1. A method for producing ready-mixed concrete by using stone sawn mud is characterized by comprising the following steps:

after the saw mud is pretreated, saw mud particles with the water content of 20-35%, the methylene blue value less than 1.0, the sand content of 15-25% and the dust content of 40-65% are selected, the saw mud particles are used for replacing coal ash and fine sand, part or all of the coal ash is replaced in the proportion, the rest of the saw mud particles are used for replacing part of the sand, and the proportion of the saw mud is set according to the principle that the volume weight is not changed before and after the replacement.

2. The method for producing ready-mixed concrete using stone saw mud according to claim 1, wherein the pre-treatment step comprises screening the saw mud to remove impurities, and scattering and rolling the treated saw mud to obtain saw mud particles having a looseness of 2.0-3.0;

the calculation formula of the looseness is as follows:

wherein K is the loosening coefficient of the sawn mud;

V₂-the bulk of the sawn mud after breaking up and rolling;

V₁the loose volume of the saw mud before breaking up and rolling.

3. The method for producing ready-mixed concrete using stone sawn mud according to claim 1, wherein the selected sawn mud particles have a maximum particle size of less than 15 mm.

4. The method for producing the ready-mixed concrete by using the stone sawn mud according to claim 1, wherein the ready-mixed concrete is obtained by adding and stirring a cementing material, sand, sawn mud particles, broken stones, water and an additive according to a raw material ratio:

300 portions of cementing material

750 portions of sand and 900 portions of

100 portions of sawn mud particles

950 portions of gravel and 1100 portions of sand

160 portions of water

5-15 parts of a water reducing agent.

5. The method for producing ready-mixed concrete using stone saw mud according to claim 4, wherein the gel material comprises portland cement, fine slag powder, fly ash.

6. The method for producing ready-mixed concrete using stone saw mud according to claim 5, wherein the portland cement strength grade is not lower than PO 42.5; the type of the slag micro powder is not lower than S75.

7. The method for producing ready-mixed concrete by using stone saw mud as claimed in claim 5, wherein the fly ash is class II or above fly ash.

8. The method for producing ready-mixed concrete using stone saw mud according to claim 4, wherein the sand is mixed medium sand composed of washing machine-made sand and river sand, the fineness modulus is 2.5-2.9, and the methylene blue value is less than 1.5.

9. The method for producing ready-mixed concrete using stone saw mud according to claim 4, wherein the crushed stone has a particle size of 5 to 31.5 mm.

10. The method for producing ready-mixed concrete by using stone saw mud as claimed in claim 4, wherein the water reducing agent is a polycarboxylic acid high performance water reducing agent.

Background

At present, the application of the stone saw mud is also explored a lot, on one hand, the stone saw mud is used as a raw material to produce ash bricks, aerated concrete building blocks, ceramics and the like, but the product market demand is less, and the consumption of the saw mud cannot meet the treatment requirement. On the other hand, dry powder preparation is adopted, the saw mud is dried and ground, and because the water content in the saw mud can reach more than 40 percent at most and the saw mud contains impurities such as fine sand, stone, plastic films and the like, the energy consumption is higher and the economic effect is not obvious when the drying and grinding process is adopted.

The premixed concrete is the material with the largest dosage in the building material industry, and the existing admixture such as fly ash is in short supply, and the natural fine sand is also in short supply. The saw mud is applied to the concrete, the current situation of insufficient supply of the fly ash and fine sand resources can be relieved, the saw mud can be effectively consumed and utilized, and the saw mud has good economic and social benefits.

Disclosure of Invention

The invention aims to provide a method for producing ready-mixed concrete by using stone saw mud, which is suitable for producing concrete with various strength grades for building and municipal engineering. The method for producing the premixed concrete by using the treated stone saw mud has the characteristics of low production cost, large use amount, environmental protection and the like.

The method is realized by the following technical scheme:

a method for producing ready-mixed concrete by using stone sawn mud comprises the following steps:

after the saw mud is pretreated, saw mud particles with the water content of 20-35%, the methylene blue value less than 1.0, the sand content of 15-25% and the dust content of 40-65% are selected, the saw mud particles are used for replacing coal ash and fine sand, part or all of the coal ash is replaced in the mixture ratio, and the rest of the saw mud particles are used for replacing part of sand, so that the content of fine particles below 0.08mm in the sand is supplemented, and the gradation of the sand is improved. The proportion of the saw mud is set according to the principle that the volume weight of the saw mud before and after replacement is not changed.

The methylene blue value of the saw mud particles does not exceed 1.0, and the test standards are GB 35164 and GB/T14684. Methylene blue value is an important index for reflecting the adsorption performance of artificial sand or limestone powder, the methylene blue value is not more than 1.0, and particles below 0.08mm in the saw mud belong to ultrafine powder, so that the workability of concrete can be improved and the compactness of the concrete can be increased.

