Preparation and application of broken pebble concrete

Abstract

The invention provides preparation and application of crushed pebble concrete. The preparation comprises the following steps: controlling the quality of premixed concrete raw materials, screening coarse aggregate crushed pebbles, and proportioning according to a ratio and a process after screening. The crushed pebble concrete is prepared from the following raw materials in parts by mass: 550-650 Kg / m < 3 > of a cementing material, 140-160 Kg / m < 3 > of water, 130-350 Kg / m < 3 > of an additive and 800-1200 Kg / m < 3 > of crushed pebbles, and in the manufacturing process of the crushed pebble concrete, the crushed pebbles, cement, sand, water and other materials need to be fully stirred by using a concrete stirrer, air is removed, and the compactness of the concrete is ensured. And then, pouring the concrete into a prepared mold or a construction site, and carrying out the steps of pouring, compacting, curing and the like. And finally, after the concrete is fully dried, the mold can be taken out, and the crushed pebble concrete is used for engineering construction of landscape architecture, sidewalks, roadbeds and the like.

Description

Technical Field

[0001] The invention relates to the technical field of concrete, and in particular to the preparation and application of crushed pebble concrete. Background Art

[0002] Concrete is generally made of cementitious materials, granular aggregates (also called aggregates), water, and admixtures and admixtures added when necessary, in a certain proportion, and is uniformly mixed, compacted, cured and hardened to form an artificial stone material, referred to as concrete, which is widely used in various civil engineering projects such as construction, roads, and bridges. With the continuous improvement of technology in the concrete industry in recent years, the supply of sand and gravel has become increasingly tight. Traditional high-strength concrete has a small amount of gel material and a large amount of cement, which requires higher additives in aggregates. Aggregates are granular materials that play a skeleton and filling role in concrete and mortar. Aggregates generally use natural sand, such as river sand, sea sand and valley sand. When natural sand is lacking, artificial sand ground from hard rocks can also be used; coarse aggregates commonly used in lightweight aggregate concrete include natural porous rocks such as pumice, and artificial porous aggregates such as ceramsite and expanded slag. Too large a particle size and a large content of needle-like particles will directly affect the strength of concrete and the performance of concrete mixtures. Generally, limestone crushed stones with smaller particle sizes are used, and the mining of limestone causes resource consumption and environmental pollution, and the cost is very high. Therefore, a new type of crushed pebble material is urgently needed as the preparation material of concrete. Summary of the invention

[0003] The purpose of the present invention is to provide a preparation and application of crushed pebble concrete, aiming to solve the problems of resource consumption and environmental pollution of aggregate used in preparing concrete in the above-mentioned prior art.

[0004] The technical solution of the present invention is: in order to solve the above technical problems, the present invention provides a preparation and application of crushed pebble concrete, controls the quality of raw materials for ready-mixed concrete, screens coarse aggregate crushed pebbles, and mixes ingredients according to proportions and processes after screening. According to mass fractions, the following raw materials are included:

[0005] The components and contents of each group are as follows:

[0006] Cementitious material 550-650Kg / m 3 ;

[0007] Water 140-160Kg / m 3 ;

[0008] Admixture 130-350Kg / m 3 ;

[0009] Crushed Pebbles 800-1200Kg / m 3 ;

[0010] The cementitious materials include limestone, clay and ore, which are powdered substances (ore powder) and cement made by grinding, mixing, calcining and other processes;

[0011] Among them, limestone is 6%-8%, mineral powder is 6%-18%;

[0012] The admixture accounts for 2.2-4.5% of the total amount of the cementitious material;

[0013] Accelerators such as calcium formate, silica fume, and calcium chloride can be added to the admixtures; 1.2%-1.8%;

[0014] Retarder: gypsum, starch acid salt (the retarder content can reach up to 0.06%);

[0015] Water reducing agent: plasticizer, superplasticizer, etc. 1.6%-4.5%;

[0016] Volcanic ash admixture: natural volcanic ash materials include clay, shale, volcanic tuff, pumice, etc., artificial volcanic ash includes fly ash, silica ash, blast furnace slag, rice husk ash, etc. 2.5%-3.8%;

[0017] The crushed pebble particles are preferably round or oval particles with a diameter of ≥5 mm;

[0018] Crushed stone particles: particles with a diameter of ≥1mm and <5mm;

[0019] Needle-shaped particles: particles with a length ≥ 3 times the width;

[0020] Flaky particles: particles with a width ≥ 3 times the thickness;

[0021] The content of crushed pebbles is ≤25%, the content of crushed stones is ≤45%, the content of needle-like particles is ≤5%, and the apparent density is 2730kg / m 3 ;

[0022] Preferably, the river sand, medium sand in zone II, fineness modulus 2.7, mud content 2.0%, mud block content 0.5% fine stone: continuous grading 5-16mm, mud content 1.0%, crushing value index 9%. 200kg fly ash ceramsite: particle size 5-15mm, density 800kg / m3;

[0023] Preferably, the fly ash has a sieve residue of 0.045 mm or less than 12%. Water requirement ratio: water requirement ratio is less than or equal to 95%. Loss on ignition: loss on ignition is less than or equal to 5%. Water content: water content is less than or equal to 1%; Preferably, the specific surface area: 400-450 m2 / kg;

[0024] Activity index: 7d, 75% to 85%; 28d, 95% to 105%;

[0025] Density: 2.8~2.9g / cm3;

[0026] Preferably, the cement is P.O42.5 cement, and the cement content is 380-460Kg / m 3 .

