars, and crushing the fused magnesia;
(3) mixing for the first time: selecting cement, recycled aggregate, a carboxylic acid high-efficiency water reducing agent and water to carry out primary mixing treatment;
(4) and (3) mixing for the second time: selecting waste steel bars, fused magnesia and a reinforcing agent for second mixing;
(5) and (3) finished product: and after the second mixing, spraying water for curing, and reducing the temperature to room temperature.
In the above-mentioned method for producing high-strength recycled concrete,
the length range of the waste steel bars cut in the step (2) is 1 cm;
the granularity range of the fused magnesia after being crushed in the step (2) is 0.5 mm.
In the above-mentioned method for producing high-strength recycled concrete,
the temperature of the first mixing in the step (3) is 70 ℃, the time of the first mixing is 2 hours, and the stirring speed of the first mixing is 300 r/min.
In the above-mentioned method for producing high-strength recycled concrete,
and (4) the temperature of the second mixing in the step (4) is 55 ℃, the time of the second mixing is 6 hours, and the stirring speed of the second mixing is 500 r/min.
Comparative example 1
The high-strength recycled concrete comprises the following raw materials in parts by weight:
in the high-strength recycled concrete as described above,
the cement is common Portland cement 42.5;
and the waste steel bars are subjected to rust removing treatment in advance.
In the high-strength recycled concrete as described above,
the preparation method of the recycled aggregate comprises the following steps:
selecting sand river crushed stone, crushing to 6mm, then soaking in a polyvinyl alcohol solution with the mass concentration of 10%, and airing.
In the high-strength recycled concrete as described above,
the reinforcing agent comprises triethanolamine, propylene carbonate, gypsum and slag,
the dosage ratio of the triethanolamine, the propylene carbonate, the gypsum and the slag is 1: 5: 3: 2.
the preparation method of the high-strength recycled concrete comprises the following steps:
(1) pretreatment: preparing cement, waste steel bars, fused magnesia, recycled aggregate, a reinforcing agent and a carboxylic acid high-efficiency water reducing agent, and conveying the mixture to a shade drying place for storage;
(2) cutting and crushing: selecting waste steel bars and fused magnesia, cutting the waste steel bars, and crushing the fused magnesia;
(3) mixing for the first time: selecting cement, recycled aggregate, a carboxylic acid high-efficiency water reducing agent and water to carry out primary mixing treatment;
(4) and (3) mixing for the second time: selecting waste steel bars and reinforcing agents to carry out second mixing;
(5) and (3) finished product: and after the second mixing, spraying water for curing, and reducing the temperature to room temperature.
In the above-mentioned method for producing high-strength recycled concrete,
the length range of the waste steel bars cut in the step (2) is 1 cm.
In the above-mentioned method for producing high-strength recycled concrete,
the temperature of the first mixing in the step (3) is 70 ℃, the time of the first mixing is 2 hours, and the stirring speed of the first mixing is 300 r/min.
In the above-mentioned method for producing high-strength recycled concrete,
and (4) the temperature of the second mixing in the step (4) is 55 ℃, the time of the second mixing is 6 hours, and the stirring speed of the second mixing is 500 r/min.
Comparative example 2
The high-strength recycled concrete comprises the following raw materials in parts by weight:
in the high-strength recycled concrete as described above,
the cement is common Portland cement 42.5;
the waste steel bars are subjected to rust removing treatment in advance;
the particle size range of the fused magnesia is 6 mm.
In the high-strength recycled concrete as described above,
the reinforcing agent comprises triethanolamine, propylene carbonate, gypsum and slag,
the dosage ratio of the triethanolamine, the propylene carbonate, the gypsum and the slag is 1: 5: 3: 2.
the preparation method of the high-strength recycled concrete comprises the following steps:
(1) pretreatment: preparing cement, waste steel bars, fused magnesia, recycled aggregate, a reinforcing agent and a carboxylic acid high-efficiency water reducing agent, and conveying the mixture to a shade drying place for storage;
(2) cutting and crushing: selecting waste steel bars and fused magnesia, cutting the waste steel bars, and crushing the fused magnesia;
(3) mixing for the first time: selecting cement, a carboxylic acid high-efficiency water reducing agent and water to carry out primary mixing treatment;
(4) and (3) mixing for the second time: selecting waste steel bars, fused magnesia and a reinforcing agent for second mixing;
(5) and (3) finished product: and after the second mixing, spraying water for curing, and reducing the temperature to room temperature.
In the above-mentioned method for producing high-strength recycled concrete,
the length range of the waste steel bars cut in the step (2) is 1 cm;
the granularity range of the fused magnesia after being crushed in the step (2) is 0.5 mm.
In the above-mentioned method for producing high-strength recycled concrete,
the temperature of the first mixing in the step (3) is 70 ℃, the time of the first mixing is 2 hours, and the stirring speed of the first mixing is 300 r/min.
