Copper-doped tailing pavement base material as well as proportion confirmation method and application thereof

Abstract

The invention belongs to the technical field of road construction, and particularly relates to a copper-doped tailing pavement base material as well as a proportion confirmation method and application thereof. The preparation method comprises the following steps: S1, preparing raw materials; s2, a compaction test method is adopted, and the void ratio of the compacted aggregate wrapped with the cement mortar is calculated; s3, according to the volume filling principle, the gravels form a basic framework, the void ratio of the gravels in the compaction state is measured, cement adhesive cement adheres to aggregate, the aggregate is filled in gaps of the framework formed by the gravels, and finally the blending proportion of the copper tailings, the gravels and the aggregate is determined by combining the composition mechanism and volume parameters of the mixture; and S4, calculating the using amount of the steel slag composite cementing material mucilage according to the thickness of the steel slag composite cementing material mucilage wrapping film and the specific surface area of the copper tailings. A skeleton filling theoretical method is adopted, the shrinkage effect of the filler in the skeleton is controlled, the cracking risk is reduced, and meanwhile the high strength is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of road construction, and in particular relates to a copper-doped tailings pavement base material and a method for confirming its proportion and application thereof. Background Art

[0002] Copper tailings refer to the solid waste remaining after the useful components in the ore are screened out after the mines that mainly mine copper resources are processed by the mineral processing technology. Usually, more than 98% of the components in the copper ore are refined and become tailings. With the rapid development of highways, the demand for road construction materials is increasing. The geometric shape and mechanical properties of copper tailings are similar to those of rolled crushed stone, and they can replace natural aggregates. Applying tailings to road materials is a good trend to achieve waste utilization and environmental protection.

[0003] Most of the existing high-grade highway pavement bases use semi-rigid bases. Semi-rigid base materials require high early strength, good plate properties, and strong diffusion stress. Affected by the thermal reaction of cement hydration, the shrinkage cracking and damage problems of semi-rigid base materials have been difficult to solve. Among them, in semi-rigid base materials, the finer the material, the larger the specific surface area, and the more cement mortar is needed to wrap its surface, but shrinkage cracking is more likely to occur. Therefore, there is an urgent need for a copper tailings-doped pavement base material and its ratio confirmation method and application to solve the above problems. Summary of the invention

[0004] In order to overcome the defects in the above-mentioned prior art, the present invention provides a copper-doped tailings pavement base material and a method and application thereof for determining its proportion. The present invention adopts a skeleton filling theory method and controls the shrinkage effect of the fine material used for filling in the skeleton and the bonding material after the action of the bonding material through the thickness of the mortar film and the selection of the bonding material, thereby reducing the risk of cracking and having good strength.

[0005] To achieve one of the above objects, the present invention provides a method comprising the following steps: S1. Prepare raw materials: cement mortar, copper tailings, 26.5-37.5 mm crushed stone, 0-5 mm aggregate, 5-10 mm aggregate and steel slag composite cementitious material mortar; S2. Screen the aggregates of 0~5mm and 5~10mm, and mix them according to the grading range requirements to determine the ratio of 0~5mm aggregates to 5~10mm aggregates; then calculate the amount of cement mortar according to the thickness of the cement mortar film, the specific surface area of ​​0~5mm aggregates and the specific surface area of ​​5~10mm aggregates; then use the compaction test method to calculate the void ratio of the aggregates of 0~5mm and 5~10mm wrapped with cement mortar after compaction; S3. According to the volume filling principle, crushed stones of 26.5~37.5mm form the basic skeleton, and the porosity of crushed stones of 26.5~37.5mm under vibration is measured; cement mortar is used to bond aggregates of 0~5mm and aggregates of 5~10mm, and then filled into the voids of the skeleton formed by crushed stones of 26.5~37.5mm; finally, copper tailings are bonded by iron slag composite gel material and filled into the remaining voids; the voids after copper tailings filling are the designed porosity of copper tailings-added pavement base material; the blending ratio of copper tailings, crushed stones of 26.5~37.5mm, aggregates of 0~5mm and aggregates of 5~10mm is determined in combination with the composition mechanism and volume parameters of the mixture; S4. Calculate the amount of the steel slag composite cementitious material mortar based on the thickness of the steel slag composite cementitious material mortar film and the specific surface area of ​​the copper tailings.

