CN110937836B - Method for reinforcing quality of recycled coarse aggregate by adopting strong acid three stages - Google Patents
Method for reinforcing quality of recycled coarse aggregate by adopting strong acid three stages Download PDFInfo
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- CN110937836B CN110937836B CN201911107299.XA CN201911107299A CN110937836B CN 110937836 B CN110937836 B CN 110937836B CN 201911107299 A CN201911107299 A CN 201911107299A CN 110937836 B CN110937836 B CN 110937836B
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
- C04B20/02—Treatment
- C04B20/023—Chemical treatment
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
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Abstract
The invention discloses a method for reinforcing the quality of recycled coarse aggregate by adopting three stages of strong acid, which comprises the following steps: firstly, placing the regenerated coarse aggregate in a hydrochloric acid solution and soaking for a period of time; secondly, adding a nitric acid solution into the hydrochloric acid solution after soaking for a period of time, and taking out the regenerated coarse aggregate after soaking for a period of time; then, putting the taken out coarse aggregate into clear water for multiple times of cleaning until the clear water is neutral, and taking out the coarse aggregate; then, putting the taken out regenerated coarse aggregate into a sulfuric acid solution, and taking out the regenerated coarse aggregate after soaking for a period of time; and finally, putting the taken out recycled coarse aggregate into clear water for multiple times of cleaning until the clear water is neutral, and taking out the recycled coarse aggregate to obtain the reinforced recycled coarse aggregate. The method comprises the steps of soaking the regenerated coarse aggregate in a strong acid solution, corroding mortar attached to the surface layer and inside the coarse aggregate, and reacting sulfuric acid with residual calcium ions to form a compact layer so as to improve the apparent density and water absorption of the coarse aggregate, strengthen the service performance of the regenerated aggregate and achieve the standard of engineering application specifications.
Description
Technical Field
The invention belongs to the technical field of performance enhancement of recycled building wastes, and relates to a method for enhancing the quality of recycled coarse aggregates by adopting a strong acid three-stage method.
Background
In the rapid development of the construction industry, the demand for natural sandstone aggregate is increasing day by day, and the production of the natural sandstone aggregate needs to excavate a large amount of mountains, so that the environment can not be damaged greatly, and the natural sandstone resource is nearly exhausted at present. In addition, in the urbanization construction of China, natural disasters such as earthquakes and landslides and removal projects generate a large amount of construction waste, the types of the construction waste are various, 41 percent of the construction waste is waste concrete, and the proportion of the construction waste is very large. The construction waste piled in the open air is visible everywhere, which not only wastes the land space, but also causes serious damage to the water body and the air, influences the appearance and appearance of the city, and is very unfavorable for the development of the city. At present, waste concrete is generally crushed, screened and the like, and then is partially or completely substituted for concrete prepared by natural aggregate, namely recycled concrete. The application of the recycled concrete not only slows down the exploitation and use of natural aggregate and greatly improves the problem of gradual exhaustion of natural resources, but also ensures that the concrete construction industry does not excessively depend on natural sandstone resources. The development of recycled concrete converts construction waste into usable construction materials, and reduces the damage to the environment. The recycled concrete realizes the harmonious development of the building industry and the nature, and plays an important role in the sustainable development of the concrete industry.
The adoption of the recycled coarse aggregate of the waste concrete can realize the recycling of domestic and construction wastes. Since a large amount of used mortar adheres to the surface of the recycled coarse aggregate, the porosity is high and the water absorption is high, thereby reducing the strength of concrete. At present, domestic researchers mostly adopt additional materials with different properties (such as fly ash, silica fume, cement, mortar, nano materials and the like) to carry out treatments such as dipping, leaching, drying and the like on the recycled aggregate, the method utilizes the characteristic that the additional materials have cohesiveness to coat the outer surface of the recycled concrete, however, the method only reflects the reinforcement of the recycled aggregate on the surface, the influence on the internal structure is small, and the purchase cost of most of the additives is high.