In the above-mentioned method for producing high-strength recycled concrete,
and (4) the temperature of the second mixing in the step (4) is 55 ℃, the time of the second mixing is 6 hours, and the stirring speed of the second mixing is 500 r/min.
Comparative example 3
The high-strength recycled concrete comprises the following raw materials in parts by weight:
in the high-strength recycled concrete as described above,
the cement is common Portland cement 42.5;
the waste steel bars are subjected to rust removing treatment in advance;
the particle size range of the fused magnesia is 6 mm.
In the high-strength recycled concrete as described above,
the preparation method of the recycled aggregate comprises the following steps:
selecting sand river crushed stone, crushing to 6mm, then soaking in a polyvinyl alcohol solution with the mass concentration of 10%, and airing.
The preparation method of the high-strength recycled concrete comprises the following steps:
(1) pretreatment: preparing cement, waste steel bars, fused magnesia, recycled aggregate, a reinforcing agent and a carboxylic acid high-efficiency water reducing agent, and conveying the mixture to a shade drying place for storage;
(2) cutting and crushing: selecting waste steel bars and fused magnesia, cutting the waste steel bars, and crushing the fused magnesia;
(3) mixing for the first time: selecting cement, recycled aggregate, a carboxylic acid high-efficiency water reducing agent and water to carry out primary mixing treatment;
(4) and (3) mixing for the second time: selecting waste steel bars and fused magnesia for second mixing;
(5) and (3) finished product: and after the second mixing, spraying water for curing, and reducing the temperature to room temperature.
In the above-mentioned method for producing high-strength recycled concrete,
the length range of the waste steel bars cut in the step (2) is 1 cm;
the granularity range of the fused magnesia after being crushed in the step (2) is 0.5 mm.
In the above-mentioned method for producing high-strength recycled concrete,
the temperature of the first mixing in the step (3) is 70 ℃, the time of the first mixing is 2 hours, and the stirring speed of the first mixing is 300 r/min.
In the above-mentioned method for producing high-strength recycled concrete,
and (4) the temperature of the second mixing in the step (4) is 55 ℃, the time of the second mixing is 6 hours, and the stirring speed of the second mixing is 500 r/min.
Comparative example 4
The high-strength recycled concrete comprises the following raw materials in parts by weight:
in the high-strength recycled concrete as described above,
the cement is common Portland cement 42.5;
the waste steel bars are subjected to rust removing treatment in advance;
the particle size range of the fused magnesia is 6 mm.
In the high-strength recycled concrete as described above,
the preparation method of the recycled aggregate comprises the following steps:
selecting sand river crushed stone, crushing to 6mm, then soaking in a polyvinyl alcohol solution with the mass concentration of 10%, and airing.
In the high-strength recycled concrete as described above,
the reinforcing agent comprises triethanolamine and slag,
the dosage ratio of the triethanolamine to the slag is 1: 2.
the preparation method of the high-strength recycled concrete comprises the following steps:
(1) pretreatment: preparing cement, waste steel bars, fused magnesia, recycled aggregate, a reinforcing agent and a carboxylic acid high-efficiency water reducing agent, and conveying the mixture to a shade drying place for storage;
(2) cutting and crushing: selecting waste steel bars and fused magnesia, cutting the waste steel bars, and crushing the fused magnesia;
(3) mixing for the first time: selecting cement, recycled aggregate, a carboxylic acid high-efficiency water reducing agent and water to carry out primary mixing treatment;
(4) and (3) mixing for the second time: selecting waste steel bars, fused magnesia and a reinforcing agent for second mixing;
(5) and (3) finished product: and after the second mixing, spraying water for curing, and reducing the temperature to room temperature.
In the above-mentioned method for producing high-strength recycled concrete,
the length range of the waste steel bars cut in the step (2) is 1 cm;
the granularity range of the fused magnesia after being crushed in the step (2) is 0.5 mm.
In the above-mentioned method for producing high-strength recycled concrete,
the temperature of the first mixing in the step (3) is 70 ℃, the time of the first mixing is 2 hours, and the stirring speed of the first mixing is 300 r/min.
In the above-mentioned method for producing high-strength recycled concrete,
and (4) the temperature of the second mixing in the step (4) is 55 ℃, the time of the second mixing is 6 hours, and the stirring speed of the second mixing is 500 r/min.
Comparative example 5
The high-strength recycled concrete comprises the following raw materials in parts by weight:
in the high-strength recycled concrete as described above,
the cement is common Portland cement 42.5;
the waste steel bars are subjected to rust removing treatment in advance;
the particle size range of the fused magnesia is 6 mm.
In the high-strength recycled concrete as described above,
the preparation method of the recycled aggregate comprises the following steps:
selecting sand river crushed stone, crushing to 6mm, then soaking in a polyvinyl alcohol solution with the mass concentration of 10%, and airing.
