阅读说明：本技术 一种复合砂及其制备方法 (Composite sand and preparation method thereof ) 是由 郭玉林 王成启 徐志祥 练学标 刘磊 梁远博 张晓乐 方子善 万超群 于 2020-06-29 设计创作，主要内容包括：本申请的目的是提供一种复合砂及其制备方法,该复合砂是通过筛分将质量百分比为60～75％、细度模数为3.1～3.5的戈壁砂和质量百分比为25％～40％、细度模数为0.6～1.0沙漠砂混合均匀而得到,其中沙漠砂包括粒径为0.3～0.6mm第一沙漠砂、粒径为0.15～0.3mm第二沙漠砂和粒径为0～0.15mm第三沙漠砂,所述复合砂中第一沙漠砂的质量百分比为10～15％,第二沙漠砂的质量百分比为10～15％,第三沙漠砂的质量百分比为0～5％。所述复合砂解决了戈壁沙漠地区单一砂级配不良等问题,充分利用了戈壁沙漠地区闲置且丰富的砂源,解决了戈壁沙漠地区配制混凝土河沙资源短缺问题,降低了工程建设成本,起到了环境保护作用。(The composite sand is obtained by uniformly mixing 60-75% by mass of Gobi sand with a fineness modulus of 3.1-3.5 and 25-40% by mass of desert sand with a fineness modulus of 0.6-1.0 through screening, wherein the desert sand comprises first desert sand with a particle size of 0.3-0.6 mm, second desert sand with a particle size of 0.15-0.3 mm and third desert sand with a particle size of 0-0.15 mm, the first desert sand in the composite sand is 10-15% by mass, the second desert sand is 10-15% by mass and the third desert sand is 0-5% by mass. The composite sand solves the problems of poor single sand gradation and the like in the Gobi desert area, makes full use of idle and abundant sand sources in the Gobi desert area, solves the problem of resource shortage of prepared concrete river sand in the Gobi desert area, reduces the engineering construction cost, and plays a role in environmental protection.)

1. The preparation method of the composite sand is characterized in that 60-75% of Gobi sand with a fineness modulus of 3.1-3.5 and 25-40% of desert sand with a fineness modulus of 0.6-1.0 are uniformly mixed to obtain the composite sand.

2. The method of preparing composite sand according to claim 1, wherein the Gobi sand and the desert sand are obtained by a screening test.

3. The method for preparing composite sand according to claim 2, wherein the desert sand comprises a first desert sand with a particle size of 0.3 to 0.6mm, a second desert sand with a particle size of 0.15 to 0.3mm, and a third desert sand with a particle size of 0 to 0.15mm, and the composite sand comprises the first desert sand in an amount of 10 to 15% by mass, the second desert sand in an amount of 10 to 15% by mass, and the third desert sand in an amount of 0 to 5% by mass.

4. The composite sand is characterized by comprising Gobi sand and desert sand, wherein the fineness modulus of the Gobi sand is 3.1-3.5, the fineness modulus of the desert sand is 0.6-1.0, the mass percent of the Gobi sand in the composite sand is 60-75%, and the mass percent of the desert sand is 25-40%.

5. The composite sand of claim 4, wherein said desert sand consists of a first desert sand having a particle size of 0.3 to 0.6mm, a second desert sand having a particle size of 0.15 to 0.3mm, and a third desert sand having a particle size of 0 to 0.15 mm; the composite sand comprises, by mass, 10-15% of first desert sand, 15-20% of second desert sand and 0-5% of third desert sand.

6. The composite sand as claimed in claim 4, wherein the fineness modulus of the composite sand is 2.3-3.0, and the graded region of the composite sand conforms to region 2.

7. The composite sand of claim 4, wherein the Gobi sand and the desert sand have a mud content of less than 2.0%, a chloride content of less than 0.02%, a firmness factor of less than 8.0%, and a single-stage maximum crush value indicator of less than 25%.

8. The composite sand of claim 7 wherein the composite sand has a mud content of less than 2.0%, a chloride content of less than 0.02%, a firmness factor of less than 8.0%, and a single-stage maximum crush value indicator of less than 25%.

