Hardened concrete is a type of concrete that is strong and have the capacity to bear the structural as well as service loads that are applied to it. Hardened concrete is one of the strongest and durable construction material s.
Hardened concrete is concrete that is completely set and able to take the loads. In this article, we will go through the properties of Hardened concrete.
The strength of the concrete plays a vital role in the construction of any building. The strength of the concrete helps to identify whether the concrete can be used in construction or not. The strength of the concrete is defined as the maximum amount of load which the concrete can bear. Strength is considered as one of the most important and valuable properties of concrete. The strength of the concrete gives the overall idea of quality of the concrete and the materials used in the manufacturing of the concrete.
The concrete is tested for three types of strength which are compressive strength , tensile strength, and flexural strength. When we talk about the strength of the concrete we are generally considered compressive strength, because we know that concrete is strong in compression and weak in tension. The concrete is mainly used for its compressive strength. Flexural strength of the concrete is defined as the measure of an under-reinforced concrete beam or slab to resist failure in bending.
Aggregates are the essential component part of the concrete. It will give volume to the concrete. The aggregates which are used in the manufacturing of the concrete should have high compressive strength so that it will produce concrete with good strength.
The aggregate which has sharp edges and rough texture will develop a strong bond between cement. Aggregates with a smooth texture and rounded shape result in a weaker bond between cement and aggregate. The strength of the concrete depends upon the water-cement ratio used during the manufacturing of the concrete. The compressive strength of the concrete decreases with an increase in the water-cement ratio. The optimum water content should be used to ensure the complete hydration of the cement.
Cement is a binding material that is used to bind sand and aggregates with each other to form hardened concrete. Finer the size of the particles of the cement more will be the ultimate compressive strength.
The cement which has a higher composition of tricalcium silicate will develop concrete with higher strength. Admixtures are added to the concrete to achieve the desired property of the concrete. Admixtures in the concrete helps to improve the compressive strength. The weather conditions are also one of the factors which affect the compressive strength of the concrete.
The concrete which is casted in the hot climate and the concrete which is casted in the cold climate has different values of compressive strength. It is very necessary that proper and adequate curing should be done to obtain maximum compressive strength of the concrete. Incomplete curing can cause a loss in the compressive strength of the concrete.
The method which is used in the preparation of the concrete also plays a vital role which also affects the overall strength of the concrete. So that it is very necessary that skilled worker should work during the manufacturing of concrete otherwise we cannot achieve the desired strength in spite of using cement and aggregates in the concrete. Impermeability is the one of the properties of hardened concrete which resists the flow of water through its pore.
Permeability directly affects the durability of the concrete so it is very necessary that the concrete should be less permeable. Excess of water-cement ratio may develop pores or cavities in the concrete which makes the concrete permeable. Durability is also an important factor which affects the quality of the Hardened concrete.
The durability of the concrete can be defined as the capacity of the concrete to bear all the forces of the deterioration. Durability is also known as the period of existence of the concrete without getting adversely affected by Aggressive environmental conditions. There are various causes that affect the durability of the hardened concrete which are Frost action, chemical reaction, alkali-aggregate reaction. The paste i. Hardening does not start as soon as cement and water are mixed, but after a certain length of time known as the "initial set time" during which the concrete can be mixed, transported, laid and vibrated.
Go to content - Go to main menu - Go to search. Top of the page Go to content Back to home page. Le site Planete-TP. Partner websites. You'll find concrete bricks and birdbaths, swimming pools and sailboats. And in years to come, we may even build with it on the moon. Concrete is a unique building material. It doesn't rot or burn like wood. It won't rust and it's heavy—when you build something out of concrete, you know it will be around for some time.
Most of all, though, concrete is special because it starts out as a thick liquid that can be molded in various shapes. Like Baking A Cake To understand the nature of concrete, it might help to think of a cake—a fruitcake. To make one, you mix up some flour, baking powder, butter and eggs, add dried fruit and nuts and pour the whole thing into a cake pan. Apply heat for a while, and presto—that unappetizing paste is suddenly something new. The original batter has changed, while the fruit and nuts are pretty much the same—just suspended and held together by the cake.
Well, concrete isn't exactly fruitcake but there are similarities. In place of the flour mixture, concrete requires portland cement. Instead of dried fruit and nuts, you have sand and gravel. And a concrete form takes the place of the cake pan. Finally, instead of the heat that bakes the cake, concrete uses water.
While heat is the prime mover in getting the cake batter to change its characteristics, in the concrete mix it's water that gets things going.
Perhaps the most important thing to understand about concrete is the role of water. First, it provides plasticity so the concrete can be poured in a form. Its real importance, however, is in the hardening process.
Wet concrete doesn't harden by drying. Instead, the water is a chemical component in a curing process. The compounds that react with the water are in the portland cement.
Isle Of Portland While cement in one form or another has been around for centuries, the type we use was invented in in Britain. It was named portland cement because it looked like the stone quarried on the Isle of Portland.
Portland cement is produced by mixing ground limestone, clay or shale, sand and iron ore. This mixture is heated in a rotary kiln to temperatures as high as degrees Celsius.
The heating process causes the materials to break down and recombine into new compounds that can react with water in a crystallization process called hydration.
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