[0027] The beneficial effects of the present invention are as follows: compared with the prior art, the present invention adopts crushed pebbles as coarse aggregate added to concrete, which has better granularity and higher strength, so the mixed concrete has high strength and good compressive resistance. The crushed pebbles are green and environmentally friendly building materials, which can be used to dredge waste in waterways, reduce concrete costs, thereby saving resources and protecting the environment. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The invention provides a preparation and application of crushed pebble concrete, wherein the coarse aggregate crushed pebbles are screened, and the ingredients are mixed according to the proportion and process after the screening. The raw materials are as follows, calculated by weight:

[0030] The components and contents of each group are as follows:

[0031] Cementitious material 550-650Kg / m 3 ;

[0032] Water 140-160Kg / m 3 ;

[0033] Admixture 130-350Kg / m 3 ;

[0034] Crushed Pebbles 800-1200Kg / m 3 ;

[0035] The cementitious materials include limestone, clay and ore, which are powdered substances (ore powder) and cement made by grinding, mixing, calcining and other processes;

[0036] Among them, limestone is 6%-8%, mineral powder is 6%-18%;

[0037] The admixture accounts for 2.2-4.5% of the total amount of the cementitious material;

[0038] Accelerators such as calcium formate, silica fume, and calcium chloride can be added to the admixtures; 1.2%-1.8%;

[0039] Retarder: gypsum, starch acid salt (the retarder content can reach up to 0.06%);

[0040] Water reducing agent: plasticizer, superplasticizer, etc. 1.6%-4.5%;

[0041] Volcanic ash admixture: natural volcanic ash materials include clay, shale, volcanic tuff, pumice, etc., artificial volcanic ash includes fly ash, silica ash, blast furnace slag, rice husk ash, etc. 2.5%-3.8%;

[0042] The crushed pebble particles are preferably round or oval particles with a diameter of ≥5 mm;

[0043] Crushed stone particles: particles with a diameter of ≥1mm and <5mm;

[0044] Needle-shaped particles: particles with a length ≥ 3 times the width;

[0045] Flaky particles: particles with a width ≥ 3 times the thickness;

[0046] The content of crushed pebbles is ≤25%, the content of crushed stones is ≤45%, the content of needle-like particles is ≤5%, and the apparent density is 2730kg / m 3 ;

[0047] Preferably, the river sand, medium sand in zone II, fineness modulus 2.7, mud content 2.0%, mud block content 0.5% fine stone: continuous grading 5-16mm, mud content 1.0%, crushing value index 9%. 200kg fly ash ceramsite: particle size 5-15mm, density 800kg / m3;

[0048] Preferably, the fly ash has a sieve residue of 0.045 mm or less than 12%. Water requirement ratio: water requirement ratio is less than or equal to 95%. Loss on ignition: loss on ignition is less than or equal to 5%. Water content: water content is less than or equal to 1%; Preferably, the specific surface area: 400-450 m2 / kg;

[0049] Activity index: 7d, 75% to 85%; 28d, 95% to 105%;

[0050] Density: 2.8~2.9g / cm3;

[0051] Preferably, the cement is P.O42.5 cement, and the cement content is 380-460Kg / m 3 .

[0052] Example 1: Conventional pebble concrete mix ratio

[0053] Cement: 427kg; Sand: 701kg; Crushed gravel: 1288kg.

[0054] Example 2, high performance pebble concrete mix ratio: cement: 427kg; sand: 886kg; ultrafine mineral powder: 88kg; crushed pebbles: 1208kg.

[0055] This mix ratio adds ultra-fine mineral powder to improve the strength and durability of concrete.

[0056] Example 3, mix ratio of crack-resistant pebble concrete: cement: 457kg; sand: 665kg; crushed pebbles: 1185kg; polypropylene fiber: 1.2kg.

[0057] Polypropylene fibers are added to this mix ratio to improve the crack resistance of concrete.

[0058] The cement is a cementitious material for crushed pebble concrete, and its usage generally accounts for 10% to 15% of the total mix ratio. In terms of the selection of cement, cement with good quality and high strength should be selected.

