Cement can be said to be a common item in our home decoration. It is widely used in walls and floors, accounting for a large proportion of decoration materials. Therefore, the choice of cement is very important. Choosing a good cement can not only make the visual experience better, but also make our life more comfortable and prevent harmful substances in the cement from harming our health. This article will introduce you to some cement purchasing tips for your reference when choosing to purchase.
Part1: Understand the basic knowledge of cement from scratch
Cement is often mixed with sand in different ratios to form cement mortar, which is used to enhance the adsorption capacity of ceramic tiles, etc. Among them, sand is more familiar to us and can be accessed at the seaside, riverside, etc. We know relatively little about cement. Let’s get to know cement together.
1. What is cement?
How to make cement: Cement uses limestone and clay as the main raw materials. It is crushed, batched, and ground into raw meal, and then fed Clinker is calcined in a cement kiln, and then the clinker is ground with an appropriate amount of gypsum (sometimes mixed with mixed materials or additives).
Basic characteristics of cement: Cement is a powdery hydraulic inorganic cementitious material. Add water and stir to form a slurry, which can harden in the air or better in water, and can firmly bind sand, stone and other materials together.
2. Cement grade suitable for home decoration: No. 325
Currently, the cement produced in my country generally has several grades such as 225#, 325#, 425#, 525#, etc. The purpose of producing cement of different grades is to meet the needs of making concrete of different grades. The cement used for home decoration is generally 325, because the decoration cement does not need to withstand too much force and does not require high-grade cement. Furthermore, when driving nails into the wall, 325 cement is softer than high-grade cement. , easier to push in.
3. Calculation of home decoration cement usage
The places where cement is used in home decoration are different, and the ratio of cement to sand is also different. For example, the best ratio of wall tiles is 1:2, and the ratio of floor tiles is 1:3. In addition, bricklayers have different laying techniques, and the amount of cement mortar is also different. Therefore, it is difficult to accurately calculate the amount of cement required. However, the approximate calculation method is: area x paving thickness x cement ratio in cement mortar. When decorating, you can buy less cement first, and then buy more when it is not enough.
4. Commonly used types of cement for home decoration: ordinary Portland cement
Cement can be divided into Portland cement, aluminate cement, and sulfoaluminate cement according to its main components. Salt cement and phosphate cement, etc. The most common cement is Portland cement.
Portland cement: National standards stipulate that any Portland cement clinker mainly composed of calcium silicate is made of less than 5% limestone or granulated blast furnace slag and an appropriate amount of gypsum. Hard cementitious materials, collectively known as Portland cement. Portland cement itself has many categories, and ordinary Portland cement is generally used for home decoration. It may also be necessary to use some decorative white Portland cement.
5. Cement price calculation
Cement is calculated in tons. Because its bulk density tends to be stable and is equivalent to a constant, it is calculated in tons. Different brands of cement have different prices per ton, generally between 300-500 yuan. In addition, transportation costs need to be calculated when purchasing cement.
Part 2: What you need to know about purchasing skills so you don’t have to worry about purchasing high-quality cement
Cement is a product that is used in large quantities in concealed projects. Currently, the phenomenon of shoddy quality cement is relatively common in the market. Many, if you buy fake cement, the quality is not reliable, and it will be difficult to repair if there is a problem. Here are a few inspection steps to teach you how to check the quality of cement when purchasing.
1. Understand the dangers of fake cement
The cement market is relatively chaotic, and you may encounter fake cement if you are not careful. Fake cement is generally produced by small workshops and sold in the building materials market after being put into famous brand cement packaging bags. Fake cement is more harmful. Not only does it often contain radioactive substances exceeding the standard, threatening human health, but what is even more frightening is that because of its poor solidification, it can easily cause problems such as powder and wall peeling, and repairs are very troublesome.
2. Choose real cement with a keen eye
1. Check the appearance of the cement packaging
National standards stipulate: cement variety, label number, factory name and factory name in the cement packaging label Incomplete numbers are considered defective products. You can also look at the binding line of the package and the brand label. There are four words "Green Product" above the paper bag. The sealing edges are round and closed. If there are two single paper edges, it means that the package has been opened. The color of the brand label on the back of the real cement bag is relatively soft, and the word "fixed point" is written in small seal script. This is quite different from the fake cement.