[0006] Preferably, the amount of cement mortar and the porosity in step S2 are calculated according to the following formulas: ; ; ; ; Where: S ——Specific surface area of ​​aggregate, m 2 / kg; a——the passing rate of aggregate on the 4.75mm sieve; b——the passing rate of aggregate on the 2.36mm sieve; c – the passing rate of aggregates through a 1.18 mm sieve; d——the passing rate of aggregate in 0.6mm sieve hole; e——the passing rate of aggregate in 0.3mm sieve hole; f——the passing rate of aggregate in 0.15mm sieve hole; g——the passing rate of aggregate in the 0.075mm sieve; K sj ——The proportion of cement mortar used in compaction test, %; K 0~5 ——When aggregates are graded, the proportion of aggregates with a diameter of 0 to 5 mm is %; S 0~5 ——Specific surface area of ​​aggregate with a diameter of 0 to 5 mm, m 2 / kg; S 5~10 ——Specific surface area of ​​aggregates 5 to 10 mm, m2 / kg; u sj ——Thickness of cement mortar film, μm; r sj ——density of cement mortar, g / cm 3 ; r hc ——Combined density of 0-5mm aggregate and 5-10mm aggregate wrapped with cement mortar, g / cm 3 ; r 0~5 ——Apparent density of aggregate with particle size of 0 to 5 mm, g / cm 3 ; r 5~10 ——Apparent density of aggregate with particle size of 5 to 10 mm, g / cm 3 ; r js ——Compacted density of 0-5mm aggregate and 5-10mm aggregate wrapped with cement mortar, g / cm 3 ; VC ——The void ratio of 0-5mm aggregate and 5-10mm aggregate wrapped with cement mortar after compaction, %.

[0007] Preferably, the blending ratios of copper tailings, crushed stone of 26.5-37.5 mm, aggregate of 0-5 mm, and aggregate of 5-10 mm are calculated respectively according to the following formulas: ; ; ; ; Where: VAC ——Porosity of 26.5~37.5mm crushed stone after compaction, %; ρ d ——Vibrated density of crushed stone with a diameter of 26.5~37.5 mm, g / cm 3 ; ρ g ——Apparent density of crushed stone with a diameter of 26.5-37.5 mm, g / cm 3 ; V d ——1m 3 The volume of 26.5~37.5mm crushed stone in the road base material, m 3 ; V 0~5 ——1m 3 The volume of 0~5mm aggregate in the pavement base material, m 3 ; V 5~10 ——1m 3 The volume of 5-10 mm aggregate in the pavement base material, m 3 ; V w ——1m 3 Volume of copper tailings in pavement base material, m 3 ; V sj ——1m 3 Volume of cement paste in pavement base material, m 3 ; V gj ——1m 3 Volume of steel slag composite cementitious material mortar in pavement base material, m 3 ; VV ——Designed void ratio of copper tailings-mixed pavement base material, %; VC ——The void ratio of 0-5mm aggregate and 5-10mm aggregate wrapped with cement mortar after compaction, %.

[0008] Preferably, the amount of the steel slag composite cementitious material mortar is calculated according to the following formula: ; ; Where: r——average particle size of copper tailings, mm; ——Sieve hole size, mm; r i+1 ——Size of the sieve hole of the previous sieve of the i-th sieve, mm; Q i ——Copper tailings in the sieve hole The sieve residue, % V gj ——1m 3 Volume of steel slag composite cementitious material mortar in the pavement base material, m 3 ; V w ——1m 3 Volume of copper tailings in pavement base material, m3 ; ——Thickness of slurry film of steel slag composite cementitious material, mm.

[0009] Preferably, the designed void ratio of the copper-doped tailings pavement base material is 2-5%.

