Why concrete needs reinforcement
Leading the conversation on concrete, reinforced concrete can not forget.Due to the exceptional qualities, it is widely used in modern construction.Reinforced concrete & ndash;is primarily concrete, steel rods which are introduced called reinforcement.The word ";reinforcement ";& Ndash;Italian origin and translated into Russian means ";weapons ";Why should ";reinforced ";concrete?
On building structures are compressive and tensile.Because of this design are deformed.For example, you can clearly imagine the two forces, if you take an ordinary rubber band, put it on two pillars, and click on it in the middle.Gum shrinks at the top, but it will stretch at the bottom.In the middle part of the same length of gum will not change.That imaginary line that divides into two parts, gum & ndash;compressed and stretched, is called the neutral axis.When working on a concrete structure is obtained by bending a similar pattern of deformation.
Reinforced Concrete Flexural destroyed at very low load.Strength as a steel rod in tension at 100 & ndash;200 times higher than that of concrete.So, if you get both materials (concrete and steel) to operate as a unit, t.e.achieve the same strength in the compression zone and tension zone bent structure, it can be increased by several times the strength of structures on the bending.To this end, the stretched portion is administered several steel rods (rebar) of a certain section.Now the design does not break when bent and can withstand many times the failure load.
One might ask, how can work together in one design, two such dissimilar materials such as concrete and steel?
The whole point of their properties:greater compressive strength;high strength reinforcing steel in tension;greater holding power of concrete and steel;almost the same length change of concrete and steel when the temperature.
Due to the strong adhesion of concrete with rebar, it can not pull out. Hardening:/ / Beton2006.ru / list / Rastvor-i-beton / "> concrete shrinks and compresses the valve, and thus even more strongly adheres to it.Bond strength of reinforcement will increase with time and the larger, denser and more concrete the surface roughness of reinforcement.
Very low thermal conductivity of concrete is very useful for concrete structures:concrete reinforcement is well protected from sudden temperature changes.