mixture of cement

When building a house, often we are faced with technical obstacles. For example, the process of making forms for concrete columns and beams. Another obstacle is the implementation of the wrong building, so the quality decreases. In fact, these things happen when you know the causes and effects that will occur.
Problems and solutions in the dosage of cement, water, sand, gravel, and is just as interesting. Dose that does not fit the plaster was not optimal. In the measurement, you're too much use of cement, water and sand, while the less. To prevent repeated failures, here are some of the problems associated with cement applications, including solutions that can be done.
1.Semen porous (bug holes)
If the formwork is removed from the concrete structure, it seems uneven concrete and many holes as a nest of insects. This case is often referred to as bug holes. The case of this bug only affects the display banunan holes, and not too much influence on the strength of concrete structures.
Cause
There is air trapped in the concrete mixture. The air is displayed when the process of mixing concrete (normal air content in concrete with 2%).
Solution
You can close a perforated surface with a layer of new cement. The results are more flat and looks neat.
PencegahanGunakan water-based mud oil (one of the additives). Such materials can reduce the bug holes (use immediately before the time of 6 hours, then move on to casting) (Add dough composition of sand on the concrete. The sand will push the number of gaps bugs
2.Pengkristalan (efflorescence)
When the wall construction is completed, the crystals on the surface of the wall (under layers of paint).
Cause
This phenomenon is caused by entrainment of alkaline salts to the surface of the plaster, concrete or brick.
SolusiApabila coating is not damaged by weathering, then wipe with a damp cloth and then wait until dry. After the abrasive surface of the paint, so the pores open, so water and alkali salts easily. After the water and the salt does not come out, then the painting ulangJika coating is damaged then the sanding done to make basic. Let stand until water and salt. After drying ulangJika doing the painting had already appeared, it can be used acian ordinary cement to cover the holes
Prevention
In the exposed cement wall applications, this problem will disappear. If the wall with paint, can be prevented by wiping the crystals disappear.
3. Concrete volume shrinkage (shrinkage)
Shrink the volume shrinkage of concrete when the concrete began to dry. Lasts up to 3 days after the casting process. This shrinkage can cause cracking of the concrete appears generally in the form of cracks (width 1-2 mm) and non-structural.
PenyebabPengadukan a total of not less baikKualitas baikKomposisi different mortar (a cement content is too much cement and water factor is too high)
Solution
Cracks caused by shrinkage can be improved by injection Member on the cracked concrete.
Prevention
This problem can be avoided by using cuting compound (concrete nurses) performed after the concrete implementation. Compelling the use of compound instructions aimed at reducing the risk shtinkage ctacking. There are two types of curing compound that can gunakanSodium matetial silicate based. Properties have seeped into the concrete and accelerate the hydration of cement to the surface structure. For perfect results to get more done spraying 1-3 hariWax based material. Shaped membrane on the concrete surface layer that controls the rate of evaporation. For applications in the field using a kind of clear beam curing compound

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