Disclosure of Invention
The invention aims to provide a method for reinforcing the quality of recycled coarse aggregate by adopting three stages of strong acid, and the purpose of reinforcing the service performance of the recycled aggregate is realized.
The technical scheme adopted by the invention is that a method for reinforcing the quality of recycled coarse aggregate by adopting three stages of strong acid is implemented according to the following steps:
step 1, placing the recycled coarse aggregate in a hydrochloric acid solution and soaking for a period of time;
step 2, adding a nitric acid solution into the hydrochloric acid solution soaked in the step 1 for a period of time, and taking out the regenerated coarse aggregate after soaking for a period of time;
step 3, putting the recycled coarse aggregate taken out in the step 2 into clear water for multiple times of cleaning, and taking out the recycled coarse aggregate until the clear water is neutral;
step 4, putting the recycled coarse aggregate taken out in the step 3 into a sulfuric acid solution, and taking out the recycled coarse aggregate after soaking for a period of time;
and 5, putting the recycled coarse aggregate taken out in the step 4 into clear water for multiple times of cleaning, and taking out the recycled coarse aggregate until the clear water is neutral, thereby obtaining the reinforced recycled coarse aggregate.
The present invention is also characterized in that,
the soaking period in the step 1, the step 2 and the step 4 is specifically 1 to 5 days.
The recycled coarse aggregate comprises waste concrete, and the particle grade of the recycled coarse aggregate is 5-30 mm.
The concentration of the hydrochloric acid solution, the concentration of the nitric acid solution and the concentration of the sulfuric acid solution are all 0.05 mol/L-0.20 mol/L.
In the soaking processes of the step 1, the step 2 and the step 4, the acid solution is required to completely immerse the recycled coarse aggregate.
In the soaking process in the step 1 and the step 2, the pH value range of the soaking solution is kept between 0.7 and 1.3.
And 4, in the soaking process in the step 4, the pH value range of the soaking solution is kept between 0.4 and 1.0.
And (3) testing the pH value of the soaking solution once every two hours, and if the pH value is not in the target range, adding a sulfuric acid solution to adjust the pH value of the soaking solution to the target range.
The concentration of the hydrochloric acid solution added in the step 1 is 0.05 mol/L-0.20 mol/L; the concentration of the nitric acid solution added in the step 2 is 0.05 mol/L-0.20 mol/L;
the concentration of the sulfuric acid solution added in the step 4 is 0.05 mol/L-0.20 mol/L.
The method for reinforcing the quality of the recycled coarse aggregate by adopting the three stages of strong acid has at least the following beneficial effects:
firstly, the recycled coarse aggregate of the waste concrete is repaired in multiple stages by using a strong acid solution, the apparent density of the recycled coarse aggregate is improved, the water absorption is reduced, the water absorption and the apparent density reach the II-stage standard of the recycled coarse aggregate for the national standard GB/T25177-2010 concrete, and the recycled coarse aggregate can be used for preparing new concrete, so that the problem of disposal of construction waste can be solved, and a thought can be provided for recycling the construction waste with high quality.
And secondly, compared with the high-quality recycled aggregate prepared by other methods, the production cost is reduced, the recycled aggregate can be widely utilized, the problems of difficult treatment of a large amount of concrete wastes and negative influence on the environment caused by the difficult treatment of the concrete wastes are solved, a large amount of garbage treatment cost is saved, and huge social benefits and environmental protection benefits are generated.
Thirdly, the acid solution after the method is adopted can be recycled and continuously utilized, so that the cost of the reinforced recycled concrete aggregate is reduced; meanwhile, the coarse aggregate is reinforced by the additive in the traditional method, the cost of the additive is high, the reinforcing step of the invention uses strong acid, the cost is low, the method is easy to obtain, and the cost of the reinforced recycled coarse aggregate is greatly reduced on the whole from the two aspects of the cost of the material and the cost of the substituted material.
