Lightweight aggregate concrete (LGC), one of the new building materials, is a lightweight concrete made of lightweight aggregate with a bulk density of no more than 1900kg / m3, also known as porous aggregate lightweight concrete.
Lightweight aggregate concrete has the characteristics of light weight, good thermal insulation and fire resistance. Compared with the ordinary concrete of the same grade, the compressive strength of the structural lightweight aggregate concrete can be up to 70 MPa, which can reduce the dead weight by more than 20-30%. The structural thermal insulation lightweight aggregate concrete is a kind of wall material with good thermal insulation performance, and its thermal conductivity is 0.233-0.523 w / (m * k), which is only 12-33% of that of ordinary concrete. Lightweight aggregate concrete has good deformation performance and low elastic modulus. In general, the shrinkage and creep are also large. The elastic modulus of lightweight aggregate concrete is directly proportional to its bulk density and strength. The smaller the bulk density and the lower the strength, the lower the elastic modulus. Compared with ordinary concrete of the same grade, the elastic modulus of lightweight aggregate concrete is about 25-65% lower.
Lightweight aggregate concrete is widely used in industrial and civil buildings and other projects, which can reduce the weight of the structure, improve the seismic performance of the structure, save the amount of materials, improve the efficiency of component transportation and hoisting, reduce the foundation load and improve the building function (thermal insulation and fire resistance, etc.). Therefore, in the 1960s and 1970s, the production and application technology of lightweight aggregate concrete developed rapidly, mainly in the direction of light weight and high strength. It was widely used in high-rise, long-span structures and enclosure structures, especially in the production of small hollow blocks for walls. China began to develop lightweight aggregate and lightweight aggregate concrete since the 1950s. It is mainly used for large-scale exterior wall panels and small hollow blocks in industrial and civil buildings, and a small amount is used for load-bearing structures and thermal structures of high-rise and bridge buildings.
Main types of lightweight aggregate concrete
Lightweight aggregate concrete is divided into natural lightweight aggregate concrete according to the types of lightweight aggregate. Such as pumice concrete, cinder concrete and porous tuff concrete. Artificial lightweight aggregate concrete. Such as clay ceramsite concrete, shale ceramsite concrete, expanded perlite concrete and organic lightweight aggregate concrete. Industrial waste lightweight aggregate concrete. Such as cinder concrete, fly ash ceramsite concrete and expanded slag bead concrete.
According to the type of fine aggregate, it can be divided into: all lightweight concrete. Lightweight aggregate concrete using light sand as fine aggregate. Sand light concrete. Lightweight aggregate concrete with part or all ordinary sand as fine aggregate.
According to its use, it can be divided into: thermal insulation lightweight aggregate concrete. Its bulk density is less than 800 kg / m3, and its compressive strength is less than 5.0 MPa. It is mainly used for thermal insulation envelope and thermal structure. Structural thermal insulation lightweight aggregate concrete. Its bulk density is 800-1400kg / m3, and its compressive strength is 5.0-20.0 MPa. It is mainly used for reinforced and unreinforced enclosure structures. Structural lightweight aggregate concrete. Its bulk density is 1400-1800 kg / m3, and its compressive strength is 15.0-50.0 MPa. It is mainly used for load-bearing members, prestressed members or structures.