[0010] Preferably, the water-cement ratio in the cement mortar is 0.4-0.6, and the cement mortar film thickness is 15-20 um.

[0011] Preferably, the water-to-cement ratio of the iron slag composite gel material mortar in the copper tailings-doped pavement base material is 0.35-0.55, and the thickness of the iron slag composite gel material mortar film is 0.006-0.01 mm.

[0012] To achieve the second of the above purposes, the present invention provides a pavement base material obtained by a method for confirming the proportion of a copper tailings-doped pavement base material, the material comprising cement mortar, copper tailings, 26.5-37.5 mm crushed stone, 0-5 mm aggregate, 5-10 mm aggregate and steel slag composite cementitious material mortar.

[0013] To achieve the third purpose above, the present invention provides an application of a copper-doped tailings pavement base material, comprising the following steps: (1) Determine the proportion of copper-doped tailings pavement base material and prepare the copper-doped tailings pavement base material; (2) Sprinkle water on the 26.5-37.5 mm crushed stones until the surface is moist, and use a paver to spread the 26.5-37.5 mm crushed stones; (3) At the mixing station, mix cement mortar with 0-5 mm aggregate and 5-10 mm aggregate to prepare filler I. According to the designed mix ratio and the crushed stone paving thickness of 26.5-37.5 mm, determine the paving thickness of the filler, and use an excavator in combination with manual paving; (4) The copper tailings and the steel slag composite cementitious material mortar are mixed at the mixing station to prepare filler II. The paving thickness of filler II is determined according to the designed proportion and the crushed stone paving thickness of 26.5-37.5 mm, and an excavator is used in combination with manual paving; (5) The road mixing equipment used is used to mix the crushed stone with filler material I and filler material II 1 to 2 times; (6) Use a vibratory roller to vibrate and roll the surface 4 to 6 times, and then use a rubber-wheel roller to roll the surface 2 to 3 times.

[0014] Preferably, the tonnage of the vibratory roller is greater than 22 t.

[0015] The advantages of the present invention are: (1) The present invention uses large-size crushed stone as the basic skeleton, and then uses cement mortar to bind crushed stone and fill it in the gaps of the crushed stone skeleton. Then, iron slag composite gel material is used to bind copper tailings and fill them in the remaining gaps. This method adopts the volume step-by-step filling principle, controls the proportion of each raw material, uses different types of binders to bind copper tailings and crushed stone, controls the amount of binder by the film thickness of crushed stone and copper tailings, reduces the impact of shrinkage effect, thereby reducing the risk of cracking, and the road base material has better strength.

[0016] (2) The present invention accurately calculates the amount of binder by the film-forming angle of crushed stone and copper tailings, thereby giving full play to the optimal effect of the mortar material, while avoiding the shrinkage effect caused by excessive use of the mortar material, and further reducing the material cost.