Fourthly, the performance of the reinforced recycled aggregate is greatly improved, so that the reinforced recycled aggregate can be used on large-volume concrete buildings with higher requirements on the durability of concrete, such as concrete gravity dams, concrete arch dams, concrete rock-fill dams and the like, and has certain improvement effect on the frost resistance, the sulfate erosion resistance and the carbonization resistance of the large-volume concrete buildings.
Detailed Description
The present invention will be described in detail with reference to specific examples.
The invention adopts a method for strengthening the performance of regenerated coarse aggregate by adopting strong acid, firstly, the mortar chips on the surface are treated by soaking the coarse aggregate in hydrochloric acid, but the mortar adhered on the surface can not be deeply treated and fall off because the corrosivity of the hydrochloric acid is slightly weak; then adding nitric acid into the soaking solution, and combining the nitric acid and the soaking solution to form 'aqua regia', which has strong oxidizing property and strong corrosivity, so as to remove the corrosion to the aggregate mortar; then, cleaning the mixed solution of hydrochloric acid and nitric acid, further cleaning the mortar of the recycled aggregate, and still leaving a small amount of mortar on the surface of the aggregate without cleaning; finally, the coarse aggregate is immersed in a sulfuric acid solution, calcium sulfate (gypsum) sediment is generated through the added sulfate radicals and a small amount of residual calcium ions in the mortar, the surface mortar is compacted, the performance of the recycled aggregate is enhanced, and the problem of low performance of the recycled coarse aggregate is solved.
The invention discloses a method for reinforcing the quality of recycled coarse aggregate by adopting three stages of strong acid, which is implemented according to the following steps:
step 1, placing the regenerated coarse aggregate into a hydrochloric acid solution with the concentration of 0.05-0.20 mol/L and soaking for 1-5 days, wherein the particle grade of the regenerated coarse aggregate is 5-30 mm; the pH value of the soaking solution is kept in the range of 0.7-1.3, the pH value of the soaking solution is tested every two hours, and if the pH value of the soaking solution is not in the target range of 0.7-1.3, hydrochloric acid solution with the concentration of 0.05-0.20 mol/L is added to adjust the pH value of the soaking solution to the target range;
step 2, adding nitric acid solution with the concentration of 0.05-0.20 mol/L into the hydrochloric acid solution soaked in the step 1 for a period of time, soaking for 1-5 days, and taking out the regenerated coarse aggregate; the pH value of the soaking solution is kept in the range of 0.7-1.3, the pH value of the soaking solution is tested every two hours, and if the pH value of the soaking solution is not in the target range of 0.7-1.3, nitric acid solution with the concentration of 0.05-0.20 mol/L is added to adjust the pH value of the soaking solution to the target range;
step 3, putting the recycled coarse aggregate taken out in the step 2 into clear water for multiple times of cleaning, and taking out the recycled coarse aggregate until the clear water is neutral;
step 4, putting the regenerated coarse aggregate taken out in the step 3 into a sulfuric acid solution with the concentration of 0.05-0.20 mol/L, soaking for 1-5 days, and taking out the regenerated coarse aggregate; the pH value of the soaking solution is kept in the range of 0.4-1.0, the pH value of the soaking solution is tested every two hours, and if the pH value of the soaking solution is not in the target range of 0.4-1.0, a sulfuric acid solution with the concentration of 0.05 mol/L-0.20 mol/L is added to adjust the pH value of the soaking solution to the target range;
and 5, putting the recycled coarse aggregate taken out in the step 4 into clear water for multiple times of cleaning, and taking out the recycled coarse aggregate until the clear water is neutral, thereby obtaining the reinforced recycled coarse aggregate.
