Recycled aggregate reinforced slurry and preparation method thereof
阅读说明：本技术 一种再生骨料强化浆液及其制备方法 (Recycled aggregate reinforced slurry and preparation method thereof ) 是由 赵华 胡勇 关博文 冯玉荣 薛兴杰 张硕文 王爱鹏 田乾 马子宸 邸文锦 于 2021-10-12 设计创作，主要内容包括：本发明属于建筑材料技术领域,公开了一种利用再生骨料强化浆液及其制备方法,包括下述质量百分比的组分：轻烧镁粉5～12%；六水合氯化镁4～16%；高吸水性聚合物1～4%；缓凝组分0.5～1%。并且本发明还进一步公开了所述再生骨料的制备方法。采用本发明技术方案,可以充分再利用氯氧镁水泥的性能特点,在短时间内制备出性能优异的颗粒状再生骨料,同时本发明不再生混凝土附着砂浆的水灰比和组成的影响,可以用于各种标号再生混凝土制备再生骨料。采用本发明制备的再生骨料压碎值、表观密度、吸水率和坚固性满足GB/T25177《混凝土用再生粗骨料》I类要求,最大化地利用再生混凝土,节约资源,保护环境。(The invention belongs to the technical field of building materials, and discloses a recycled aggregate reinforced slurry and a preparation method thereof, wherein the recycled aggregate reinforced slurry comprises the following components in percentage by mass: 5-12% of light-burned magnesium powder; 4-16% of magnesium chloride hexahydrate; 1-4% of a super absorbent polymer; 0.5-1% of retarding component. The invention further discloses a preparation method of the recycled aggregate. By adopting the technical scheme of the invention, the performance characteristics of the magnesium oxychloride cement can be fully reused, the granular recycled aggregate with excellent performance can be prepared in a short time, and meanwhile, the invention does not have the influence of the water-cement ratio and the composition of the mortar adhered to the recycled concrete, and can be used for preparing recycled aggregates from recycled concrete of various grades. The crushing value, apparent density, water absorption and firmness of the recycled aggregate prepared by the method meet the I-type requirements of GB/T25177 recycled coarse aggregate for concrete, the recycled concrete is utilized to the maximum extent, resources are saved, and the environment is protected.)
1. The recycled aggregate reinforced slurry is characterized by comprising the following components in percentage by mass: 5-12% of light-burned magnesium powder; 4-16% of magnesium chloride hexahydrate; 1-4% of a super absorbent polymer; 0.5-1% of a retarding component, wherein the super absorbent polymer is polyacrylamide absorbent resin.
2. The recycled aggregate-strengthening slurry of claim 1, wherein the light-burned magnesium powder contains 80% of magnesium oxide and 60% of active magnesium oxide.
3. The recycled aggregate strengthening slurry of claim 1, wherein the magnesium oxychloride content of the magnesium chloride hexahydrate is greater than 45%.
4. The recycled aggregate fortifying slurry of claim 1, wherein said set retarding component is a maltodextrin.
5. The recycled aggregate-strengthening slurry as claimed in claim 1, wherein the mass ratio of the magnesium oxide and the magnesium chloride in the light-burned magnesium powder and the magnesium chloride hexahydrate is n (MgO) to n (MgCl)2) Is 2:1 to 4: 1.
6. The preparation method of the recycled aggregate reinforced slurry is characterized by comprising the following steps of:
the method comprises the following steps: weighing light-burned magnesium powder, magnesium chloride hexahydrate, polyacrylamide resin and malt extract in sequence according to parts by weight;
step two: dissolving magnesium chloride hexahydrate in water to prepare a magnesium chloride solution, wherein the concentration of the obtained solution is 18-23%;
step three: mixing and stirring light-burned magnesium powder and a magnesium chloride solution in a reaction kettle to obtain magnesium oxychloride cement slurry;
step four: and (3) simultaneously adding the polyacrylamide resin and the malt paste into the magnesium oxychloride cement slurry obtained in the third step, and mixing and stirring uniformly to obtain the recycled aggregate reinforced slurry.
7. The method for preparing recycled aggregate reinforced slurry according to claim 6, wherein in the third step, the mixing and stirring time in the reaction kettle is 2-4 minutes.
8. The method for preparing recycled aggregate reinforced slurry according to claim 6, wherein in the fourth step, the mixing and stirring speed is 1000-1500 r/min, and the stirring time is 20-30 min.
