1. Field of the Invention
The present invention relates to a recyclable formwork whose used condition can be easily known. The recyclable formwork is represented by a plastic formwork. The recyclable formwork, however, may be not only the plastic formwork but also a metal formwork, especially a formwork of aluminium, iron, or steel, as long as characteristics thereof, such as weight, price, or the like are suitable.
2. Description of the Related Art
Countermeasures against greenhouse gas represented by carbon dioxide are important subjects in which human beings should immediately aim to solve. Carbon dioxide reduction should be strongly carried out without damaging the economy. The inventors will discuss a new proposition in a field of formworks used for curing concrete.
Until now, formworks are mainly concrete panels made of tropical wood.
Instead of the concrete panels of wood, plastic formworks are developed and used. Some types of the plastic formworks can be perfectly recycled and are regarded as next-generation formworks.
There are, however, the following problems with respect to plastic formworks. First, a unit price of the plastic formworks is about five times that of concrete panels. Secondly, initial investment for the plastic formworks is extensive. Furthermore, the investment cannot be amortized in one construction site.
As for costs considering a number of repeated use times, the first number of repeated use times of the concrete panels are normally about five, and the second number of repeated use times of the plastic formworks is about fifty, that is, ten times the first number. As for costs per one time use, which is obtained by dividing the unit prices by the numbers of repeated use times, the concrete panels are almost double the plastic formworks. The plastic formworks are superior to the concrete panels with respect to not only environmental load but also the cost per one time use.
However, since there is no means for effectively managing the long use time of the plastic formworks, the plastic formworks have not been practically and widely used yet.
The formworks are brought to a construction site to be built there. Next, concrete is cast between the built formworks to be cured, the concrete is hardened and solidified, and then the formworks are released. However, curing time remarkably differs according to portions of a structure to be built, such as a wall, a beam, and a floor, or the like.
There is no technical means for managing the formworks taking the differences of curing time caused by the portions where the formworks are used into consideration. Actually, a construction supervisor of the construction site and the men use the formworks on their hunches.
In short, it is impossible to solve the above problem with conventional plastic formworks and it is necessary to add a new function to the conventional plastic formworks. Furthermore, consideration must be done such that the added new function does not spoil the other functions of the plastic formworks. A technique that satisfies such requirement has not been known yet.
[Document 1] Japanese patent application Laid-open on No. 2004-332301