1. Portland cement
The hydraulic cementing material made of portland cement clinker, %~5% limestone or granulated blast furnace slag, and appropriate amount of gypsum is called Portland cement, which is divided into P.I and P.II, which is commonly known as Portland cement abroad.
2. Ordinary Portland cement
A hydraulic cementing material made of Portland cement clinker, 6%~15% mixed materials and a proper amount of gypsum is called ordinary Portland cement (abbreviated as ordinary cement), and its code name is P.O.
3. Slag Portland cement
The hydraulic cementing material made of portland cement clinker, granulated blast furnace slag and a proper amount of gypsum is called slag Portland cement, and its code name is P.S..
4. pozzolanic portland cement
A hydraulic cementing material made of portland cement clinker, pozzolanic mixed materials and a proper amount of gypsum. It is called pozzolanic portland cement, code name: p.p.
5. Fly Ash Portland Cement
A hydraulic cementing material made by grinding Portland cement clinker, fly ash and appropriate amount of gypsum is called fly ash Portland cement, code name: P.F..
6. Composite Portland cement
A hydraulic cementing material made of Portland cement clinker, two or more specified mixed materials and a proper amount of gypsum is called composite Portland cement (referred to as composite cement for short) with code name P.C..
usage and dosage
take 1m2 as an example:
cement mortar quantity 1.15 (average thickness) = .15m3
sand dosage: .15*15kg (sand dosage per m3) =225kg
cement dosage: 225/2.5-9kg.
attention to purchase
1. The cement paper bag is well packed and completely marked. The marks on the paper bag include: industrial cement name, registered trademark, factory name, production license number, variety (including variety code), label, packaging year, month, day and number. Different kinds of cement use different colors, such as red for portland cement and ordinary portland cement, green for slag cement and black for pozzolanic cement and fly ash cement.
2. When you twist cement powder with your fingers, you feel a little bit of sand, fineness and powder, indicating that the fineness of cement is normal.
3. The cement with dark gray or dark green color, yellow and white color (yellow indicates that the clinker is raw material and the amount of white slag is too much) is relatively low in strength.
4. No caking due to moisture. Be sure to see the production date of cement clearly, and cement also has a date of use. The properties of cement that has exceeded the validity period of 3 days have declined. After storage for three months, the strength of cement decreases by 1%-2%, after six months, it decreases by 15%-3%, and after one year, it decreases by 25%-4%. Cement that can't set for more than 12 hours is of poor quality.
5. It is necessary to correctly select cement grade and mix cement sand. The proportion of cement is large, and the bonding strength of ceramic tiles is strong, which can quickly bond red bricks firmly, but the mixing ratio of cement is high, and the expansion coefficient of cement mortar is large, which is easy to crack the bricks after paving. The recommended ratio is 1:3 for wall tiles, 1: 2-3 for floor tiles, and the cement grade of cement is 325 cement.
6. Pay attention to the label when using cement, which indicates the strength of cement. There are 75, 325, 425, 525, 625, 725R kinds of ordinary cement. The larger the label, the better the compressive and tensile strength. Indoor decoration cement-generally choose No.25, but it's best not to exceed No.425 for the cement for wall tiles and floor tiles in home decoration. The higher the label, the greater the expansibility of the cement, which will easily lead to the hollowing of the floor tiles and the tearing or direct falling of the wall tiles.
7. Cement can't be used more than 3 months after delivery, and different brands of cement can't be used indiscriminately.
What are the sands?
According to different diameters, they are divided into coarse sand, medium sand and fine sand.
Natural sand and artificial sand: rock particles with a particle size of less than 5mm formed by natural conditions (mainly rock weathering) are called natural sand. Artificial sand is made by crushing rocks, but it is generally not used because of its high cost and many flakes and powders.
According to technical requirements, it can be divided into three categories:
Class I, which is suitable for concrete with strength grade greater than C6;
class ii, suitable for concrete with strength grade C3-C6, frost resistance and impermeability or other requirements;
class iii, suitable for concrete and building mortar with strength grade less than C3.