9. The method for preparing recycled aggregate reinforced slurry according to claim 6, further comprising the step of reinforcing recycled aggregate with magnesium oxychloride cement slurry, wherein the reinforcing step is as follows:
placing the recycled aggregate into a magnesium oxychloride cement slurry solution for soaking for 4-8 h;
after soaking, steaming the recycled aggregate for 5-7 hours in an environment with the temperature of 60-70 ℃ and the relative humidity of 90-100%, and then taking out and airing;
carrying out mechanical vibration treatment on the dried recycled aggregate for 1-2 h, and removing crushed slag on the surface of the recycled aggregate;
soaking the cleaned recycled aggregate into the magnesium oxychloride cement slurry again for 2-4 h;
and after the soaking is finished, fishing out the soaked recycled aggregate and naturally drying the recycled aggregate.
10. The method for preparing a recycled aggregate reinforced slurry according to claim 9, wherein in the step 1), the recycled aggregate is soaked in the magnesium oxychloride cement slurry, and the magnesium oxychloride cement slurry is used for completely immersing the recycled aggregate.
Technical Field
The invention belongs to the field of building materials, and particularly relates to a recycled aggregate strengthening liquid and a preparation method thereof.
Background
In recent years, the investment of China on road engineering is greatly increased, and the road industry is concerned by much attention. The roadbed engineering of the road engineering needs larger earth volume, which provides a chance for the comprehensive utilization of the construction waste. The construction waste can be used as earthwork to fill up the roadbed, but the construction waste contains complex components, especially has a certain content of organic matters, so that organic components in the construction waste and unfavorable components which are not suitable for road engineering are removed. In addition, the broken concrete coarse and fine aggregate can be combined with lime or cement to be made into calculus, and can be used as a semi-rigid or rigid base layer. Not only the construction waste is treated, but also the excavation of the earthwork is reduced. The adoption of the recycled coarse aggregate of the waste concrete can reduce the exploitation of natural gravels and realize the recycling of domestic and construction wastes.
At present, various recycled aggregate strengthening methods are in the future in the growing view of recycling recycled aggregates in China.
National patent (CN 110498629B) discloses application of an ECC material in recycled aggregate reinforcement, recycled reinforced aggregate, and a preparation method and application thereof. The reinforced material comprises the following components: 113-152 parts of cement; 38-52 parts of fly ash; 1.4-1.9 parts of PE fibers; 3.5-4.7 of a water reducing agent; 30-41 parts of water. The crushing index of the recycled aggregate reinforced by the ECC material is improved by 37.4%, and the compressive strength of concrete 7d prepared by using the reinforced recycled aggregate is higher than that of common recycled aggregate.
National patent (CN 108298849A) discloses a method for strengthening recycled aggregate by using dilute acetic acid solution. After the recycled aggregate is soaked in 0.6-1.8% dilute acetic acid for 12-168 hours, the water absorption, apparent density and crushing value of the recycled aggregate are improved to a certain degree, and the soaking liquid and the recycled slag can also be used as raw materials for preparing concrete.
National patent (CN 110668727A) discloses a cleaning and strengthening method of waste concrete recycled aggregate. The recycled concrete after being washed and crushed by ultrasonic waves is reinforced by a reinforcing material consisting of 20-40 parts of penetrating agent, 15-20 parts of silica fume, 5-10 parts of nano material and 1-2 parts of catalytic component. The method can effectively improve the cleaning efficiency, reduce the water absorption of the recycled aggregate and improve the strength of the aggregate, thereby improving the working performance of the recycled concrete.
The above patents provide some methods of recycled aggregate reinforcement, but still do not meet the engineering needs. The current recycled aggregate has the following disadvantages: 1. the recycled aggregate has high water absorption rate and high water absorption speed, and is influenced by the matrix concrete, so that the dispersion of the water absorption rate is large. Meanwhile, the water absorption rate of the recycled aggregate is far higher than that of the natural aggregate. 2. The crushing index of the recycled aggregate is higher than that of the natural aggregate, and the crushing index of the general recycled aggregate is 15-25 percent and is far higher than that of the natural aggregate. 3. The recycled aggregate is unstable in source, uneven in mass and large in randomness and variability, and the variability of the compressive strength of the recycled concrete is increased.
These characteristics greatly affect the mix ratio design and workability of recycled concrete. The reinforced recycled aggregate has an important effect on improving the strength of recycled concrete, and has very important practical significance on applying the recycled concrete to an environment with slightly high strength requirement.
Disclosure of Invention
The invention aims to provide a preparation method of recycled aggregate reinforced slurry, which solves the problems of high water absorption, high crushing value and poor quality of recycled aggregates in the background. In order to achieve the purpose, the invention is realized by adopting the following technical scheme.
The invention discloses a recycled aggregate reinforced slurry, which is prepared from the following components in percentage by weight: 5-12% of light-burned magnesium powder; 4-16% of magnesium chloride hexahydrate; 1-4% of a super absorbent polymer; 0.5-1% of retarding component.
