Concrete Basics (2) Characteristics of Concrete

There are four main characteristics of concrete, namely:Workability, Cohesiveness, strength, and durability.
Concrete has three stages of the condition, namely:Plastic, Setting, and Hardening.STAGES OF CONDITION OF CONCRETE

Plastic phase. When the materials first concrete is mixed, shaped like a "batter". Soft, watery, so can poured and formed into a variety of forms. This stage is called the condition of plastic. Concrete must be in plastic condition when pouring (casting) and compaction (compaction).
The most important characteristic in this plastic condition is the workability and cohesiveness.
Our feet would sink if you tried to stand on concrete that is still in plastic condition

Setting Stage. Furthermore, the concrete will begin to harden and numb. When the concrete is no longer soft, and begins to harden, the condition is called setting. Setting occurs after compaction (compaction) and final polishing (finishing). Muddy wet concrete as placed would be easier but more difficult to do the finishing.
If we set foot on the concrete was setting, our feet will not sink, but our footprints will appear on the surface of the concrete.

Hardening stage (hardening). After going through the stage setting, the concrete begins to harden and achieve power. Characteristics present at this stage is the strength and durability (endurance).

Workability
Workability is the ability to be carried out or treated, including how concrete is easy to carry and placed everywhere, easily done, easily compacted, and easy to do the finishing.
Concrete which tends to "dry" water shortage alias of course rather difficult to set up, hard to move, even later finished to hard. If not constructed properly, concrete will not be strong and durable.
Workability of concrete can be tested by conducting slump tests. This test will be discussed in Section 3.
Anything that affects the workability?

   1. Amount of cement paste (mortar). Cement paste is a mixture of cement and water. The more cement paste mixed with coarse and fine aggregate, the greater the workabilitynya.
   2. Aggregate gradation levels. Well-graded (well-degradable), smooth surfaces and rounded shapes tend to tend to increase the workability of concrete mix.
To improve workability, can be done with

    * Adding cement paste (water + cement)
    * Use well-graded aggregate
    * Using the admixture
Warning!But avoid increased workability by adding only water, can cause menurangi strength and durability of concrete.

Strength and endurance.
A good concrete made of strong materials and durable in nature. That is, if the material forming the concrete is strong and resistant, can be secured by concrete that is produced is also more robust. Characteristics of concrete are strong and have high endurance are: solid, water-resistant (not porous), resistant to temperature change, and resistant to wear and weathering.
Strength and endurance are related. The higher the strength (quality) of concrete, the higher the durability.
Concrete is a very important to protect the steel reinforcement in the concrete core. Concrete strength is usually measured with Concrete Strength Test. About this test will also be discussed in Section 3.

Strength and endurance is determined by:

   1. Compaction. This compaction aims to eliminate air in the concrete. Of course compaction was done when the concrete is still liquid.
   2. Maintenance (Curing). Curing is the "wet" concrete has set (hard) for some time. The aim is to reduce excessive water evaporation, so water is in the concrete mixture can react optimally. The longer the curing process, the higher the durability of concrete produced.
   3. Weather. The rather warm weather can make achieving high strength concrete in the not too distant.
   4. Types of Cement. Different types of cement was also influenced by the strength and durability of concrete.
   5. Water to cement ratio, commonly referred to w / c ratio. Most water or cement can result in concrete kekuarangan become stronger and certainly not durable. W / C ratio is the ratio of water to the HEAVY WEIGHT cement. Because the weight of one liter of water equal to 1 kg, so people use more water volume ratio (in liters) of cement WEIGHT (in kg).