Usage and dosage
Generally, the floor can reach the thickness of 4cm, which means 4cm = .4m. If it is a 1m_ two-bedroom building, it needs 4m_ mortar. According to the ratio of sand to cement (2/3), it is almost 2.67 cubic meters of sand, and the general decoration sand is about 2.6 tons per cubic meter, so the floor of 1 square meters is paved with sand.
attention to purchase
1. Choose varieties
There are also many varieties of sand, which are generally divided into three types: river sand, sea sand and mountain sand. The name of this sand is almost related to its source, which must be understood by everyone. In general decoration, the river sand is more brave, and the sea sand is mixed with a lot of salt content, which is easy to be eroded and scratched. After all, sodium chloride is soluble in water, so it is not recommended; In addition, there are too many organic ingredients in the mountain sand, which leads to the fact that although the sand is very cheap, each piece is not pure enough, and it needs to be scoured in the relative equipment area after purchasing, which is a bit uncomfortable. Therefore, most families choose some relatively fine and wet river sand when decorating, which has better stability.
2, the price in the industry
For the owners who buy decoration materials, it is necessary to know a wave of sand for decoration first, otherwise they will not understand the market in the end and will easily be cheated. Generally, there are many kinds of sand. Ordinary medium sand is almost 18 yuan a bag, inferior sand is almost 1 yuan a bag, and some fine sand can reach 3 yuan or even higher. Many people may not understand the concept of this bag, so Xiaobian will tell you about it as a unit. Ordinary river sand is almost 1-2 yuan per cubic meter, and the weight of sand per cubic meter is almost 2.6 tons, that is, the average per ton is between 38-76 yuan.
3. Choose reliable merchants
There are fewer brands of sand, so you need to choose reliable merchants. Although the profit of sand is not big, there are many cases of fishing in troubled waters, such as rubbing sea sand and mountain sand in river sand, which ordinary people can't find, and it is difficult to identify, and it is not worth the loss. Therefore, it is recommended to drag friends to find some reliable merchants.
what are the anticorrosive coatings
1. According to their uses, they can be divided into: duty paint for rubber, duty paint for ship, duty paint for metal, duty paint for automobile, duty paint for pipeline, duty paint for furniture and duty paint for steel structure.
2. According to the resin film formation, it is divided into: epoxy duty paint, perchloroethylene duty paint, chlorinated rubber duty paint, polyurethane duty paint, acrylic duty paint, inorganic duty paint and highly chlorinated polyethylene duty paint.
usage and dosage
1. Improving the essence of metal (alloying treatment)
Many foreign scholars have studied the influence of various alloying elements on the seawater corrosion resistance of steel. It is found that alloy steels based on Cr, Ni, Cu, P, Si and rare earth have excellent corrosion resistance, and on this basis, a series of seawater corrosion resistant steels have been developed. However, due to economic and technological factors, the above elements are not widely used in seawater corrosion-resistant steel.
2. Forming a protective layer (coating a nonmetal or metal protective layer)
The metal protective layer mainly carries out phosphating treatment, oxidation treatment and passivation treatment on the plated metal; Non-metallic protective layer is mainly formed by coating paint, plastic, enamel, mineral grease and so on on the metal surface to form a protective layer. The purpose of these two kinds of protective layers is to isolate the contact between the substrate and seawater instead of the reaction between the substrate and seawater, thus forming protection.
attention in purchasing
1. nature of the environment
when purchasing anticorrosive coatings, we need to consider the environment first, and choose the appropriate anticorrosive coatings according to the environmental location, temperature and humidity. If there is acidic medium indoors, aldehyde resin paint with excellent acid resistance can be used, and if there is alkaline medium indoors, epoxy resin paint with excellent alkali resistance can be used.
2. Feasibility of construction
When purchasing anti-corrosion coatings, we need to pay attention to the feasibility of construction, and we need to adopt a suitable construction method. Usually, we can choose cold-set coatings that are dry and easy to spray.
3. Matching system
When purchasing anticorrosive coatings, we must match the primer, intermediate paint and topcoat. Besides following the instructions of the paint, we also need to match the primer, intermediate paint and topcoat to give full play to the performance of anticorrosive coatings.
Roller brushes can be divided into wool roller brushes and chemical fiber roller brushes according to bristle materials;
According to the length of bristles, it can be divided into: long hair rolling brush, medium hair roller brush and short hair roller brush.
different roller brushes will paint different effects, and the long-haired roller will paint some fine textures, which are concave and convex, similar to the texture effect. After the short hair roller is painted, the paint surface is more uniform and smooth, and there is no concave-convex feeling, and the middle hair is between the two.