[0017] (3) The present invention uses different types of binders to bind copper tailings and gravel. Cement mortar is used for gravel, so that the gravel has a higher bonding strength, the contact surface area of ​​the copper tailings is larger, and it is more likely to shrink. Iron and steel slag composite binder mortar with low hydration heat is used to bind copper tailings, which reduces the surface shrinkage effect of the copper tailings and effectively reduces the risk of cracks. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0019] Example 1 (1) Determine the proportion of the base material of the copper tailings road surface: The base materials of the copper tailings-added road surface include: cement mortar, copper tailings, 26.5-37.5 mm crushed stone, 0-5 mm aggregate, 5-10 mm aggregate, and steel slag composite cementitious material mortar. The copper tailings, 0-5 mm aggregate, and 5-10 mm aggregate are screened, and the results are shown in Table 1 below: Table 1 Raw material screening results ; Table 2 Density of raw materials ; According to the grading range required by the specification, the aggregate grading is carried out. According to the grading range specified in the specification, the blending proportion of each grade of aggregate is determined as shown in Table 3 below: Table 3 ; The specific surface area of ​​aggregates of 0 to 5 mm and 5 to 10 mm is calculated according to the following formula: =2.18kg / m 2 ; =10.12kg / m 2 ; ; The thickness of cement mortar film is 18um, and the amount of cement mortar is calculated according to the following formula: =11.9%; ; 30% of 0-5mm aggregate, 70% of 5-10mm aggregate and 13.4% cement mortar were compacted to determine their compaction density. g / cm 3 , calculate the void ratio of 5-10mm aggregate and 0-5mm aggregate after compaction by cement mortar: = 2.586g / cm 3 ; =32%; According to the volume filling principle, the crushed stones with a diameter of 26.5-37.5 mm form the basic skeleton. The density of the crushed stones with a diameter of 26.5-37.5 mm under vibration is measured. g / cm 3 , the void fraction is calculated as follows: =45.4%; Cement mortar wraps aggregates with particle sizes of 0-5mm and 5-10mm, and fills them in the gaps of the skeleton. Finally, copper tailings are wrapped by iron slag composite gel material mortar and filled in the remaining gaps. The gaps after the copper tailings are filled are the designed void ratio of the copper tailings-added pavement base material, which is 3%. Combined with the composition mechanism and volume parameters of the mixture, the mixing ratio of copper tailings, 26.5-37.5mm crushed stone, 0-5mm aggregate, and 5-10mm aggregate is calculated according to the following formula.

[0020] ; ; ; The thickness of the steel slag composite cementitious material mortar film is 0.008mm. According to the screening results of copper tailings, the amount of steel slag composite cementitious material mortar is calculated according to the following formula: 0.187mm; = 0.279 ; Combining the above equations, after calculating 1m 3 The amount of crushed stone with a diameter of 26.5-37.5 mm in the copper tailings-added road base material is 0.546 m 3 , 0~5mm aggregate usage 0.081m 3 , the amount of aggregate of 5 to 10 mm is 0.19 m 3 , the amount of cement mortar is 0.036m 3 , the amount of copper tailings is 0.09m 3 The amount of steel slag composite cementitious material mortar is 0.025m 3 .

[0021] According to the above ratio, 0-5 mm aggregate, 5-10 mm aggregate and cement mortar are mixed to prepare filler I, the water-binder ratio of cement mortar is 0.5, and copper tailings and steel slag composite cementitious material mortar are mixed to prepare filler II, the water-binder ratio of steel slag composite cementitious material mortar is 0.45, and the 7d unconfined compressive strength test results are shown in Table 4 below: Table 4 7d unconfined compressive strength test results of filler (MPa) ; It can be seen from Table 4 that the experimental results of the present invention meet the specification requirements.

[0022] (2) The construction steps of copper tailings-doped road base material are as follows: 1) The design thickness is 20cm, the loose paving coefficient is 1.3, first sprinkle water on the 26.5~37.5mm crushed stones until the surface is moist, and then use a paver to spread the 26.5~37.5mm crushed stones.

[0023] 2) At the mixing station, according to the mix design results, cement mortar is mixed with 5-10mm aggregate and 0-5mm aggregate to prepare filler I. It is spread with crushed stone of 26.5~37.5mm and the thickness is 20×1.3=26cm. The paving thickness of filler I is determined as: 26×0.308 / 0.546=14.7cm. An excavator is used in combination with manual paving.

[0024] 3) According to the mix ratio design results, the copper tailings and the steel slag composite cementitious material mortar are mixed at the mixing station to prepare filler II, and 26.5~37.5mm crushed stone is spread with a thickness of 26cm. The spreading thickness of filler II is determined to be 26×0.115 / 0.546=5.5cm, and an excavator is used in combination with manual spreading.

[0025] 4) Use road mixing equipment to mix the crushed stone with the filler material I and filler material II once.

[0026] 5) Use a 25t vibratory roller to vibrate and roll the surface 5 times, and a rubber-wheel roller to perform static rolling 2 times.