[0059] The diameter of the crushed pebble aggregate is relatively large, generally more than 20 mm. Aggregate is the main component of crushed pebble concrete, and its usage accounts for more than 60% of the total mix ratio. In the selection of pebbles, pebbles with uniform texture and dense structure should be selected according to the needs of the project to ensure the homogeneity and density of the concrete. When selecting pebbles, it is best to select stones with high flatness so that the air can be better removed after the concrete is mixed. In addition, the pebbles should be dry, clean, and free of oil stains and other attachments.

[0060] Sand is the screening material for pebble concrete, and its usage accounts for more than 25% of the total mix ratio. In terms of sand selection, sand with moderate particle size, dryness, and no soil and impurities should be selected to ensure the homogeneity of concrete.

[0061] In the production process of crushed pebble concrete, it is necessary to use a concrete mixer to fully mix materials such as pebbles, cement, sand and water, remove air and ensure the density of the concrete. Then, pour the concrete into the pre-prepared mold or construction site for pouring, compacting and curing. Finally, when the concrete is fully dry, the mold can be removed and the crushed pebble concrete can be used for landscaping, sidewalks, roadbeds and other engineering construction.

[0062] When mixing concrete, pay attention to the order of adding materials. Add cement first, then sand and pebbles, and finally water. The mixing time should be sufficient to evenly distribute the various materials.

[0063] The pouring of concrete is carried out gradually and compacted with professional tools to ensure the density and strength of the concrete.

[0064] After pouring concrete, it must be cured to ensure that the concrete gradually solidifies and achieves the best use effect.

[0065] The filling properties between aggregates of crushed pebble concrete are good, which can reduce the use of cement and reduce costs. Crushed pebble concrete has high strength, especially its compressive strength and durability, which makes it widely used in projects with high durability requirements.

[0066] Select according to the needs of the project. Crushed pebble concrete is widely used in foundation engineering, road construction and other fields.

[0067] Crushed pebble concrete is a building material commonly used in garden, sidewalk, roadbed and other construction projects. It is durable, waterproof and anti-corrosive.

[0068] In summary, the present invention has the advantages of energy saving, environmental protection and high strength. The river pebbles that are crushed and shaped to eliminate particle size defects are used as coarse aggregates. The pebbles after crushing and shaping have a small content of needle-like particles, a good particle shape, and a crushing value of less than 10%, which is conducive to the reasonable accumulation of aggregates and the reasonable distribution of stress in concrete, so that the overall material particle grading distribution in high-strength concrete tends to be more reasonable, which is conducive to improving the working performance of concrete mixtures and the strength of concrete, thereby achieving the purpose of saving resources and protecting the environment.

[0069] In the above description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed above.

Claims

1. Preparation and application of crushed pebble concrete, characterized by: Control the quality of raw materials for ready-mixed concrete, screen the coarse aggregate and crushed pebbles, and mix them according to the proportion and process. According to the mass percentage, the following raw materials are included: cementitious material 550-650Kg / m 3 , water 140-160Kg / m 3 , admixture 130-350Kg / m 3 , crushed pebbles 800-1200Kg / m 3 .

2. The preparation and application of crushed pebble concrete according to claim 1 is characterized in that: The cementitious material includes powdered material (ore powder) and cement made by grinding, mixing, calcining and other processes of limestone, clay and ore.

3. The preparation and application of crushed pebble concrete according to claim 1 is characterized in that: Limestone 6%-8%, mineral powder 6%-18%.

4. The preparation and application of crushed pebble concrete according to claim 1 is characterized in that: The admixture accounts for 2.2-4.5% of the total amount of the cementitious material.

5. The preparation and application of crushed pebble concrete according to claim 1 is characterized by: Accelerators such as calcium formate, silica fume and calcium chloride can be added to the admixtures; 1.2%-1.8%.

6. The preparation and application of crushed pebble concrete according to claim 1, characterized in that: Plasticizers, superplasticizers, etc. 1.6%-4.5%.

7. The preparation and application of crushed pebble concrete according to claim 1, characterized in that: Natural volcanic ash materials include clay, shale, volcanic tuff, pumice, etc., and artificial volcanic ash includes fly ash, silica ash, blast furnace slag, rice husk ash, etc. 2.5%-3.8%.

8. The preparation and application of crushed pebble concrete according to claim 1, characterized in that: Crushed pebble particles: round or oval particles with a diameter ≥5mm, crushed stone particles: particles with a diameter ≥1mm, <5mm, needle-shaped particles: particles with a length ≥3 times the width, flake-shaped particles: particles with a width ≥3 times the thickness.

9. The preparation and application of crushed pebble concrete according to claim 1, characterized in that: The content of crushed pebbles is ≤25%, the content of crushed stones is ≤45%, the content of needle-like particles is ≤5%, and the apparent density is 2730kg / m 3 .

10. The preparation and application of crushed pebble concrete according to claim 1, characterized in that: The cement used is P.O42.5 cement, and the cement content is 380-460Kg / m 3 .