It is usually believed that the concrete dries after mixing and laying. Actually, the concrete does not become solid because the water evaporates, but the cement hydrates, glues the other components together and finally forms a rock-like material. Concrete is used to make road pavement, building structures, foundations, roads, pedestrian bridges, parking structures, bases for fences / gates, and cement in brick or block walls. The old name for concrete is molten rock.
In its development, many new modified concrete found, such as lightweight concrete, spray concrete (eng: shotcrete), fiber concrete, high strength concrete, very high strength concrete, compressed concrete itself (eng: self compacted concrete) etc. Nowadays concrete is the most widely used building material in the world.
The use of concrete and volcanic materials such as ash pozzolan as its formation has begun since Greek and Roman times maybe even before. With a mixture of lime, pozzolan and pumice, the Romans built many infrastructures such as aqueducts, buildings, drainage and others. In Indonesia similar uses can be seen in some of the remaining ancient buildings. The Indrapatra fort in Aceh which was built in the 7th century by the kingdom of Lamuri, the building materials in the form of limestone, clay, and mountain rock. Egyptians have discovered beforehand that using volcanic dust additives can increase concrete compressive strength.
Massive use of concrete begins at the beginning of the 19th century and is the beginning of the era of reinforced concrete. In 1801, F. Coignet published his writing on the principles of construction by reviewing the moisture of the concrete material against the taruk. In 1850, J.L. Lambot for the first time made a small cement ship to be exhibited at the Expo in 1855 in Paris. J.Moiner, a park expert from France patented the metal frame as a concrete reinforcement to overcome the powder used for his plants. In 1886, Koenen published a paper on the theory and design of concrete structures. C.A.P Turner developed a beamless slab plate in 1906.
Advantages and disadvantages of concreteThe advantages of concrete are easily formed according to construction needs. Besides that, the concrete also has high strength, is resistant to high temperatures and low maintenance costs.
While the shortcomings are forms that have been made difficult to change without damage. In concrete structures, if you want to do the destruction it will be expensive because it cannot be used anymore. Different from steel structures that remain valuable. Weight, compared to its strength and great reflective power.
Concrete has high compressive strength but is weak in drag. If the structure is straightforward and not given enough reinforcement, it will easily fail. According to rough estimates, the tensile strength value is about 9% -5% compressive strength. Therefore reinforcement is needed in concrete structures. General reinforcement is by using steel bones which, if combined, are often called reinforced concrete.
Properties of concreteAs mentioned before, concrete has a high compressive strength but weak tensile strength. For compressive strength, in Indonesia units of kg / cm² are often used with the symbol K for cube and fc specimens for cylindrical specimens. The crush strength of concrete is strongly influenced by several factors:
Type and quality of cement
- The type and curvature of the surface plane molecules are aggregate. The fact shows that aggregate use will produce concrete with compressive strength and tensile strength greater than the use of fine gravel from the river.
- Care. Power loss of up to about 40% can occur if drying is carried out prematurely. Maintenance is a very important thing in field work and in making test materials.
- Temperature. In general, the hardening speed of the concrete increases with increasing temperature. At freezing the compressive strength will remain low for a long time.
- Age. In the normal state of concrete strength increases with age.
Concrete MixConcrete mix has for decades been a practical solution to easier construction. Unlike the concrete site mix, this concrete provides more convenience.
This concrete is also called concrete mix. The making of fresh concrete is done in a batching plant and then sent to the construction site using Molen's fleet. In short, the difference with the site mix is at the mixing location. Site mix is concrete which mixes at the construction site.
Concrete mix is also known as instant concrete. Some concrete companies are now able to produce this type of fresh concrete and reach several regions.
Concrete mix is a concrete mixture of Portland cement, fine aggregate, coarse aggregate and water. This mixing process is carried out in the batching plant. Then sent using a mixer truck to the construction site. To maintain the quality of fresh concrete during the trip, added material is used (if needed).
In addition, to maintain the quality of fresh concrete, the location between the batching plant and the construction location should not be too far away. This is because it will reduce the level of concrete slump that has been predetermined.
Through mixer trucks, fresh concrete experiences stirring at a certain speed. Therefore, the concrete remains in good condition until it is ready to be poured on location.
In quality, mix concrete and site mix are not different. It's just that instant concrete gets tighter supervision in the batching plant. Starting from the selection of raw materials and the mixing process, everything is done with expert control.
Concrete vs cementThe main difference between concrete and cement is that concrete is a mixed material made of water, aggregate and cement.
Cement is a fine powder made from limestone and other minerals that can absorb water and act as concrete adhesives. While cement is a separate building material, concrete cannot be made without cement.
