Many mistakes could happen if we are not familiar with concrete supplies. One of them is adding water to the concrete mix. The concrete mix has been weighed with the proportions of each material, according to its specific gravity. It has a water-cement factor with a certain value. The water-cement factor (f.a.s or w/c water per cement ratio) is the value of the ratio of the amount of water divided by the amount of cement in units of weight.

The water-cement factor is the main determinant of the strong character of concrete. Therefore, it is not allowed to add water to maintain the strength of the concrete. If the addition of water still has to be done due to certain conditions, add cement in an appropriate amount according to the addition of water.

Ready-mix concrete must be dismantled as soon as possible to avoid the initial setting, which is a condition where cement and water begin to react with hydration and the concrete mix begins to harden. Generally characterized by an increase in the temperature of the concrete and an increase in the viscosity of the concrete within 3-4 hours. The duration of the demolition of the concrete is only determined by the readiness of the field, the number of workers/builders and, the type of structure being worked on.

The ground floor slab is certainly easier to work with than the 3rd-floor slab, or column. If the type of structure being worked on is difficult and it is estimated that demolition of concrete will take a long time, adjust the volume of concrete ordered or prepare more demolition power. If the volume of concrete in large quantities is above 5 m3 and the location is above, it is highly recommended to use a concrete pump so that the working time is more efficient and the quality of the concrete is maintained.