Furthermore, the content of magnesium oxide in the light-burned magnesium powder is 80%, and the content of active magnesium oxide in the light-burned magnesium powder is 60%.
Further, the content of magnesium oxychloride in the magnesium chloride hexahydrate is more than 45%.
Further, the super absorbent polymer is a polyacrylamide water absorbent resin.
Further, the retarding component is maltodextrin.
Further, n (MgO) to n (MgCl) in the component2) Is 2:1 to 4: 1.
The invention discloses a recycled aggregate reinforced slurry and a preparation method thereof, and the method comprises the following steps:
the method comprises the following steps: weighing light-burned magnesium powder, magnesium chloride hexahydrate, polyacrylamide resin and malt extract in sequence according to parts by weight;
step two: dissolving magnesium chloride hexahydrate in water to prepare a magnesium chloride solution, wherein the concentration of the obtained solution is 18-23%;
step three: mixing and stirring light-burned magnesium powder and a magnesium chloride solution in a reaction kettle to obtain magnesium oxychloride cement slurry;
step four: and (3) simultaneously adding the polyacrylamide resin and the malt paste into the magnesium oxychloride cement slurry obtained in the third step, and mixing and stirring uniformly to obtain the recycled aggregate reinforced slurry.
Preferably, the stirring time in the third step is 2-4 minutes.
Preferably, in the fourth step, the mixing and stirring speed is 1000-1500 r/min, and the stirring time is 20-30 min.
In addition, the invention also discloses a process for strengthening the recycled aggregate, which comprises the following steps:
1) placing the recycled aggregate into a magnesium oxychloride cement slurry solution for soaking for 4-8 h;
2) after soaking, steaming the recycled aggregate for 5-7 hours at the temperature of 60-70 ℃ in an environment with relative humidity of 90-100%, and then taking out and airing;
3) carrying out mechanical vibration treatment on the dried recycled aggregate, and removing crushed slag on the surface of the recycled aggregate;
4) soaking the cleaned recycled aggregate into the magnesium oxychloride cement slurry again for 2-4 h;
5) and after the soaking is finished, fishing out the soaked recycled aggregate and naturally drying the recycled aggregate.
The recycled aggregate is recycled coarse aggregate obtained by crushing and grading recycled concrete, and the particle size range is 5-40 mm.
And in the step 1), the recycled aggregate is placed in magnesium oxychloride cement slurry for soaking, and the magnesium oxychloride cement slurry is required to completely immerse the recycled aggregate.
The vibration treatment time in the step 3) is 1-2 h.
The inventor finds out in the research process that: magnesium oxychloride cement prepared from light-burned magnesium powder and magnesium chloride solution as special component 3Mg (OH)2·MgCl2·8H2O (3. 1.8 phase) and 5Mg (OH)2·Mg(Cl)2·8H2The O (5, 1 and 8 phase) has better mechanical property, wear resistance and frost resistance, has the characteristics of good corrosion resistance, bonding property and the like, and is very suitable for reinforcing recycled aggregate to improve the mechanical property and reduce the crushing value. The high water-absorbing polymer is doped, so that the water resistance of the magnesium oxychloride cement can be improved, and the effect of reducing the water absorption of the recycled aggregate can be achieved. The malt paste can improve the fluidity of the magnesium oxychloride cement slurry and has better retardation.
The invention provides a recycled aggregate strengthening liquid and a preparation method thereof, and the recycled aggregate strengthening liquid has the following beneficial effects:
(1) the recycled aggregate reinforced slurry can be used for attaching a magnesium oxychloride cement coating on the surface of a recycled aggregate, and aims to solve the problems of rough surface, high porosity, high water absorption and high crushing index of the recycled aggregate, improve the physical properties of the recycled aggregate, ensure good mechanical properties of the recycled aggregate and improve the mechanical properties of prepared recycled concrete.
(2) The invention has the advantages of easy preparation, obvious effect, wide application range and the like, and can be used in the production process of the building waste recycled aggregate.
Detailed Description
The invention is further described in detail with reference to specific embodiments, which are intended to be understood more clearly from the theoretical design and practical aspects, and any modifications or changes that can be easily made by a person skilled in the art without departing from the technical solution of the invention fall within the scope of the claims of the present invention.
Examples
Example 1 recycled aggregate-reinforced slurry and method for preparing the same
The paint is prepared from the following components in percentage by weight: 6 percent of light-burned magnesium powder; 5% of magnesium chloride hexahydrate; 1% of a super absorbent polymer; 0.5 percent of retarding component.
