Housing developers should consider using used nappies instead of sand to build homes.
That’s according to scientists from the University of Kitakyushu, Japan, whose Scientific Reports study suggests up to 8% of the sand in concrete and mortar used to make a single-storey house could be replaced with shredded used disposable nappies without significantly weakening their integrity.
The authors argue that disposable nappy waste could be used as a construction material for low-cost housing in low- and middle-income countries, in particular.
Disposable nappies are typically made from wood pulp, cotton, viscose rayon, and plastics such as polyester, polyethylene, and polypropylene – the majority of which are sent to landfill or incinerated once used.
The scientists’ research involved preparing concrete and mortar samples by combining washed, dried, and shredded disposable nappy waste with cement, sand, gravel, and water.
These samples were cured for 28 days.
The researchers tested six samples containing different proportions of diaper waste to assess how much pressure they could withstand without breaking.
They then calculated the maximum proportion of sand that could be replaced with disposable nappies in a range of building materials used to construct a house with a floor area of 36 sq. m. and which complies with Indonesian building standards.
The researchers found nappy waste could replace up to 10% of the sand needed for concrete used to form columns and beams in a typical three-storey house.
This proportion increased to 27% of sand needed for concrete columns and beams in a single-storey house.
Up to 40% of the sand needed for mortar in partition walls could be replaced with disposable nappies, compared with 9% of the sand in mortar for floors and garden paving, the researchers found.
Overall, the study found that up to 8% of the sand in all concrete and mortar building materials required to build a single-storey house with a floorplan of 36 sq. m. could be replaced with the waste from disposable nappies.
The researchers said: “The research also demonstrated that the mechanical properties and microbial content of disposable diaper concrete, in specific compositions, are identical to conventional concrete.
“Adding 1% diaper to concrete enhances internal curing hydration and produces the most robust, durable material.
“In addition, a mixture of up to 5% disposable diapers with concrete had the maximum strength at 28 days compared to other percentages.”
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