Technical Field

The invention relates to the field of engineering construction, in particular to composite sand and a preparation method thereof.

Background

In recent years, with the development of national economy of China, infrastructure construction has come to an unprecedented development. Concrete is a preferred material for various civil engineering constructions, and building sand is used as one of important components of the concrete, and the using amount is very large. At present, the annual demand of engineering sand in China is about billions of tons, and no matter the sand resource is considered from the aspects of economy, quality, reserves or sustainable development, the requirement of the modern engineering construction scale cannot be met.

In addition, the country has increased strength and scale for infrastructure construction in the western region. River sand resources in western regions of China are in shortage, but rich and low-cost Gobi sand, desert sand and other resources exist, wherein in the process of sand washing and mud removing of the Gobi sand, powder with the particle size smaller than 0.075mm and even fine particles with the particle size larger than 0.15mm are removed, so that the Gobi sand is large in fineness modulus and large in number of clumsy edges and corners and belongs to coarse sand; the desert sand has small fineness modulus, more components with the particle size smaller than 0.3mm, belongs to superfine sand and single gradation, and the concrete prepared by the two kinds of sand has poor workability, cannot meet the construction performance, causes poor appearance quality of the poured concrete member and has potential safety hazard.

Therefore, how to prepare the composite sand suitable for the concrete preparation in the gobi desert area by utilizing the existing sand resources in the gobi desert area is a difficult problem in the construction process of the buildings in the western gobi desert area at present.

Disclosure of Invention

In order to solve the technical problem, the application provides a preparation method of composite sand, and the preparation method of the composite sand comprises the following steps:

uniformly mixing 60-75% of Gobi sand with a fineness modulus of 3.1-3.5 and 25-40% of desert sand with a fineness modulus of 0.6-1.0 by mass percent to obtain the composite sand.

Further, the gobi sand and the desert sand are obtained through a screening test.

Further, the desert sand comprises first desert sand with the particle size of 0.3-0.6 mm, second desert sand with the particle size of 0.15-0.3 mm and third desert sand with the particle size of 0-0.15 mm, wherein the mass percentage of the first desert sand in the composite sand is 10-15%, the mass percentage of the second desert sand is 10-15%, and the mass percentage of the third desert sand is 0-5%.

The composite sand is suitable for preparing concrete in a Gobi desert area, and consists of Gobi sand and desert sand, wherein the fineness modulus of the Gobi sand is 3.1-3.5, the fineness modulus of the desert sand is 0.6-1.0, the mass percent of the Gobi sand in the composite sand is 60-75%, and the mass percent of the desert sand is 25-40%.

Further, the desert sand consists of a first desert sand, a second desert sand and a third desert sand, wherein the particle size of the first desert sand is 0.3-0.6 mm, the particle size of the second desert sand is 0.15-0.3 mm, and the particle size of the third desert sand is 0-0.15 mm; the composite sand comprises, by mass, 10-15% of first desert sand, 15-20% of second desert sand and 0-5% of third desert sand.

Furthermore, the fineness modulus of the composite sand is 2.3-3.0, and the grading area of the composite sand accords with the 2 area.

Further, the content of the mud in the Gobi sand and the desert sand is lower than 2.0%, the content of chloride is lower than 0.02%, the firmness coefficient is lower than 8.0%, and the single-stage maximum crush value index is lower than 25%.

Further, the mud content of the composite sand is lower than 2.0%, the chloride content is lower than 0.02%, the firmness coefficient is lower than 8.0%, and the single-stage maximum crushing value index is lower than 25%.

Compared with the prior art, the method has the following beneficial effects:

mix the different gobi sand of granule fineness and desert sand according to certain mass ratio in this application, prepare compound sand, the addition of desert sand has compensatied obviously through adding desert sand component to the gobi sand, compensatied the fine particle composition of gobi sand disappearance, and the fine particle can play and fill the space between the gobi sand granule, optimizes the effect of the gradation of gobi sand, has solved the bad scheduling problem of the single sand in gobi desert area.

