Lightweight Aggregate Concrete

Concrete, Lightweight Aggregate

 

the most common type of concrete, in which lightweight aggregate is used as the coarse filler, cement (more rarely, gypsum, lime, synthetic resins) is used as the binder, and open sand or compact sand (for example, quartz sand) is used as the fine aggregate. In terms of the degree of porosity of the concrete, lightweight aggregate concrete is classified as compact, large-pore (sand-free), or aerated. In terms of purpose, it is classified as thermally insulating, structurally insulating, or structural.

Thermally insulating lightweight aggregate concrete of varying structure is used in buildings basically as a warmth-retaining material in sandwich enclosures. Its density (dry) is between 350 kg per cu m (for example, in large-pore lightweight aggregate concrete with synthetic resins) and 600 kg per cu m. Its compressive strength is 0.5–2.5 meganewtons (MN) per sq m (l MN per sq m = 10 kg-force per sq cm). Its coefficient of thermal conductivity is 0.11–0.17 watts per (m.°K), or 0.10–0.15 kilocalories per (m · hr · °C).

Structurally insulating lightweight aggregate concrete is used chiefly for single-ply wall paneling and large units. Its density is 700–1,200 kg per cu m. Its compressive strength is 3.5–10 MN per sq m. Its coefficient of thermal conductivity is 0.21–0.46 W per (m · °K), or 0.18–0.40 kcal per (m · hr · °C). Its cold resistance is 15–100 Mrz (from 15 to 100 alternating freezing-thawing cycles).

Structural lightweight aggregate concrete is designed for the various supporting structures of buildings and engineering installations (for example, bridges). It has a density of 1,400–1,800 kg per cu m. Its compressive strength is 10–50 MN per sq m. Its cold resistance is up to 500 Mrz. The use of structural light-weight aggregate concrete (instead of ordinary heavy concrete) in large-scale reinforced-concrete structures makes it possible to reduce the weight and cost of the structures substantially. High-grade structural concrete is also used in shipbuilding (for example, for the hulls of riverboats and seagoing vessels).

REFERENCES

Stroitel’nye materialy. Edited by M. I. Khigerovich. Moscow, 1970.
Buzhevich, G. A. Legkie betony na poristykh zapolniteliakh. Moscow, 1970.

G. A. BUZHEVICH

References in periodicals archive ?
It was also found that the properties of aggregates made from crushed concrete and the effect of the aggregates on the new concrete (strength, modulus of elasticity, etc.) resemble those of lightweight aggregate concrete.
Using the lightweight aggregate (LWA) together with normal-weight fine aggregate in concrete mixtures is an effective method to produce lightweight aggregate concrete (LWAC).
Berntsson, "6-lightweight aggregate concrete microstructure," in Lightweight Aggregate Concrete, pp.
"Bond Strength of Steel Deformed Rebars Embedded in Artificial Lightweight Aggregate Concrete." Journal of Adhesion Science and Technology 27 (5-6): 490-507.
Based on the classification of lightweight concrete according to the level of compressive strength and aggregate type by Mindess and Young [4], lightweight aggregate concrete using artificial lightweight aggregate (ALWA) or lightweight coarse sintered fly ash and foamed slag aggregates can produce compressive strength values of 17-41 MPa with a density range of 1500-2000 kg/[m.sup.3] [4].
Eight full scale rectangular cross-section columns filled with lightweight aggregate concrete and normal weight aggregate concrete, four specimens each, were tested under axial loads for comparison purposes.
LWC can either be foamed concrete, lightweight aggregate concrete or autoclaved aerated concrete.
Lightweight Aggregate Concrete. In: Noyes Publications 2003; p.
The 75 papers include discussions of such topics as welding properties and fatigue resistance of S690QL high-strength steels, hardening the surface of austenitic stainless steel by explosive treatment, surface properties of lightweight aggregate concrete and its correlation with durability, electrochemical impedance spectroscopy as a prospective tool for characterizing the intermetallic microstructure of lead-free solder, and estimating thermal boundary conditions by using a hybrid inverse approach.

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