Example 1
A method for reinforcing the quality of recycled coarse aggregate by adopting three stages of strong acid is implemented according to the following steps:
step 1, placing the recycled coarse aggregate into a hydrochloric acid solution with the concentration of 0.05mol/L and soaking for 1 day, wherein the particle grade of the recycled coarse aggregate is 5-30 mm; testing the pH value of the soaking solution once every two hours, and if the pH value of the soaking solution is not 1.3, adding a sulfuric acid solution with the concentration of 0.05mol/L to adjust the pH value of the soaking solution to be 1.3;
step 2, adding a nitric acid solution with the concentration of 0.05mol/L into the hydrochloric acid solution soaked in the step 1 for a period of time, soaking for 1 day, and taking out the regenerated coarse aggregate; testing the pH value of the soaking solution once every two hours, and if the pH value of the soaking solution is not 1.3, adding a sulfuric acid solution with the concentration of 0.05mol/L to adjust the pH value of the soaking solution to be 1.3;
step 3, putting the recycled coarse aggregate taken out in the step 2 into clear water for multiple times of cleaning, and taking out the recycled coarse aggregate until the clear water is neutral;
step 4, putting the regenerated coarse aggregate taken out in the step 3 into a sulfuric acid solution with the concentration of 0.05mol/L, and taking out the regenerated coarse aggregate after soaking for 1 day; testing the pH value of the soaking solution once every two hours, and if the pH value of the soaking solution is not 1.0, adding a sulfuric acid solution with the concentration of 0.05 mol/L-0.20 mol/L to adjust the pH value of the soaking solution to 1.0;
and 5, putting the recycled coarse aggregate taken out in the step 4 into clear water for multiple times of cleaning, and taking out the recycled coarse aggregate until the clear water is neutral, thereby obtaining the reinforced recycled coarse aggregate.
The soaking time of the solutions of the step 1, the step 2 and the step 4 in the embodiment 1 is implemented once according to 2 days, and other steps are not changed; the soaking time of the solutions of the step 1, the step 2 and the step 4 in the embodiment 1 is implemented once according to 3 days, and other steps are not changed; the soaking time of the solutions of the step 1, the step 2 and the step 4 in the embodiment 1 is implemented once according to 4 days, and other steps are not changed; the soaking time of the solutions of step 1, step 2 and step 4 in example 1 was performed once in 5 days, and the other steps were not changed.
Example 2
A method for reinforcing the quality of recycled coarse aggregate by adopting three stages of strong acid is implemented according to the following steps:
step 1, placing the recycled coarse aggregate into a hydrochloric acid solution with the concentration of 0.1mol/L and soaking for 1 day, wherein the particle grade of the recycled coarse aggregate is 5-30 mm; testing the pH value of the soaking solution once every two hours, and if the pH value of the soaking solution is not 1.0, adding a sulfuric acid solution with the concentration of 0.05 mol/L-0.20 mol/L to adjust the pH value of the soaking solution to 1.0;
step 2, adding nitric acid solution with the concentration of 0.05-0.20 mol/L into the hydrochloric acid solution soaked in the step 1 for a period of time, and taking out regenerated coarse aggregate after soaking for 1 day; testing the pH value of the soaking solution once every two hours, and if the pH value of the soaking solution is not 1.0, adding a sulfuric acid solution with the concentration of 0.1mol/L to adjust the pH value of the soaking solution to 1.0;
step 3, putting the recycled coarse aggregate taken out in the step 2 into clear water for multiple times of cleaning, and taking out the recycled coarse aggregate until the clear water is neutral;
step 4, putting the regenerated coarse aggregate taken out in the step 3 into a sulfuric acid solution with the concentration of 0.1mol/L, and taking out the regenerated coarse aggregate after soaking for 1 day; testing the pH value of the soaking solution once every two hours, and if the pH value of the soaking solution is not 0.7, adding a sulfuric acid solution with the concentration of 0.1mol/L to adjust the pH value of the soaking solution to be 0.7;
and 5, putting the recycled coarse aggregate taken out in the step 4 into clear water for multiple times of cleaning, and taking out the recycled coarse aggregate until the clear water is neutral, thereby obtaining the reinforced recycled coarse aggregate.