[0027] After the construction is completed, curing is carried out and core sampling is performed to determine its compaction and strength, which is the requirement for heavy traffic base of expressways and first-class highways. The results are shown in Table 5 below: Table 5 Test results of copper tailings-doped road base materials after construction ; It can be seen from Table 5 that the copper-doped tailings pavement base material prepared by the present invention meets the specification requirements.

[0028] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for confirming the proportion of copper-doped tailings road base material, characterized in that: The steps include: S1. Prepare raw materials: cement mortar, copper tailings, 26.5-37.5 mm crushed stone, 0-5 mm aggregate, 5-10 mm aggregate and steel slag composite cementitious material mortar; S2. Screen the aggregates of 0~5mm and 5~10mm, and mix them according to the grading range requirements to determine the ratio of 0~5mm aggregates to 5~10mm aggregates; then calculate the amount of cement mortar according to the thickness of the cement mortar film, the specific surface area of ​​0~5mm aggregates and the specific surface area of ​​5~10mm aggregates; then use the compaction test method to calculate the void ratio of the aggregates of 0~5mm and 5~10mm wrapped with cement mortar after compaction; S3. According to the volume filling principle, crushed stones of 26.5~37.5mm form the basic skeleton, and the porosity of crushed stones of 26.5~37.5mm under vibration is measured; cement mortar is used to bond aggregates of 0~5mm and aggregates of 5~10mm, and then filled into the voids of the skeleton formed by crushed stones of 26.5~37.5mm; finally, copper tailings are bonded by iron slag composite gel material and filled into the remaining voids; the voids after copper tailings filling are the designed porosity of copper tailings-added pavement base material; the blending ratio of copper tailings, crushed stones of 26.5~37.5mm, aggregates of 0~5mm and aggregates of 5~10mm is determined in combination with the composition mechanism and volume parameters of the mixture; S4. Calculate the amount of the steel slag composite cementitious material mortar based on the thickness of the steel slag composite cementitious material mortar film and the specific surface area of ​​the copper tailings.

2. The method for confirming the proportion of a copper-doped tailings road base material according to claim 1, characterized in that: The amount of cement mortar and the porosity in step S2 are calculated according to the following formulas: ； ； ； ； Where: S ——Specific surface area of ​​aggregate, m 2 / kg; a——the passing rate of aggregate on the 4.75mm sieve; b——the passing rate of aggregate on the 2.36mm sieve; c – the passing rate of aggregates through a 1.18 mm sieve; d——the passing rate of aggregate in 0.6mm sieve hole; e——the passing rate of aggregate in 0.3mm sieve hole; f——the passing rate of aggregate in 0.15mm sieve hole; g——the passing rate of aggregate in the 0.075mm sieve; K sj ——The proportion of cement mortar used in compaction test, %; K 0~5 ——When aggregates are graded, the proportion of aggregates with a diameter of 0 to 5 mm is %; S 0~5 ——Specific surface area of ​​aggregate with a diameter of 0 to 5 mm, m 2 / kg; S 5~10 ——Specific surface area of ​​aggregates 5 to 10 mm, m 2 / kg; u sj ——Thickness of cement mortar film, μm; ρ sj ——density of cement mortar, g / cm 3 ; ρ hc ——Combined density of 0-5mm aggregate and 5-10mm aggregate wrapped with cement mortar, g / cm 3 ; ρ 0~5 ——Apparent density of aggregate with particle size of 0 to 5 mm, g / cm 3 ; ρ 5~10 ——Apparent density of aggregate with particle size of 5 to 10 mm, g / cm 3 ; ρ js ——Compacted density of 0-5mm aggregate and 5-10mm aggregate wrapped with cement mortar, g / cm 3 ; VC ——The void ratio of 0-5mm aggregate and 5-10mm aggregate wrapped with cement mortar after compaction, %.