The method and the device follow the principle of taking materials locally and reasonably developing and utilizing natural resources according to local conditions, make full use of idle and abundant sand sources in the gobi desert area, replace river sand used by traditional concrete in a full proportion, solve the problem of shortage of prepared concrete river sand resources in the gobi desert area, reduce the engineering construction cost and play a role in environmental protection.

Detailed Description

The present application is described in further detail below by way of examples.

The following examples are only preferred embodiments of the present application, and are not intended to be exhaustive. Based on the embodiments in the embodiment, other embodiments obtained by those skilled in the art without any creative efforts shall fall into the protection scope of the present application.

In some embodiments of the present application, the sand source is gobi sand produced by a gobi desert sand production plant in Xinjiang, or river sand produced in a desert in Takrama and a river sand produced in a river in Yangtze river, according to the standard technical requirements of "Sand for construction" (GB/T14684-2011) at normal temperature and pressure. The following data were obtained by selecting square mesh sieves having nominal diameters of 5.00mm, 2.50mm, 1.25mm, 630 μm, 315 μm and 160 μm, respectively, and performing a sieving test on the Gobi sand, the desert sand and the river sand, and measuring indices of mud content, chloride content and single-stage maximum crush value of the Gobi sand, the desert sand and the river sand, as shown in Table 1.

TABLE 1 Gobi sand, desert sand and river sand test data recording sheet

As can be seen from table 1, the gobi sand has more coarse particles and less fine particles; in contrast, the desert sand has more fine particles, no larger particles and single gradation.

Thus, to ensure that the composite sand gradation zone is as close as possible to zone 2, the oversize A is accumulated from the coarsest grains of Gobi sand₂And the content of the residual tray bottom is known, the ratio of the gobi sand is equal to or less than 75 percent, the ratio of the third desert sand is equal to or less than 5 percent, and the formula is calculated according to the proportion of the composite sand:

a+b+c+d＝1 (1)

P_n≤a×A_n+b×B_n+c×C_n≤Q_n(n＝1-6) (2)

in the formula: a. b, c and d are respectively the weight percentage of the Gobi sand, the first desert sand, the second desert sand and the third desert sand in the total amount of the composite sand, and the screen residue A is accumulated by the coarsest particles of the Gobi sand₂And the content of the residual tray bottom is less than or equal to 75 percent of a and less than or equal to 5 percent of d; p_n、Q_n(n-1-6) are square-hole sieves with nominal diameters of 5.00mm, 2.50mm, 1.25mm, 630 μm, 315 μm and 160 μm, respectively, and the cumulative lower and upper screen residue limits are set for the sand grading in the zone II; a. the_n(n-1-6) is the cumulative screen residue of Gobi sand on a square-hole screen with nominal diameter of 5.00mm, 2.50mm, 1.25mm, 630 μm, 315 μm and 160 μm; b5 and C6 are respectively first desert sand and second desert sandThe sand is accumulated on a square hole sieve with the nominal diameter of 315 mu m and the nominal diameter of 160 mu m, B₅＝B₆＝C₆When n is another value, B is 100%_n、C_nIs 0.

Substituting the data in the table 1 into the formulas (1) and (2), and calculating to obtain 60-75% of gobi sand, 10-15% of first desert sand, 15-20% of second desert sand and less than or equal to 0-5% of third desert sand in the composite sand.

In this embodiment, the gobi sand, the first desert sand, the second desert sand, and the third desert sand are mixed in the mass percentage range. And uniformly mixing the Gobi sand, the first desert sand, the second desert sand and the third desert sand according to the mass percentage in the table 2 to obtain the composite sand 1, the composite sand 2, the composite sand 3 and the composite sand 4. The compounding manner of the actual gobi sand, the first desert sand, the second desert sand and the third desert sand is not limited thereto.

TABLE 2 compounding ratio of the compound sands of the four examples

Four examples	Gobi sand/%)	First desert sand/%)	Second desert sand/%)	Third desert sand/%)
					Composite sand 1	60	15	20	5
Composite sand 2	75	10	15	0
					Composite sand 3	65	14	18	3
Composite sand 4	70	12	16	2

The composite sand 1, the composite sand 2, the composite sand 3 and the composite sand 4 prepared in table 2 were subjected to a screening test using square-hole sieves having nominal diameters of 5.00mm, 2.50mm, 1.25mm, 630 μm, 315 μm and 160 μm, respectively, and specified and calibrated for the sludge content, chloride content and single-stage maximum crush value of the four composite sands, with the test results shown in table 3.