Further, the pretreatment step comprises the step of screening the saw mud to remove impurities, and the treated saw mud is scattered and rolled to obtain saw mud particles with the looseness of 2.0-3.0.

The calculation formula of the looseness is as follows:

wherein K is the loosening coefficient of the sawn mud;

V₂-the bulk of the sawn mud after breaking up and rolling;

V₁the loose volume of the saw mud before breaking up and rolling.

The common saw mud contains water, and has different sand content, powder content and the like, so that the common saw mud cannot be fully mixed with gel materials and the like to prepare concrete under certain conditions, concrete cracking and the like can occur, and the strength of the concrete is influenced.

The looseness is mainly used for evaluating the dispersion condition of the saw mud particles, and the quality defect can be caused in concrete due to the fact that the looseness is too small and the saw mud particles cannot be dispersed; the excessive looseness is advantageous in the strength and workability of concrete, but there is a problem that the productivity is lowered. Therefore, the selected saw mud particles with proper looseness can be better mixed with gel materials and additives, the solidification effect is better, the strength of concrete is higher, and the production efficiency is not influenced.

According to the saw mud looseness in a proper range, specific water content, sand content, powder content and methylene blue numerical values are combined, the specific available saw mud is determined, resources can be better recycled, the looseness can be realized through processes of scattering, rolling and the like, the operation is simple, and the cost is low.

Further, the maximum particle size of the selected saw mud particles is less than 15 mm.

Further, the cementing material, the sand, the saw mud particles, the broken stone, the water and the admixture are added and stirred according to the raw material proportion to obtain the premixed concrete, wherein the raw material proportion is as follows:

300 portions of cementing material

750 portions of sand and 900 portions of

100 portions of sawn mud particles

950 portions of gravel and 1100 portions of sand

160 portions of water

5-15 parts of a polycarboxylic acid water reducing agent.

Further, the gel material comprises ordinary portland cement, slag micropowder and fly ash.

Further, the strength grade of the ordinary portland cement is not lower than PO 42.5; the type of the slag micro powder is not lower than S75.

Further, the fly ash is above II-grade fly ash.

Furthermore, the sand is mixed medium sand, the fineness modulus is 2.5-2.7, and the methylene blue value is less than 1.5. The mixed sand is prepared by mixing the washing machine-made sand and natural fine sand in proportion, and when the methylene blue value is more than 1.5, clay substances in the stone powder bring adverse effects on the working properties of concrete, and the strength and the durability are influenced.

Furthermore, the particle size of the crushed stone is 5-31.5 mm.

Further, the water reducing agent is a polycarboxylic acid high-performance water reducing agent.

Compared with the prior art, the invention has the following advantages:

1. the adopted saw mud is stored in a storage yard and only needs to be subjected to screening and impurity removal pretreatment;

2. selecting saw mud particles with water content, methylene blue numerical value, sand content and powder content within a specific range, completely or partially replacing fly ash, and replacing partial fine sand with other saw mud particles, so as to supplement the content of the sand particles with the particle size of less than 0.08mm in the raw materials, improve the gradation of the sand, be used for the production of premixed concrete, and realize the change of waste of saw mud into valuable;

3. the saw mud can be used in a large amount, the saw mud consumption is high, the energy consumption is low, the situation that the saw mud is stacked in a large amount is improved, and resources are effectively utilized.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

The invention selects the saw mud stored in a storage yard, obtains saw mud particles with the maximum particle size not more than 15mm after the processes of screening, impurity removal, scattering and rolling, and is directly used for the production of premixed concrete. According to the water content, the sand content and the powder content of the saw mud particles, on one hand, part or all of coal ash can be replaced, on the other hand, part of fine sand is replaced, the content of particles with the particle size of less than 0.08mm in the sand is increased, the gradation of the sand is improved, and the compactness of the concrete is increased. The concrete prepared by using the saw mud to replace part of coal ash has good workability and mechanical property superior to that of standard concrete.

Example 1

The original formula is as follows: 200 parts of ordinary portland cement, 90 parts of slag micro powder, 50 parts of fly ash, 823 parts of sand, 0 part of sawn mud particles, 1020 parts of crushed stone, 170 parts of water and 7 parts of a polycarboxylic acid water reducing agent; wherein the strength grade of the ordinary portland cement is PO 42.5, the type of the slag micro powder is S95, the fly ash adopts II-grade fly ash, the sand is mixed medium sand consisting of washing machine-made sand and river sand, the fineness modulus is 2.5-2.9, and the particle size of the crushed stone is 5-31.5 mm.

100 parts of sawn mud particles are used to replace 30 kg of fly ash, 60 kg of sand and 10 kg of water.

