The use of artificial gravel aggregates in water conservancy projects to replace natural gravel aggregates has been widely promoted and applied, which can fundamentally solve the difficulty of building gravel aggregate shortages. Taking the actual project as an example, the article first analyzed the main measures for controlling the production quality of gravel aggregate, and then analyzed the strategy for controlling the cost of concrete gravel aggregate to ensure the quality of gravel aggregate and control Its production cost promotes the growth of the enterprise's economic benefits, with a view to providing a reference for similar projects.
The two main components of concrete are stone and sand, which are collectively referred to as aggregate. In concrete, aggregate has a very important role. Natural sand and gravel materials in nature are non-renewable resources and are very limited. In order to meet the needs of construction, it is necessary to use artificially produced aggregates to replace natural sand and gravel materials. The article mainly discusses and analyzes how to effectively control its quality and production cost in the production process of aggregates.
1. Feed yard overview
Taking the construction of water conservancy projects as an example, the stockyard is located close to the dam of a water conservancy project, and is located on the class I terrace on the right bank of the m
ountain exit downstream. It is 2.2km away from the dam site. The grain size of the wool in this stockyard is good and the particle size is relatively small. Continuous, suitable for concrete aggregate. In the lower part, there are medium-coarse sand and conglomerate formed by alluvial rock layer, and the thickness of useful material is 2m~3m, and the gravel layer is below the medium-coarse sand layer. The value is 3.2m. The local gravel is exposed on the surface, and the thickness of the gravel layer is 1m~2m. The covering layer of the stockyard is thin, and the site is relatively open and flat, which is conducive to large-scale mechanized mining operations.
2. Main measures for quality control
2.1 Control the source quality.
Before mining wool, it is necessary to remove the covering layer on the top of the stockyard to ensure that there is no grass roots, covering soil and other substances on the surface of the mining layer. When cleaning the cover layer, try to ensure that it is completed at one time, and it is necessary to leave a certain width of the protective zone to avoid the vibration generated during the mining of the wool to make the cover soil at the boundary position slip and fall into the wool again. In view of the different depths of mudstone burial and the high groundwater level, it is necessary to excavate the drainage channel before mining to reduce the groundwater level; when mining, the mining should be carried out in the order from low to high. For the cover layer, ensure the stripping of the boundary The width is more than 0.8m above the planned mining area. The depth of mining must be strictly controlled to ensure that the thickness of the reserved layer is> 0.2m.
2.2 Control the particle size.
The production of machine-made aggregates is divided into links such as crushing, sieving and sand making, among which the sieving is the most critical link to control the particle size of aggregates. The quality control of gravel aggregates is mainly based on the particle size and grading requirements of concrete aggregates, using advanced and mature crushing equipment and vibrating screens and screens with standard apertures to ensure that the produced concrete aggregates meet the grading quality standards determined by the specifications and Regulations. The filter screen for screening coarse aggregate can be a square mesh screen made of polyurethane material. The size of the mesh is divided into 5mm, 10mm, 20mm, 40mm, 80mm and other specifications according to the aggregate gradation. In addition to any inspection during the production process, every interval One month or every 20,000-30,000 cubic meters of production needs to be repaired and replaced once to ensure the integrity of the production equipment; the commonly used grading of coarse aggregate in water conservancy and hydropower projects is divided into small stones (5~20mm), medium stones (20~40mm), dashi (40~80mm); Multi-layer circular vibrating screens are commonly used in hydropower projects for screening and classification. Because of the small amount of dashi used in small projects, drum screens can be used for individual production as needed. It is necessary to carry out regular inspection and replacement of the screen of each sieve, establish a record of maintenance and replacement, and only through effective management methods and scientific work processes can the effective control of the particle size of the gravel aggregate.
