artificial stone, which is created by mixing water, binder and aggregates (crushed stone, sand or gravel), and their further solidification, called concrete.
as a building material began to be used even in ancient times, the concrete structure which was markedly different from the then current.There was a time when it is temporarily stopped to use, but in the XIX century were invented new hydraulic binders such as Portland cement, concrete and regained popularity in construction.In the 60s of XIX century.It has been improved cement manufacturing technology, brand strength has increased, and it was used as a main binder for concrete.Currently this product - one of the most important materials used in virtually all areas of modern construction.
Such recognition he was due to the following characteristics:
- variety of properties acquired as a result of the variability of the quality of the stone and the use of binders and a variety of methods of physical and chemical and mechanical processing;
- ease of working with concrete mix, which has a high flexibility and allows to manufacture a wide variety of shapes and sizes of durable, high building structures;
- ability to fully mechanize the process of working with concrete;
- economy, as its volume by 80-90% consists of stone aggregates local production.
Production of high quality concrete mix is possible only if the knowledge of technology, skills, material selection of a certain quality and the ability to calculate their ratio, finding methods of packing, sealing and mixing modes.
for the construction of various engineering structures using different types of concrete (depending on application).There are several key features, which classified material: the proportion of concrete, its strength, the type of binder, the appointment and frost.The main classification is made on the bulk weight.Accordingly her concretes are very light, light, heavy and extra heavy.
1. In the first - a significant number of medium and small cells around 1-1.5 mm in size, so they are called honeycomb.Specific weight of the concrete volume of 1 cubic meter is about 500 kg.Typically, this kind is used as an insulating layer.
2. Light.This type includes those which are used as a placeholder simple lightweight materials - expanded clay, tuff, rakushnik, or else do not use any fillers, and foaming agents are added - concrete, foam concrete, and others. The share of volume of one cubic meter of concrete - 500-1800kg.The main part of its members takes the sand - up to 600 kg.Such material is often used for the manufacture of building blocks.
3. As part of the heavy concrete are krupnofraktsionnye heavy aggregates - gravel and crushed stone.One cubic meter of it weighs about 1800-2500 kg.This volume contains a 1150-1300 kg of gravel or crushed stone, sand 600-750 kg, 250-450 kg of cement, 150-200 liters of water.Heavy concrete is a classic and is used in many areas of construction.
4. Particularly heavy concretes are composed of barite, magnetite, and some types of scrap metal.Specific weight of the concrete volume of 1 cubic meter can range from 2,500 to 3,000 kg.The main component of most of its weight is coarse aggregate.This type of concrete is used mainly for the production of protective structures for AEC.
calculating the cubic meter of concrete, we should not forget that its components may have different specific gravity.For example, a small fraction of coarse aggregate harder and quarry sand easier than river.