The substituted raw materials are as follows: 200 parts of ordinary portland cement, 90 parts of slag micro powder, 20 parts of fly ash, 763 parts of sand, 100 parts of saw mud, 1020 parts of crushed stone, 160 parts of water and 7 parts of polycarboxylic acid water reducing agent; wherein the strength grade of the ordinary portland cement is PO 42.5, the type of the slag micro powder is S95, the fly ash adopts II-grade fly ash, the sand is mixed medium sand consisting of washing machine-made sand and river sand, the fineness modulus is 2.5-2.9, the methylene blue value is less than 1.5, and the particle size of the crushed stone is 5-31.5 mm.

(1) The method comprises the following steps of screening and removing impurities from the yard saw mud, and mainly screening impurities such as large stones, plastics and the like in the saw mud. And piling the sieved saw mud for later use.

(2) And then, scattering and rolling the saw mud to obtain saw mud particles with the looseness of 2.0, wherein the maximum particle size is less than 15 mm.

The calculation formula of the looseness is as follows:

wherein K is the loosening coefficient of the sawn mud;

V₂-the bulk of the sawn mud after breaking up and rolling;

V₁the loose volume of the saw mud before breaking up and rolling.

The common saw mud contains water, and has different sand content, powder content and the like, so that the common saw mud cannot be fully mixed with gel materials and the like to prepare concrete under certain conditions, and concrete cracking and the like can occur. The selected saw mud particles with proper looseness can be better mixed with gel materials and additives, and the solidification effect is better. The method has the advantages that the specific available saw mud is determined according to the limitation on the saw mud looseness, the specific water content, the specific sand content, the specific dust content and the specific methylene blue value are combined, the resource can be better recycled, the looseness can be realized through the technologies of scattering, rolling and the like, the operation is simple, and the cost is low.

(3) Selecting saw mud particles with the water content of 20 percent, the sand content of 25 percent, the powder content of 55 percent and the methylene blue value of 1.0.

(4) And adding the cementing material, the sand, the saw mud particles, the broken stone, the water and the polycarboxylic acid water reducing agent according to the substituted raw material proportion, and stirring to obtain the premixed concrete. In order to ensure the dispersion uniformity of the saw mud, the stirring time is preferably prolonged by 5-10 s.

The test standards of the water content, the sand content and the powder content refer to GB/T14684;

the test standard for methylene blue values is referred to GB 35164.

Example 2

The original formula is as follows: 250 parts of ordinary portland cement, 120 parts of slag micro powder, 50 parts of fly ash, 762 parts of sand, 0 part of sawn mud particles, 1020 parts of crushed stone, 170 parts of water and 8.5 parts of a polycarboxylic acid water reducing agent; wherein the strength grade of the ordinary portland cement is PO 42.5, the type of the slag micro powder is S95, the fly ash adopts II-grade fly ash, and the particle size of the crushed stone is 5-31.5 mm. The water reducing agent is a polycarboxylic acid high-performance water reducing agent.

100 parts of sawn mud particles are used to replace 50 kg of fly ash, 45 kg of sand and 5 kg of water.

The substituted raw materials are as follows: 250 parts of ordinary portland cement, 120 parts of slag micro powder, 707 parts of sand, 100 parts of sawn mud particles, 1020 parts of broken stone, 165 parts of water and 8.5 parts of a polycarboxylic acid water reducing agent; wherein the strength grade of the ordinary portland cement is PO 42.5, the type of the slag micro powder is S95, the fly ash adopts II-grade fly ash, the sand is mixed medium sand consisting of washing machine-made sand and river sand, the fineness modulus is 2.5-2.9, and the particle size of the crushed stone is 5-31.5 mm.

(1) The method comprises the following steps of screening and removing impurities from the yard saw mud, and mainly screening impurities such as large stones, plastics and the like in the saw mud. And piling the sieved saw mud for later use.

(2) And then, scattering and rolling the saw mud to obtain saw mud particles with the looseness of 3.0, wherein the maximum particle size is less than 15 mm.

The calculation formula of the looseness is as follows:

wherein K is the loosening coefficient of the sawn mud;

V₂-the bulk of the sawn mud after breaking up and rolling;

V₁the loose volume of the saw mud before breaking up and rolling.

The common saw mud contains water, and has different sand content, powder content and the like, so that the common saw mud cannot be fully mixed with gel materials and the like to prepare concrete under certain conditions, and concrete cracking and the like can occur. The selected saw mud particles with proper looseness can be better mixed with gel materials and additives, and the solidification effect is better. The method has the advantages that the specific available saw mud is determined according to the limitation on the saw mud looseness, the specific water content, the specific sand content, the specific dust content and the specific methylene blue value are combined, the resource can be better recycled, the looseness can be realized through the technologies of scattering, rolling and the like, the operation is simple, and the cost is low.