Table 3 data recording table of compound sand test of four examples

It can be found that: the fineness modulus of the four types of composite sand is 2.3-3.0, the grading region meets the requirement of the 2 region, the mud content of the composite sand is lower than 2.0%, the chloride content is lower than 0.02%, the firmness is lower than 8.0%, the maximum crushing index of a single stage is lower than 25%, and the performance of the prepared composite sand meets the standard of construction sand (GB/T14684-2011). Compared with the common river sand, the prepared composite sand fully utilizes the gobi desert resources, saves the cost and is beneficial to the economic development of the western gobi areas.

In the embodiment, the percentages of the Gobi sand and the desert sand are calculated through a simplified composite sand preparation calculation formula, the preparation method of the composite sand is simplified, the method is scientific and operable, and the actual production of the composite sand in the West Gobi desert area is easy.

According to one aspect of the application, the composite sand is composed of Gobi sand and desert sand, wherein the fineness modulus of the Gobi sand is 3.1-3.5, the fineness modulus of the desert sand is 0.6-1.0, the mass percent of the Gobi sand in the composite sand is 60-75%, and the mass percent of the desert sand is 25% -40%.

In the Gobi desert area, the Gobi sand and the desert sand have numerous resources, the composite sand is formed by mixing the Gobi sand and the desert sand which are common in the Gobi desert area according to a certain mass percentage, the fineness modulus of the Gobi sand is large, the fineness modulus of the desert sand is small, and the gradation is single, so that the construction performance cannot be met by singly using the Gobi sand or singly using the desert sand to manufacture concrete. After the Gobi sand and the desert sand are mixed according to a certain mass percentage, the desert sand component is mixed into the Gobi sand, so that the fine particle component missing in the Gobi sand is made up, and the compactness of the prepared concrete can be improved. The method and the device follow the principle of using local materials and reasonably developing and utilizing natural resources according to local conditions, make full use of idle and abundant sand sources in the gobi desert area, and solve the problem of shortage of prepared concrete river sand resources in the gobi desert area.

According to the embodiment, the Gobi sand and the desert sand are mixed according to a certain proportion, the fineness modulus of the composite sand is 2.3-3.0, the grading area of the composite sand meets 2 areas, and the standard technical requirements of construction sand (GB/T14684-2011) are met.

In some embodiments of the present application, the desert sand is composed of a first desert sand having a particle size of 0.3 to 0.6mm, a second desert sand having a particle size of 0.15 to 0.3mm, and a third desert sand having a particle size of 0 to 0.15 mm; the composite sand comprises 10-15% of first desert sand, 10-15% of second desert sand and 0-5% of third desert sand by mass percentage. By adding the desert sand components with different particle sizes into the Gobi sand, the fine particle components such as 0.075mm, 0.15mm and 0.3mm which are lost in the Gobi sand are made up, and the fine particles of the desert sand can fill gaps among the Gobi sand particles, so that the compactness of the prepared composite sand concrete is correspondingly improved, and the mechanical property and the durability of the composite sand concrete are obviously improved.

The composite sand provided by the application is suitable for sand for concrete engineering in the Gobi desert area, and the problem of resource shortage of prepared concrete river sand in the Gobi desert area is solved.

In one embodiment of the present application, the Gobi sand and desert sand have a silt content of less than 2.0%, a chloride content of less than 0.02%, a firmness factor of less than 8.0%, and a single-stage maximum crush value indicator of less than 25%.

In the examples described above, the composite sand has a mud content of less than 2.0%, a chloride content of less than 0.02%, a firmness factor of less than 8.0% and a single-stage maximum crush value index of less than 25%.

The above embodiments are merely to illustrate the technical solutions of the present invention, not to limit the present invention, and the present invention has been described in detail with reference to the preferred embodiments. It will be understood by those skilled in the art that various modifications and equivalent arrangements may be made without departing from the spirit and scope of the present invention as defined in the appended claims.