Concrete is a building material of artificial origin, which is made on the basis of a specific dense mixture. A notable feature of concrete is its quick solidification, therefore, during use, a special device is involved - a rotating concrete mixer. Is it possible to keep concrete liquid in this state, or will it harden sooner or later?

Properties and features of concrete

Concrete production is a laborious process, despite the simple production technology. Its essence boils down to the correct selection of components and their proportions. The dry mix consists of cement, crushed stone and sand. Also a mandatory component is water. There are several brands of concrete, each of which is intended for specific purposes. For example, asphalt concrete does not contain water.

Interesting fact: The concrete of civilization was known several millennia BC. In any case, this is evidenced by the find of archaeologists on the banks of the Danube. They discovered a hut that was built from a mixture of cement, sand, gravel and water. At the same time, the building had a floor with a thickness of 25 cm. The find dates back to 5600 BC.

The basis of concrete is cement, which in dry form is a homogeneous, loose mixture of a gray tint. If you add water, it turns into a paste. It is cement that acts as a binder component. It contains limestone.Upon contact with water, it crystallizes and then solidifies.

To obtain quality material, you must carefully observe the proportions. In particular, this applies to the addition of water. Each concrete brand is accompanied by clear instructions for mixing the components.

A common mistake is to add too much water. Concrete in this case becomes more mobile, making it convenient to work with. But excess fluid affects the main quality of the material - strength.

The spread of concrete in construction is explained by its advantages, such as compressive and bending strength, workability, resistance to subzero temperatures and moisture. Before putting into operation, concrete passes several tests with which its properties are confirmed.

How does concrete harden?

The process during which concrete solidifies is called polymerization. It consists of several stages - setting and hardening. After what period of time the mixture begins to set, depends on the external conditions and the characteristics of the cement grade. On average, this process takes several hours.

Hardening also takes a long time. During this period, cement hydration occurs - a reaction in which cement and water enter. The duration of complete hardening and the set of concrete strength depends on the purpose for which it is used. For example, the foundation takes about a month to fully harden.If the object is not subjected to severe load, it will be enough to wait about a week.

Concrete hardening is inevitable and the concrete mixer cannot interfere with this process.at. Constant mixing of concrete inside it contributes to the uniformity of the mixture. The setting of the material sets off a little, but the cement hydration reaction is still started. After about an hour, the mobility of the mixture will decrease by 25%.

Concrete mixer in conjunction with special additives can slow down hardening by 2-4 hours. This is important if concrete needs to be transported to a construction site. Cement hydration continues in slow motion, but sooner or later the mixture will harden in a concrete mixer. Due to mixing, individual stone clods may form.

Interesting fact: Concrete is associated with construction, in particular with the construction of massive buildings that have been around for decades. But in the past, even ships were built with it. In 1867, Frenchman Joseph Monier patented reinforced concrete. But back in 1849, a boat was built from it, which a few years later was presented in Paris at an exhibition.

The main components of concrete are cement, sand, gravel and water. The quality of the material depends on the correct selection of proportions. After mixing all the ingredients, cement and water react. This starts the process of cement hydration, which is already impossible to stop. Concrete hardening begins with setting and ends with hardening. This takes from a few days to a month - depending on the brand of cement and the purpose of the material. A concrete mixer can only slow down concrete hardening by 2-4 hours, but as a result, it will still begin to dry out.