2. Check the cement production date
Real cement bags will have a batch number on the side or back to indicate the production date, because cement is prone to moisture or agglomeration after being stored for a long time. Generally, from the time of leaving the factory to the time of purchase The time will not exceed one week, and the implementation standard should be GB175-2007. Because the fake ones are produced by small workshops, they generally don’t have batch numbers or use expired packaging.
3. Distinguish the color of cement
Observe whether the color is dark gray or dark green. If the color is yellow or white (yellow indicates that the clinker is raw material, white indicates that the slag is mixed with cement). (too much) cement strength is relatively low. Generally speaking, the normal color of cement should be off-white. If the color is too dark or changes, it may be due to excessive other impurities.
4. Weigh the cement
Cement can be packed in bags or in bulk. However, the net weight of each bag of bagged cement is 50kg and shall not be less than 98% of the marked weight. You can randomly select 20 bags, as long as the total weight of cement is not less than 1000kg, it is a qualified weight. Regarding bag weight requirements, these principles must be followed.
5. The feel of kneading cement
The feel of fake cement is not as good as that of real cement. When you twist the fake cement powder with your fingers, you will feel that there is more coarse sand powder and there is no trace of it. There are few coarse and hard particles, and there are moisture and agglomeration phenomena. If it feels a little fine, sandy, or powdery, it indicates that the cement fineness is normal.
Part 3: Ensure the quality of cement, be careful during transportation and storage
After finally purchasing 100% real cement through various methods and channels, many owners breathed a sigh of relief. . In fact, real cement does not guarantee that there will be no problems when used in decoration. To ensure that it is foolproof, there are things that need to be paid attention to from the transportation, storage and use of cement.
1. Precautions for cement transportation
The amount of cement used for home decoration is generally measured in tons. Transportation is a big problem. It not only requires transportation costs, but also if you do not pay attention to moisture-proof and Protection such as waterproofing can easily lead to problems such as hard lumps in the arriving cement.
2. Precautions for cement storage
A warehouse of sufficient capacity that is completely dry, well-ventilated, weatherproof, and moisture-proof should be established in an appropriate location to store cement. The cement stack should be at least The surrounding walls are 200mm, and a channel with a width of not less than 700mm should be left between each stack; bulk cement should be stored in special tanks. During storage, the ground and the inside of the outer wall should be moisture-proof.
3. Precautions for entering the cement site
After the cement enters the site, the delivery person should provide the home improvement project manager with a list of each batch of cement, indicating the name of the manufacturer, cement type and quantity, And the manufacturer's test instructions confirm that the batch of cement has been tested and analyzed and meets the standards and specifications in all aspects. In addition, each batch of cement entering the site should be sampled and inspected according to the test procedures, and the results should be reported to the supervision engineer for approval. Unqualified cement shall not be used.
4. Treatment of moisture-hardened cement
Moisture-hardened cement will reduce or even lose its original strength. Therefore, the specification stipulates that cement that has been out of the factory for more than 3 months should be re-examined and tested. Use according to test results. Cement that has become lumpy or hardened due to moisture must be screened before use. The screened out lumps are generally used for masonry mortar or plastering mortar in secondary projects after being kneaded or ground finely. For cement clumps that pulverize when touched or pinched, the strength level can be appropriately reduced for use.
5. Precautions for the use of cement
Cement should be used as soon as possible after being transported to the construction site. If the cement has deteriorated or cannot be used due to moisture or other reasons, it should be transported away from the construction site. Cement should not be stored for a long time. Cement that is more than three months old must be retested to determine its quality.
Through the above introduction, we have roughly understood some tips for purchasing cement for home decoration.
From this we can see that the choice and purchase of cement can actually be said to be a university question, because there are too many merchants selling fake products, so everyone must keep their eyes open when choosing to purchase, prevent and control the selection of inferior cement, and give themselves Decoration brings hidden dangers. When you choose to buy, you can refer to the precautions given in this article to make a choice and buy a cement with good quality and good price.
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