In the high-strength recycled concrete as described above,
the reinforcing agent comprises propylene carbonate and gypsum,
the dosage ratio of the propylene carbonate to the gypsum is 5: 3.
the preparation method of the high-strength recycled concrete comprises the following steps:
(1) pretreatment: preparing cement, waste steel bars, fused magnesia, recycled aggregate, a reinforcing agent and a carboxylic acid high-efficiency water reducing agent, and conveying the mixture to a shade drying place for storage;
(2) cutting and crushing: selecting waste steel bars and fused magnesia, cutting the waste steel bars, and crushing the fused magnesia;
(3) mixing for the first time: selecting cement, recycled aggregate, a carboxylic acid high-efficiency water reducing agent and water to carry out primary mixing treatment;
(4) and (3) mixing for the second time: selecting waste steel bars, fused magnesia and a reinforcing agent for second mixing;
(5) and (3) finished product: and after the second mixing, spraying water for curing, and reducing the temperature to room temperature.
In the above-mentioned method for producing high-strength recycled concrete,
the length range of the waste steel bars cut in the step (2) is 1 cm;
the granularity range of the fused magnesia after being crushed in the step (2) is 0.5 mm.
In the above-mentioned method for producing high-strength recycled concrete,
the temperature of the first mixing in the step (3) is 70 ℃, the time of the first mixing is 2 hours, and the stirring speed of the first mixing is 300 r/min.
In the above-mentioned method for producing high-strength recycled concrete,
and (4) the temperature of the second mixing in the step (4) is 55 ℃, the time of the second mixing is 6 hours, and the stirring speed of the second mixing is 500 r/min.
Comparative example 6
The high-strength recycled concrete comprises the following raw materials in parts by weight:
in the high-strength recycled concrete as described above,
the cement is common Portland cement 42.5;
the waste steel bars are subjected to rust removing treatment in advance;
the particle size range of the fused magnesia is 6 mm.
In the high-strength recycled concrete as described above,
the preparation method of the recycled aggregate comprises the following steps:
selecting sand river crushed stone, crushing to 6mm, then soaking in a polyvinyl alcohol solution with the mass concentration of 10%, and airing.
In the high-strength recycled concrete as described above,
the reinforcing agent comprises triethanolamine, propylene carbonate, gypsum and slag,
the dosage ratio of the triethanolamine, the propylene carbonate, the gypsum and the slag is 1: 5: 3: 2.
the preparation method of the high-strength recycled concrete comprises the following steps:
(1) pretreatment: preparing cement, waste steel bars, fused magnesia, recycled aggregate, a reinforcing agent and a carboxylic acid high-efficiency water reducing agent, and conveying the mixture to a shade drying place for storage;
(2) cutting and crushing: selecting waste steel bars and fused magnesia, cutting the waste steel bars, and crushing the fused magnesia;
(3) mixing: selecting cement, recycled aggregate, a carboxylic acid high-efficiency water reducing agent, waste steel bars, fused magnesia, a reinforcing agent and water for mixing treatment;
(4) and (3) finished product: and after mixing, spraying water for curing, and reducing the temperature to room temperature.
In the above-mentioned method for producing high-strength recycled concrete,
the length range of the waste steel bars cut in the step (2) is 1 cm;
the granularity range of the fused magnesia after being crushed in the step (2) is 0.5 mm.
In the above-mentioned method for producing high-strength recycled concrete,
the mixing temperature in the step (3) is 70 ℃, the mixing time is 2 hours, and the mixing stirring speed is 300 r/min.
Test protocol
The concrete prepared in examples 1 to 5 and the concrete prepared in comparative examples 1 to 6 were selected and tested with reference to the following prior art:
(1) shoujianzhuang, langyang, shear performance test study of recycled concrete beams [ J ]. structural engineers, 2004,20(6):54-58,53.
(2) Zhang jin xi, Zhang Jianhua, Wu Changsen. research on the properties and pore structure of recycled concrete [ J ] academic report on building materials, 2006,9(002): 142-.
(3) Zhang Xinyue, Fangguangxu, Gihongbin, et al.
The relevant tests are shown in table 1:
TABLE 1
As can be seen from Table 1, compared with comparative examples 1 to 5, the concrete prepared in examples 1 to 5 of the present invention is superior in each property, and the apparent porosity, the flexural strength, the compressive strength, the linear change rate and other parameters are significantly different. On the basis of the existing recycled concrete, the invention adds the fused magnesia, the improved recycled aggregate and the brand-new reinforcing agent, simultaneously sets two mixing modes, realizes the synergistic interaction among all parameter conditions, endows the concrete with new excellent performance, not only changes the internal organization structure of the concrete, improves the constructability, but also greatly improves the strength of the concrete.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and substitutions can be made without departing from the technical principle of the present invention, and these modifications and substitutions should also be regarded as the protection scope of the present invention.
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