Diapers are highly challenging waste to recycle due to their slow and complicated degradation caused by their high plastic content. In addition, they constitute a significant proportion of the waste generated daily worldwide. However, a solution has been discovered to give them a second use and prevent them from ending up in landfills. At Kitakyushu University, Japan, a group of researchers has successfully carried out a trial involving the use of disposable diapers as part of the raw material for the production of concrete.
Concrete with disposable diapers as raw material.
The test proved successful. They tested the new concrete by building a 36-square-meter dwelling. The conclusions of the work were published in the journal Scientific Reports.
The construction materials used in the low-cost housing have a composition of 10 % of recycled diapers in their structural components. While in the concrete used in the non-structural ones, the waste reaches 40 %. The study revealed that 1.73 cubic meters of recycled diapers were used in the 36-square-meter house.
The preparation of the concrete is very simple, the formula they apply is achieved after making several tests, replacing sand, a fundamental raw material for making concrete, with shredded diapers. The tests carried out concluded that they can replace between 9 and 40% of the sand. It should be noted that this does not affect the structural strength of the construction.
Step by step of the diaper recycling process.
By analyzing the composition of disposable diapers, we can appreciate the ingenious conception of scientists. These diapers are composed of highly absorbent materials such as wood pulp, cotton and polymers. These components have demonstrated their ability to improve the properties of concrete, which is beneficial in applications such as road construction.
In order to conduct the study, the scientists collected diapers and meticulously washed and dried them. They then shredded them and incorporated them into a mixture composed of cement, gravel, sand and water. They then created different mortars using different percentages of shredded diapers in order to determine the optimal mixture capable of resisting the pressures required in construction. After a month, they subjected the different mixtures to different pressure tests.
The discovery is a coup for ecology
The resulting concrete is used only for houses up to a maximum of three floors. This means that, according to calculations, shredded diapers can replace 27 % of the sand needed in a low-cost single-storey house.
In addition to lower costs, the study has other implications. 8 % of the planet’s CO₂ pollutant emissions come from the cement industry. For their part, diapers account for more than 5 % of non-recyclable household waste. A diaper, in nature, takes about 500 years to degrade. In Spain alone, around 1 billion disposable diapers are used every year. This is equivalent to more than 170,000 tons of non-recyclable waste.