Concrete refers to the mixing of cement, sand, stone and water according to a certain proportion, it is also known as ordinary concrete, widely used in civil engineering. The followings are the types and strength grade of concrete for construction.
Sand fills the spaces between stones.
Cement slurry mixed from Cement and water to fill the gaps of sand and stone, and warp in the surface of sand and stone. The cement slurry plays the role of filling, lubricating and cementing.
Sand is called fine aggregate, stone is called coarse aggregate. The coarse and fine aggregates generally do not react with cement, mainly play the role of skeleton and inhibit the volume deformation of cement stone.
Types of Concrete
Based on strength grade:
1. Ordinary concrete: according to national standards, concrete with 28-days compressive strength less than C30 is called the ordinary concrete.
2. High-strength concrete: according to national standards, concrete with 28-days compressive strength in the range of C30 to C80 is called high-strength concrete.
3. Ultra-high strength concrete: According to national regulations, concrete with 28-days compressive strength greater than C80 is called ultra-high strength concrete.
Based on cementing materials
1. Norganic cementing material concrete: including lime siliceous cementing material concrete, Portland cement system concrete (such as Portland cement, ordinary cement, slag cement, fly ash cement, volcanic ash cement, early strength cement concrete, etc.). Calcium aluminum cement system concrete (such as high aluminum cement, pure aluminate cement, jet cement, super hard cement concrete, etc.), gypsum concrete, magnesium cement concrete, sulfur concrete, sodium silicate silicate concrete, metal concrete (metal instead of cement as bonding material), etc.
2. Organic cementing concrete: organic cementing concrete mainly includes asphalt concrete and polymer cement concrete, resin concrete, polymer impregnated concrete and so on. In addition, inorganic and organic composite colloidal material concrete can also be divided into polymer cement concrete and polymer indigo concrete.
Asphalt concrete is a mixture of artificially selected mineral materials (crushed stone or crushed gravel, stone chips or sand, mineral powder, etc.) with a certain proportion of asphalt materials, mixed under strict control conditions. Asphalt concrete is a type of concrete commonly used to build roads, parking lots and other pavement types.
Based on the apparent density
1. Heavy concrete is the high-density concrete with an apparent density greater than 2500 kg/m3, it is made of exceptionally dense and heavy aggregates. Such as barite concrete, steel chip concrete, etc., they have the performance of X-ray and gamma rays; It is often made of barite and iron ore.
2. Ordinary concrete is commonly used in construction, with the apparent density of 1950 ~ 2500 kg/m3, its main aggregates are stand and stone.
3. Lightweight concrete is the apparent density of less than 1952m/m3. It can be divided into three categories:
A. Light aggregate concrete is apparent density of 800 to 1950 kg/m3, light aggregate including pumice, cinder, ceramic particles, expanded perlite, expanded slag, slag and so on.
B. Porous concrete (foam concrete, aerated concrete) is apparent density of 300 ~ 1000 kg/m3. Foamed concrete is made of cement slurry or cement mortar with stabilized foam. Aerated concrete is made of cement, water and aerating agent.
C. Large hole concrete (ordinary large hole concrete, light aggregate large hole concrete), its composition without fine aggregate. The apparent density range of ordinary large-hole concrete is 1500 to 1900kg/m3, which is prepared with crushed stone, soft stone and heavy slag as aggregate. The apparent density of lightweight aggregate large-hole concrete is 500 to 1500 kg/m3, and it is prepared with ceramic particles, pumice stone, broken brick, slag, etc., as aggregate.
Based on function
It can be divided into structural concrete, thermal insulation concrete, decorative concrete, waterproof concrete, refractory concrete, hydraulic concrete, Marine concrete, road concrete, radiation proof concrete, etc