2 Concrete, referred to as "concrete (tóng)": refers to the general name of engineering composite materials whose aggregates are bonded into a whole by cementing materials. Generally speaking, the term concrete refers to cement as cementing material and sandstone as aggregate; Cement concrete, also known as ordinary concrete, is made by mixing cement and water (with or without additives and additives) in a certain proportion, stirring, molding and curing, and is widely used in civil engineering.
Extended data:
Cement-soil: a consolidated body formed by mixing cement slurry with soil through grouting, deep mixing and high-pressure jet grouting.
Function and scope of application: Cement-soil technology is mainly used for seepage prevention and supporting projects of bridges, culverts, gates and other channels in small-scale farmland water conservancy projects, and can also be used for dam slope protection, road stability layer, large-scale channel cushion and so on. , especially in areas lacking gravel materials.
Advantages of cement-soil
1 cement soil has the outstanding advantages of using local materials, reducing transportation, convenient construction and low price. The amount of cost savings mainly depends on the transportation distance of sand and gravel. Compared with C 15 cement-soil compacted by local soil (dry state), the cost of C 15 concrete with sand and gravel transportation distance of 80 ~100km can be saved by 40% ~ 50%. The extensive popularization and application of cement-soil technology can achieve remarkable economic benefits.
Cement-soil technology is suitable for canal seepage control and small-scale farmland water conservancy projects in areas lacking gravel materials, and also suitable for cushion materials of large-scale canals and roads. In addition, it can also be used for dam slope protection and other projects.
According to its apparent density, concrete can be divided into heavy concrete, ordinary concrete and light concrete. The difference between these three kinds of concrete is the difference of aggregate.
4 Heavy concrete is made of extremely dense and heavy aggregate with apparent density exceeding 2500 kg/m3. Such as barite concrete and steel chip concrete. , not affected by x-rays and γ-rays; It is usually made of barite and iron ore.
Ordinary concrete is commonly used in buildings, and its apparent density is 1950 ~ 2500 kg/m3. Mainly made of sand and stone, it is the most commonly used concrete variety in civil engineering.
Light concrete is concrete with apparent density less than 1950kg/m3. It can be divided into three categories:
1. lightweight aggregate concrete, its apparent density is 800 ~ 1950kg/m3. Lightweight aggregate includes pumice, volcanic slag, ceramsite, expanded perlite, expanded slag and slag.
2. Porous concrete (foamed concrete, aerated concrete), its apparent density is 300 ~ 1000 kg/m3. Foam concrete is made of cement slurry or cement mortar and stable foam. Aerated concrete is made of cement, water and gas-generating agent.
3. Macroporous concrete (ordinary macroporous concrete and lightweight aggregate macroporous concrete) does not contain fine aggregate. The apparent density range of ordinary macroporous concrete is 1500 ~ 1900 kg/m3, which is made of crushed stone, soft stone and heavy slag. The apparent density of lightweight aggregate macroporous concrete is 500 ~ 1500 kg/m3, which is made of ceramsite, pumice, broken bricks and slag.
References:
Baidu Encyclopedia-Concrete? Baidu encyclopedia-cement soil