The soaking time of the solutions of the step 1, the step 2 and the step 4 in the embodiment 2 is implemented once according to 2 days, and other steps are unchanged; the soaking time of the solutions of step 1, step 2 and step 4 in the embodiment 2 is implemented once according to 3 days, and other steps are not changed; the soaking time of the solutions of the step 1, the step 2 and the step 4 in the embodiment 2 is implemented once according to 4 days, and other steps are not changed; the soaking time of the solutions of step 1, step 2 and step 4 in example 2 was performed once in 5 days, and the other steps were not changed.
Example 3
A method for reinforcing the quality of recycled coarse aggregate by adopting three stages of strong acid is implemented according to the following steps:
step 1, placing the recycled coarse aggregate into a hydrochloric acid solution with the concentration of 0.15mol/L and soaking for 1 to 5 days, wherein the particle grade of the recycled coarse aggregate is 5 to 30 mm; testing the pH value of the soaking solution once every two hours, and if the pH value of the soaking solution is not 0.83, adding a sulfuric acid solution with the concentration of 0.15mol/L to adjust the pH value of the soaking solution to be 0.83;
step 2, adding a nitric acid solution with the concentration of 0.15mol/L into the hydrochloric acid solution soaked in the step 1 for a period of time, soaking for 1 day, and taking out the regenerated coarse aggregate; testing the pH value of the soaking solution once every two hours, and if the pH value of the soaking solution is not 0.83, adding a sulfuric acid solution with the concentration of 0.15mol/L to adjust the pH value of the soaking solution to be 0.83;
step 3, putting the recycled coarse aggregate taken out in the step 2 into clear water for multiple times of cleaning, and taking out the recycled coarse aggregate until the clear water is neutral;
step 4, putting the regenerated coarse aggregate taken out in the step 3 into a sulfuric acid solution with the concentration of 0.15mol/L, and taking out the regenerated coarse aggregate after soaking for 1 day; testing the pH value of the soaking solution once every two hours, and if the pH value of the soaking solution is not 0.52, adding a sulfuric acid solution with the concentration of 0.15mol/L to adjust the pH value of the soaking solution to be not 0.52;
and 5, putting the recycled coarse aggregate taken out in the step 4 into clear water for multiple times of cleaning, and taking out the recycled coarse aggregate until the clear water is neutral, thereby obtaining the reinforced recycled coarse aggregate.
The soaking time of the solutions of the step 1, the step 2 and the step 4 in the embodiment 3 is implemented once according to 2 days, and other steps are not changed; the soaking time of the solutions of the step 1, the step 2 and the step 4 in the embodiment 3 is implemented once according to 3 days, and other steps are not changed; the soaking time of the solutions of the step 1, the step 2 and the step 4 in the embodiment 3 is implemented once according to 4 days, and other steps are not changed; the soaking time of the solutions of step 1, step 2 and step 4 in example 3 was performed once in 5 days, and the other steps were not changed.