Usage and dosage
Roller brushes are mostly made of wool and foamed plastics, which can be divided into coating roller brushes, napping roller brushes, floor paint roller brushes, flat coating roller brushes, etc., and are mainly used for large-area coating roller coating in architectural decoration projects. And can be used for coating and rolling various ready mixed paint, such as latex paint, antirust paint, interior and exterior wall coating, wallpaper pasting adhesive and the like.
attention in purchasing
1. Look at the bristle density
High-quality roller brush, with high plush density, more than 95g square meter, large amount of dipping paint, large brushing area, firm plush, not easy to shed hair and no thread opening. Long service time, smooth surface. The plush density of low-grade roller brushes is below 7 grams per square meter. Loosely woven, easy to shed hair.
2. Look at the purity of the bristles
The quality of the brush head determines the service life and effect of the roller brush. At the same time, 6% of the cost of a roller brush is determined by plush. For example, 1% acrylic fiber has good quality, good dipping and high price, while plush containing a certain proportion of polyester is cheap.
3. Look at the plastic parts
The handle of the roller brush determines the working efficiency and energy consumption during use, so whether the roller brush is a nylon tube is more comfortable and durable.
4. Look at the bearing capacity
In order to test the quality of the roller brush, you can step in the middle of the roller brush head when purchasing. If there is no change in the roller brush, the bearing capacity of the brush head is better. Poor quality roller brushes, when you pinch them with your hands, the plastic parts inside will be broken.
What are the brushes
1. Pig Brush
The high-quality pig brush has the characteristics of large paint content, good elasticity, uniform paint discharge, uniform thickness of the paint surface, difficulty in leaving bristles on the painted surface, and durability. It is especially suitable for paints and glues with high concentration.
2. Wool brush
Wool brush is soft, smooth and well-leveled, and can spray paint evenly, so that the paint surface is smooth and uniform in thickness, and it is not easy to leave brush lines on the painted surface, and it feels smooth and durable during construction. The disadvantage is that it is easy to shed.
uses
paint brushes mainly use paint, glue and grease.
attention to purchase
1. The tapered bristles with thick and thin roots can make the paint brush release paint slowly and evenly, and its overall taper makes it particularly convenient for painting straight lines and tangent places.
2. The brush made of elastic bristles can keep its overall shape.
3. The bristle end is bifurcated, which can absorb a large amount of paint and release paint more evenly (making the paint film smooth and uniform).
4. The length of bristles should be 5% longer than the width of brushes. It is better to dip and release paint when the bristles are longer, and it is easier to brush corners or trim positions.
5. Brushes with long bristles in the middle and short bristles on both sides are easier to use when brushing edges and corners.
6. Use the plug and epoxy adhesive to firmly fix the bristles on the handle, so as not to be pulled out when painting, so as not to stick the bristles on the paint film.
What are the building adhesives?
1. Dry-mixed mortar is classified according to physical form: it is mixed in the factory, and can be used only by adding a certain amount of water on the construction site according to the requirements of the manufacturer. Powder of adhesive material needs to be added additionally. Liquid materials that need to be added with cement and sand.
Ready-to-use slurry: supplied according to construction consistency requirements (indoor use only).
2. According to the parts used:
Ceramic tile adhesive: mainly used for pasting various wall and floor tiles indoors and outdoors.
stone binder: mainly used for bonding various stones such as marble and granite.
Interface treatment agent: mainly used for interface treatment and adhesive for back cover.
Bonding agent for joints and blocks: mainly used for bonding and joint treatment of various partition boards and plasterboards.
putty-scraping glue: mainly used for leveling cement putty.
usage and dosage
building glue is a kind of glue, which is widely used in building engineering and is an essential material in building engineering. It can also be used for road signs, dam leakage prevention and emergency maintenance of military engineering.
attention to purchase
1. Select the products according to the use position or purpose, and avoid using those multi-purpose all-purpose adhesives.
2. For ventilation ducts, metal, wood and other grass-roots or high-temperature environments, ordinary cement-based adhesives should not be used, and paste building adhesives or flexible cement mortar should be used.
3. For liquid adhesives and paste adhesives, in addition to their physical performance indicators, we should also check whether they contain harmful substances such as formaldehyde, toluene and xylene. For powdery adhesives, it is basically unnecessary to consider environmental performance, because harmful substances such as formaldehyde, toluene and xylene will not exist in dry powder materials.