2.3 Control mud content.
Strictly control the inclination angle of the screen and the amount of raw materials that need to be screened, and equip it with a reliable and stable flushing system. This flushing system requires a main water pipe with a water supply capacity of 100-120 cubic meters per hour and a diameter of 100mm; the diameter of the water pipe used on the screening machine is 60mm, and the spacing of the water supply pipe is controlled between 25-35mm; the water pipe The diameter of the water supply branch pipe is 5~8mm, the layout of the water spray holes should be uniform, and the water pressure should be adjusted to the appropriate pressure during flushing; the water sprayed by the adjacent water spray holes must be crossed to ensure that the sprayed water can be uniform Cover the entire screen, otherwise it is necessary to make timely adjustments to the number, spacing and direction of water spray holes.
2.4 Protection of finished aggregates.
When the gravel aggregates screened from the screening workshop are transported to the finished material yard for storage by the belt conveyor, they should be equipped with partition walls and stacked in sections to prevent mixing in the yard. Product labels shall be set at the place where the finished materials are stacked, and the spacing of aggregates naturally stacked without partitions shall be> 3m, and shall be neat and orderly. A blind ditch drainage system is built in the finished product yard to ensure that the washed aggregate can be quickly dehydrated after entering the pile to meet the moisture content requirements for concrete production.
3. Strategies to control cost
3.1 A reasonable and scientific assessment from an economic perspective.
The cost control of the gravel aggregate used in concrete should be carried out after a reasonable and scientific evaluation from an economic perspective. This requires relevant professionals to accurately screen out the basic parameters required for the control of the production cost of aggregates based on actual statistical data, and then combine the scientific calculation method to calculate the need to be used in the production of concrete According to the actual situation in the industry and the market, the quantity and aggregate of sand and gravel can be used to estimate the general scope and level of construction cost. The current market price of the aggregates used in the production of concrete and its unilateral cost must be paid attention to and accurate in the entire calculation process. It is also necessary to investigate and analyze the prices of machines and equipment for mining gravel aggregates, so as to better effectively control the labor expenditures in the entire process of concrete production from gravel aggregate mining to stacking and processing. At the same time, it is not only necessary to calculate the unit price of sand and gravel, the unit price of sieving, washing, crushing, and transportation of gravel aggregate wool, the unit price of cleaning the covering of sand and gravel, the scrap of finished aggregate and the unit price of transportation, Also review and review all calculated data.
3.2 Improve the technology for producing concrete aggregates.
Due to different lithology, strength, hardness and other indicators of raw materials, the production process, production process and production process involved in the production of concrete aggregates are flexible and changeable, and different production process processes need to be selected according to the actual situation And equipment. Unexpected failures and problems may occur in every production link. This requires strict technical requirements for production and strives for excellence. Of course, the technology used in the production process must also meet the standards in the industry. Production enterprises abandon backward production concepts and introduce and put in advanced production equipment in time, so as to promote a more orderly and efficient production process. Moreover, for the critical production process of screening gravel aggregates, special attention should be paid to the production technology used. It is also necessary to allow skilled and experienced workers to operate as much as possible to monitor the operation of the equipment in real time. Try to avoid problems with details. In addition, it is necessary to check the quality of the various production equipment in use, and the production equipment should not be allowed to have substandard performance and unqualified quality, so as to ensure the strength requirements of the concrete gravel aggregate to the greatest extent, so as to better To achieve the purpose of controlling cost and saving costs.
3.3 Maximize the utilization rate of production materials.
The material that has the greatest impact on the cost of the entire production process is the production material. Therefore, the utilization rate of the production material can be maximized to control the production cost, and the waste of sand and aggregate can be minimized. It is particularly important for the stacking and transportation of finished products.
In summary, for the production of natural gravel aggregates, the production process of machine-made gravel aggregates is cumbersome, and the technical and professional requirements are very high. If there are any omissions in the production process, it will affect the finished aggregates. The impact of quality will also cause the cost of the entire production to skyrocket. Therefore, it is necessary to strictly control the production process, pay attention to the management of the production process, strictly monitor the entire production process, and supervise the cost of each production link, so as to promote the efficient and orderly development of concrete sand and aggregate production.
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