Example 4
A method for reinforcing the quality of recycled coarse aggregate by adopting three stages of strong acid is implemented according to the following steps:
step 1, placing the recycled coarse aggregate into a hydrochloric acid solution with the concentration of 0.20mol/L and soaking for 1 day, wherein the particle grade of the recycled coarse aggregate is 5-30 mm; testing the pH value of the soaking solution once every two hours, and if the pH value of the soaking solution is not 0.7, adding a sulfuric acid solution with the concentration of 0.20mol/L to adjust the pH value of the soaking solution to be 0.7;
step 2, adding a nitric acid solution with the concentration of 0.20mol/L into the hydrochloric acid solution soaked in the step 1 for a period of time, soaking for 1 day, and taking out the regenerated coarse aggregate; testing the pH value of the soaking solution once every two hours, and if the pH value of the soaking solution is not 0.7, adding a sulfuric acid solution with the concentration of 0.20mol/L to adjust the pH value of the soaking solution to be 0.7;
step 3, putting the recycled coarse aggregate taken out in the step 2 into clear water for multiple times of cleaning, and taking out the recycled coarse aggregate until the clear water is neutral;
step 4, putting the regenerated coarse aggregate taken out in the step 3 into a sulfuric acid solution with the concentration of 0.20mol/L, and taking out the regenerated coarse aggregate after soaking for 1 day; testing the pH value of the soaking solution once every two hours, and if the pH value of the soaking solution is not 0.4, adding a sulfuric acid solution with the concentration of 0.05 mol/L-0.20 mol/L to adjust the pH value of the soaking solution to be 0.4;
and 5, putting the recycled coarse aggregate taken out in the step 4 into clear water for multiple times of cleaning, and taking out the recycled coarse aggregate until the clear water is neutral, thereby obtaining the reinforced recycled coarse aggregate.
The soaking time of the solutions of the step 1, the step 2 and the step 4 in the embodiment 4 is implemented once according to 2 days, and other steps are not changed; the soaking time of the solutions of the step 1, the step 2 and the step 4 in the embodiment 4 is implemented once according to 3 days, and other steps are not changed; the soaking time of the solutions of the step 1, the step 2 and the step 4 in the embodiment 4 is implemented once according to 4 days, and other steps are not changed; the soaking time of the solutions of step 1, step 2 and step 4 in example 4 was performed once every 5 days, and the other steps were not changed.
Comparative example 1
The recycled coarse aggregate with the particle size grade of 5 mm-30 mm is taken and is not treated.
Test data:
the apparent density and water absorption of the reinforced recycled coarse aggregates obtained in examples 1 to 4 were measured, and the obtained data are shown in tables 1 and 2 below; the apparent density and water absorption of the untreated recycled coarse aggregate of comparative example 1 were measured, and the obtained data are shown in tables 1 and 2 below:
TABLE 1 recycled aggregate Water absorption test results
Table 2 recycled aggregate apparent density test results
TABLE 3 recycled coarse aggregate classification
| Item | Class I | Class II | Class III |
| Water absorption (%) | ＜3.0 | ＜5.0 | ＜8.0 |
| Apparent density (g/cm)3) | ＞2.45 | ＞2.35 | ＞2.25 |
Apparent density and water absorption are important indexes for reflecting aggregate performance in building engineering application, and shown in tables 1 and 2, after the strong acid three-stage reinforced recycled aggregate is adopted in the invention, the water absorption is obviously reduced in different degrees, and the apparent density is obviously improved in different degrees, so that the service performance of the treated recycled aggregate is greatly improved. Considering the results of the water absorption and the apparent density of the recycled coarse aggregate together, the optimal situation appears in example 2, wherein the concentration of the acid solution is 0.10mol/L, the soaking time of each acid solution is 2 days, and the water absorption of the recycled aggregate is reduced by 47.5 percent and the apparent density is increased by 9.9 percent.
Experiments show that the concentration of the acid solution has an important influence on the water absorption rate and the apparent density of the recycled aggregate, and when the mass concentration of the acid solution is 0.1mol/L, the water absorption rate of the recycled aggregate can be effectively reduced, and the apparent density can be effectively increased. Through experimental research, the apparent density is slightly reduced although the water absorption of the recycled aggregate can be effectively reduced when the concentration of the acid solution is more than 0.1 mol/L; when the concentration of the acid solution is less than 0.1mol/L, the water absorption of the recycled aggregate is large and the apparent density is also low. The optimal acid solution concentration is 0.1mol/L from the viewpoint of the effect of water absorption and apparent density of the recycled aggregate.