(3) Selecting saw mud particles with the water content of 15 percent, the sand content of 20 percent, the dust content of 65 percent and the methylene blue value of 1.0.

(4) And adding the cementing material, the sand, the saw mud particles, the broken stone, the water and the polycarboxylic acid water reducing agent according to the substituted raw material proportion, and stirring to obtain the premixed concrete. In order to ensure the dispersion uniformity of the saw mud, the stirring time is preferably prolonged by 5-10 s.

The test standards of the water content, the sand content and the powder content refer to GB/T14684;

the test standard for methylene blue values is referred to GB 35164.

Comparative example 1

Comparative example 1 differs from example 1 in that the formulation of comparative example 1 is a normal concrete formulation, and no saw mud is used to replace fly ash, sand and water.

The raw material ratio is as follows: 200 parts of ordinary portland cement, 90 parts of slag micro powder, 50 parts of fly ash, 823 parts of sand, 0 part of sawn mud particles, 1020 parts of crushed stone, 170 parts of water and 7 parts of a polycarboxylic acid water reducing agent; wherein the strength grade of the ordinary portland cement is PO 42.5, the type of the slag micro powder is S95, the fly ash adopts II-grade fly ash, the sand is mixed medium sand consisting of washing machine-made sand and river sand, the fineness modulus is 2.5-2.9, and the particle size of the crushed stone is 5-31.5 mm.

And adding the cementing material, the sand, the saw mud particles, the broken stone, the water and the polycarboxylic acid water reducing agent according to the substituted raw material proportion, and stirring to obtain the premixed concrete. In order to ensure the dispersion uniformity of the saw mud, the stirring time is preferably prolonged by 5-10 s.

Comparative example 2

Comparative example 2 differs from example 2 in that the formulation of comparative example 2 is a normal concrete formulation, and no saw mud is used to replace fly ash, sand and water.

The raw material ratio is as follows: 250 parts of ordinary portland cement, 120 parts of slag micro powder, 50 parts of fly ash, 762 parts of sand, 0 part of sawn mud particles, 1020 parts of crushed stone, 170 parts of water and 8.5 parts of a polycarboxylic acid water reducing agent; wherein the strength grade of the ordinary portland cement is PO 42.5, the type of the slag micro powder is S95, the fly ash adopts II-grade fly ash, and the particle size of the crushed stone is 5-31.5 mm. The water reducing agent is a polycarboxylic acid high-performance water reducing agent.

And adding the cementing material, the sand, the saw mud particles, the broken stone, the water and the polycarboxylic acid water reducing agent according to the substituted raw material proportion, and stirring to obtain the premixed concrete. In order to ensure the dispersion uniformity of the saw mud, the stirring time is preferably prolonged by 5-10 s.

Comparative example 3

Comparative example 3 differs from example 1 in that: comparative example 3 saw mud had a looseness of 1.0. The rest is the same as in example 1.

Comparative example 4

Comparative example 4 differs from example 2 in that: comparative example 4 had a saw mud looseness of 4.0. The rest is the same as in example 2.

TABLE 1 raw material ratio of examples 1-2 and comparative examples 1-4

The examples 1-2 and comparative examples 1-4 were subjected to performance tests, and the test results are shown in Table 2.

Slump was tested according to GB/T50080 related regulations;

the extension degree is tested according to GB/T50080 related regulations;

the homogeneity is tested according to the relevant regulation of the homogeneity of the concrete stirred uniformly in the same disc of GB 50164 concrete quality control Standard 6.4.4;

the compressive strength is tested according to GB/T50081 relevant regulations;

the shrinkage rate is referred to GB/T50082 Standard test method for Long-term Performance and durability of ordinary concrete 8 related specified tests of shrinkage test.

TABLE 2 test results

As can be seen from comparison between examples 1-2 and comparative examples 1-2, the use of the saw mud particles with the water content of 20-35%, the methylene blue value less than 1.0, the sand content of 15-25% and the powder content of 40-65% can effectively enhance the compressive strength of concrete, and the saw mud replaces fly ash and sand, so that the reutilization of waste solid resources is realized, the production cost is low, and the environment is protected.

Comparative example 3 is inferior to example 1 in compressive strength because the looseness affects the compressive strength of concrete due to too small looseness as compared with example 1, and comparative example 4 is too large in looseness as compared with example 2, and although a certain degree of enhancement in compressive strength can be obtained, the production efficiency in concrete production is seriously affected.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, but rather as the subject matter of the invention is to be construed in all aspects and as broadly as possible, and all changes, equivalents and modifications that fall within the true spirit and scope of the invention are therefore intended to be embraced therein.