The recycled aggregate is recycled coarse aggregate obtained by crushing and grading recycled concrete, and the particle size range is 5-25 mm.
The preparation method of the recycled aggregate strengthening method comprises the following steps:
(1) placing the recycled aggregate in a magnesium oxychloride cement slurry solution for soaking for 4 hours;
(2) after soaking, steaming the recycled aggregate for 5 hours at 60 ℃ in an environment with 90% relative humidity, and then taking out and airing;
(3) carrying out mechanical vibration treatment on the dried recycled aggregate, and removing crushed slag on the surface of the recycled aggregate;
(4) soaking the cleaned recycled aggregate into the magnesium oxychloride cement slurry again for 2 hours;
(5) after soaking, fishing out the soaked recycled aggregate and naturally drying the recycled aggregate;
example 2 recycled aggregate-reinforced slurry and method for preparing the same
The paint is prepared from the following components in percentage by weight: 8% of light-burned magnesium powder; 6% of magnesium chloride hexahydrate; 1.5% of high water absorption polymer; 0.7 percent of retarding component.
The recycled aggregate is recycled coarse aggregate obtained by crushing and grading recycled concrete, and the particle size range is 10-30 mm.
The preparation method of the recycled aggregate strengthening method comprises the following steps:
(1) placing the recycled aggregate in a magnesium oxychloride cement slurry solution for soaking for 6 hours;
(2) after soaking, steaming the recycled aggregate for 6 hours at 60 ℃ in an environment with 90% relative humidity, and then taking out and airing;
(3) carrying out mechanical vibration treatment on the dried recycled aggregate, and removing crushed slag on the surface of the recycled aggregate;
(4) soaking the cleaned recycled aggregate into the magnesium oxychloride cement slurry again for 3 hours;
(5) after soaking, fishing out the soaked recycled aggregate and naturally drying the recycled aggregate;
example 3 recycled aggregate-reinforced slurry and method of making the same
The paint is prepared from the following components in percentage by weight: 6 percent of light-burned magnesium powder; 12% of magnesium chloride hexahydrate; 2% of a super absorbent polymer; 9 percent of retarding component.
The recycled aggregate is recycled coarse aggregate obtained by crushing and grading recycled concrete, and the particle size range is 10-40 mm.
The preparation method of the recycled aggregate strengthening method comprises the following steps:
(1) placing the recycled aggregate in a magnesium oxychloride cement slurry solution for soaking for 8 hours;
(2) after soaking, steaming the recycled aggregate for 7 hours at 70 ℃ in an environment with 90% relative humidity, and then taking out and airing;
(3) carrying out mechanical vibration treatment on the dried recycled aggregate, and removing crushed slag on the surface of the recycled aggregate;
(4) soaking the cleaned recycled aggregate into the magnesium oxychloride cement slurry again for 4 hours;
(5) after soaking, fishing out the soaked recycled aggregate and naturally drying the recycled aggregate;
comparative examples 1 to 3 recycled concrete from the same source as in examples 1 to 3 was used and crushed into recycled crushed stone having the same particle size by a jaw crusher.
To illustrate the properties of the recycled aggregate of the present invention, the inventors conducted the following performance tests:
the recycled aggregates prepared in examples 1 to 3 of the present invention and the recycled aggregates prepared in comparative examples 1 to 3 were measured for the crushing value, apparent density, water absorption and firmness according to "pebbles and rubbles for construction" GB/T14685), and the results of the measurements are shown in table 1.
TABLE 1 results of measurements of crushing value, apparent density, water absorption and soundness
Type of curing agent
Crush value/%)
Apparent density/kg/m3
Water absorption/%)
Firmness%
Example 1
5.1
2601
1.2
3.1
Example 2
4.2
2573
1.7
2.1
Example 3
4.5
2563
0.9
2.3
Comparative example 1
25.3
2156
8.9
22.4
Comparative example 2
18.7
2246
6.2
18.7
Comparative example 3
13.6
2315
5.6
15.3
Recycled aggregate of I type
＜12.0
＞2450
＜3.0
＜5.0
As can be seen from Table 1, compared with the prior art, the technical scheme of the invention can fully strengthen the recycled aggregate in a short time and obtain excellent effects by fully utilizing the advantages of the magnesium oxychloride cement. The prepared recycled aggregate meets the I-type requirements of GB/T25177 recycled coarse aggregate for concrete, can maximally utilize recycled concrete, saves resources and protects the environment.
It is to be understood that the foregoing is only illustrative of the preferred embodiments of the present invention and that no limitation to the scope of the invention is thereby intended, such alterations and modifications being within the spirit and scope of the invention.
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