When the acid solution is used for repairing the recycled aggregate in multiple stages, the soaking time has a great influence on the water absorption rate and the apparent density of the recycled aggregate, when the soaking time exceeds 2 days, the water absorption rate of the recycled aggregate does not decrease but tends to increase, and when the soaking time is less than 2 days, the water absorption rate of the recycled aggregate is higher and the apparent density is lower. The optimum choice is 2 days, from the viewpoint of the effect of water absorption and apparent density of the recycled aggregate.
As shown in the classification of the water absorption rate and the apparent density of the recycled coarse aggregate in the national standard GB/T25177-2010 in the table 3, the water absorption rate and the apparent density can reach the II-grade standard of the recycled coarse aggregate for the national standard GB/T25177-2010 concrete under the optimal condition, and the aggregate standard in the building engineering application is met.
Claims (4)
1. A method for reinforcing the quality of recycled coarse aggregate by adopting three stages of strong acid is characterized by comprising the following steps:
step 1, placing the recycled coarse aggregate in a hydrochloric acid solution and soaking for a period of time;
the concentration of the hydrochloric acid solution is 0.05 mol/L-0.20 mol/L;
the pH value range of the soaking solution is kept between 0.7 and 1.3;
step 2, adding a nitric acid solution into the hydrochloric acid solution soaked in the step 1 for a period of time, and taking out the regenerated coarse aggregate after soaking for a period of time;
the concentration of the nitric acid solution is 0.05 mol/L-0.20 mol/L;
the pH value range of the soaking solution is kept between 0.7 and 1.3;
step 3, putting the recycled coarse aggregate taken out in the step 2 into clear water for multiple times of cleaning, and taking out the recycled coarse aggregate until the clear water is neutral;
step 4, putting the recycled coarse aggregate taken out in the step 3 into a sulfuric acid solution, and taking out the recycled coarse aggregate after soaking for a period of time;
the concentration of the sulfuric acid solution is 0.05 mol/L-0.20 mol/L;
the pH value range of the soaking solution is kept between 0.4 and 1.0;
testing the pH value of the soaking solution once every two hours, and if the pH value is not in the target range, adding an acidic solution with the same type as the soaking solution to adjust the pH value of the soaking solution to the target range;
and 5, putting the recycled coarse aggregate taken out in the step 4 into clear water for multiple times of cleaning, and taking out the recycled coarse aggregate until the clear water is neutral, thereby obtaining the reinforced recycled coarse aggregate.
2. The method for reinforcing the quality of recycled coarse aggregates by using three stages of strong acids according to claim 1, wherein the soaking period in the steps 1, 2 and 4 is 1 to 5 days.
3. The method for reinforcing the quality of recycled coarse aggregates by using three stages of strong acids according to claim 1, wherein the recycled coarse aggregates comprise waste concrete, and the particle size fraction of the recycled coarse aggregates is 5mm to 30 mm.
4. The method for strengthening the quality of the recycled coarse aggregate in three stages by using the strong acid according to claim 1, wherein the acid solution is completely immersed in the recycled coarse aggregate during the soaking in the step 1 and the soaking in the step 2.
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| CN107721228A (en) * | 2017-10-09 | 2018-02-23 | 东南大学 | A kind of preparation method of hydrated calcium silicate early strength agent |
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| CN107721228A (en) * | 2017-10-09 | 2018-02-23 | 东南大学 | A kind of preparation method of hydrated calcium silicate early strength agent |
Non-Patent Citations (2)
| Title |
|---|
| "Durability of Reinforced Concrete Incorporating Recycled Concrete as Aggregate (RCA)";Ramtin Movassaghi;《A thesis presented to the University of Waterloo in fulfilment of the thesis requirement for the degree of Master of Applied Science in Mechanical Engineering》;20061231;52、76-77 * |
| "基于硫酸处理废弃混凝土骨料掺量不同对再生抗渗混凝土性能研究";王正一等;《建材与装饰》;20181031(第43期);177-178 * |
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