3. The method for confirming the proportion of a copper-doped tailings road base material according to claim 1, characterized in that: The blending ratios of copper tailings, 26.5-37.5 mm crushed stone, 0-5 mm aggregate, and 5-10 mm aggregate are calculated according to the following formulas: ； ； ； ； Where: VAC ——Porosity of 26.5~37.5mm crushed stone after compaction, %; ρ d ——Vibrated density of crushed stone with a diameter of 26.5~37.5 mm, g / cm 3 ; ρ g ——Apparent density of crushed stone with a diameter of 26.5-37.5 mm, g / cm 3 ; V d ——1m 3 The volume of 26.5~37.5mm crushed stone in the road base material, m 3 ; V 0~5 ——1m 3 The volume of 0~5mm aggregate in the pavement base material, m 3 ; V 5~10 ——1m 3 The volume of 5-10 mm aggregate in the pavement base material, m 3 ; V w ——1m 3 Volume of copper tailings in pavement base material, m 3 ; V sj ——1m 3 Volume of cement paste in pavement base material, m 3 ; V gj ——1m 3 Volume of steel slag composite cementitious material mortar in pavement base material, m 3 ; VV ——Designed void ratio of copper tailings-mixed pavement base material, %; VC ——The void ratio of 0-5mm aggregate and 5-10mm aggregate wrapped with cement mortar after compaction, %.

4. The method for confirming the proportion of a copper-doped tailings road base material according to claim 1, characterized in that: The dosage of steel slag composite cementitious material mortar is calculated according to the following formula: ； ； Where: r——average particle size of copper tailings, mm; ——Sieve hole size, mm; r i+1 ——Size of the sieve hole of the previous sieve of the i-th sieve, mm; Q i ——Copper tailings in the sieve hole The sieve residue, % V gj ——1m 3 Volume of steel slag composite cementitious material mortar in the pavement base material, m 3 ; V w ——1m 3 Volume of copper tailings in pavement base material, m 3 ; ——Thickness of steel slag composite cementitious material mortar film, mm.

5. The method for confirming the proportion of a copper-doped tailings road base material according to claim 1, characterized in that: The copper-doped tailings pavement base material has a designed void ratio of 2-5%.

6. The method for confirming the proportion of a copper-doped tailings road base material according to claim 1, characterized in that: The water-cement ratio in the cement mortar is 0.4-0.6, and the thickness of the cement mortar film is 15-20 um.

7. The method for confirming the proportion of a copper-doped tailings road base material according to claim 1, characterized in that: The water-to-binder ratio of the iron slag composite gel material mortar in the copper tailings-doped road base material is 0.35-0.55, and the film thickness of the iron slag composite gel material mortar is 0.006-0.01 mm.

8. The pavement base material obtained by the method for determining the proportion of a copper-doped tailings pavement base material according to any one of claims 1 to 7, characterized in that: The material includes cement mortar, copper tailings, crushed stones of 26.5-37.5 mm, aggregates of 0-5 mm, aggregates of 5-10 mm and steel slag composite cementitious material mortar.

9. The use of a copper-doped tailings pavement base material as claimed in claim 8, characterized in that: The steps include: (1) Determine the proportion of copper-doped tailings pavement base materials and prepare copper-doped tailings pavement base materials; (2) Sprinkle water on the 26.5-37.5 mm gravel until the surface is moist, and use a paver to spread the 26.5-37.5 mm gravel; (3) At the mixing station, mix cement mortar with 0-5 mm aggregate and 5-10 mm aggregate to prepare filler I. According to the designed mix ratio and the crushed stone paving thickness of 26.5-37.5 mm, determine the paving thickness of the filler, and use an excavator in combination with manual paving; (4) The copper tailings and the steel slag composite cementitious material mortar are mixed at the mixing station to prepare filler II. The paving thickness of filler II is determined according to the designed proportion and the crushed stone paving thickness of 26.5-37.5 mm, and an excavator is used in combination with manual paving; (5) The road mixing equipment used is used to mix the crushed stone with filler material I and filler material II 1 to 2 times; (6) Use a vibratory roller to vibrate and roll the surface 4 to 6 times, and then use a rubber-wheel roller to roll the surface 2 to 3 times.

10. The use of a copper-doped tailings pavement base material according to claim 9, characterized in that: The tonnage of the vibratory roller is greater than 22t.

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