These two terms are often mistakenly exchanged for use, although concrete and cement are actually clearly different products.
CementCement is made of limestone, calcium, silicon, iron, and aluminum and other materials. This mixture is heated in a large combustion device until the temperature is around 1,482 ° C so it becomes a product called clinker, which looks like marble at a glance.
The clinker is then crushed into powder and added gypsum to become gray flour which we call cement. When water is added to cement, the water will spur a chemical process that will make the cement harden.
Portland CementThere are many types of cement, but the most commonly used in construction is Portland cement. Joseph Aspdin from England developed this building material in the 1700s when he discovered that adding clay to the limestone and then the mixture was heated would cause the mixture to be applied everywhere.
Portland cement is a type of hydraulic cement which means that when water is added, water will trigger a chemical reaction that does not depend on the amount of water added. This allows the cement to harden even though the water is small and remains strong in wet / humid conditions. Different types of hydraulic cement are mostly used in making concrete and stucco.
ConcreteIn contrast to cement, concrete is a woodworking material that uses cement to unite rock, coral and sand, which is also called aggregate.
Cement composes from 10% to 15% of the total concrete period; exact proportions vary depending on the type of concrete to be made.
The aggregate and cement material will be stirred with water which triggers a chemical reaction and makes the cement harden and the concrete is made.
Before the hardening process occurs, the concrete mixture can be poured into a mold so that the mixture will harden in a certain form such as a block or maybe a cylinder.
The length of time until the concrete is finished depends on how much gypsum is added to the mixture. The manufacturing time can be accelerated by adding calcium chloride or it can be slowed by adding sugar.
These compounds work by influencing the development of hardening crystals that form when concrete is made. Concrete exposed to conditions that can freeze or melt it can add other chemicals to prevent cracking.
9 Types of concreteIn construction, concrete is a composite building material made from a combination of aggregates and cement binders. The most common form of concrete is Portland cement, which consists of mineral aggregates (usually gravel and sand), cement and water.
There are various types of concrete including:
1. Cyclical concreteThis type of concrete is the same as normal normal concrete, the difference is that in this concrete a relatively large aggregate size is used. This concrete is used in the manufacture of dams, bridge bases, and so on. The size of coarse aggregates can be up to 20 cm, but this aggregate proportion greater than usual should be no more than 20 percent of the total aggregate.
2. Lightweight concreteThis type of concrete is the same as concrete, the only difference being that the coarse aggregate is replaced by light aggregates. In addition, it can also be used with ordinary concrete with added ingredients that are able to form air bubbles when the concrete stirring takes place. This kind of concrete has many pores so that its specific gravity is lower than ordinary concrete.
3. Non-sand concreteThis type of concrete is made without sand, so it's only water, cement, and gravel. Because without sand, the gravel cavity is not filled. So that hollow concrete and specific gravity are lower than ordinary concrete. In addition, because without sand, no paste is needed to cover sand grains so that the need for cement is relatively less.
4. Hollow concreteAs is well known that about half of the water mixed with reacts with cement, while the other half is used to thin the mixture. This type of concrete is stirred and poured and compacted as ordinary concrete, but after the concrete is densely printed then the remaining reaction water is sucked in a special way. Like a vacuum. Thus the water left behind is only water used for reaction with cement, so that the concrete obtained is very strong.
5. Reinforced concreteOrdinary concrete is very weak with tensile forces, but very strong with compressive forces, steel rods can be inserted into concrete parts that are interested in helping concrete. Beto, which is entered by steel rods on the pull part, is called reinforced concrete.
6. Prestressed concreteThis type of concrete is the same as reinforced concrete, the difference is that the steel bar inserted into the concrete is stretched first. This steel rod still has tension until the poured concrete hardens. This part of the concrete block, although holding the bending will not crack.
7. Precast concreteOrdinary concrete is printed / poured in place. However, it can also be printed in other places, its function is printed in other places in order to obtain better quality. Besides that it is used if the concrete manufacturing site is very limited. So it is difficult to provide a concrete treatment plant.
8. Mass concreteConcrete is poured in large volumes, namely the ratio between the volume and the surface is large. If the dimensions are greater than 60 sm. Large foundation, pillar, dam. Temeratur differences must be considered.
9. Ferrous cement
A composite material obtained by giving orthar cement a reinforcement in the form of a steel wire woven.
10. Fiber concreteComposite concrete consisting of ordinary concrete and other materials in the form of fiber. Fiber in the form of stems 5 to 500 mm, length 25-100 mm. Asbatos fibers, sprouts, plastic fibers, steel wires.
- how to make concrete
- concrete material
- what is concrete made of
- uses of concrete