What is Papercrete?
Papercrete is a sustainable green building material made by combining waste paper sludge from the recycled paper industry with Portland cement. The paper fibers act as reinforcement in the concrete mix, creating a lightweight and insulating concrete product.
Papercrete is an eco-friendly alternative to traditional concrete. It reduces landfill waste by reusing waste paper that would otherwise be discarded. It also requires less cement than regular concrete, reducing the embodied energy and carbon emissions associated with cement production.
Some key advantages of papercrete include:
- Sustainable – Reduces waste and uses less cement
- Lightweight – Weighs less than regular concrete
- Insulating – Provides good thermal mass and insulation
- Durable – Can be as strong as regular concrete when mixed properly
- Fire resistant – Does not easily burn or spread flames
- Low cost – Less expensive than traditional concrete
How is Papercrete Made?
The basic papercrete mixture contains the following ingredients:
- Recycled paper – The main ingredient, provides fiber reinforcement
- Portland cement – Binds the mixture together and provides strength
- Water – Hydrates the cement and forms the matrix
- Admixtures (optional) – Accelerators, plasticizer, fibers
The specific ratios can vary, but a good general papercrete mix is:
- 5 parts paper (by volume)
- 1 part Portland cement
- Enough water to achieve a moist, moldable consistency
The process for making papercrete involves:
- Shredding or pulping – The waste paper is shredded into small pieces.
- Mixing – The paper, cement, water and any admixtures are thoroughly mixed together.
- Pouring – The mix is poured into forms to create blocks, panels or other shapes.
- Curing – The papercrete is allowed to cure for 2-4 weeks to gain strength.
Proper mixing and consistent ratios are key to achieving good strength and durability. Compression strength can range from 100-400 psi depending on the mix.
Uses for Papercrete in Construction
Papercrete can be used for a variety of eco-friendly building applications:
- Papercrete blocks can be stacked like bricks to form structural walls.
- Panels can be precast then assembled into wall sections.
- It can be poured into forms like regular concrete walls.
- Low density papercrete makes an excellent insulating fill material for wall cavities.
- It provides good thermal mass to help regulate interior temperatures.
- Papercrete can be molded into decorative or artistic shapes.
- It is lighter and easier to work than regular concrete.
- Lightweight papercrete tiles can be formed for roof shingles.
- Can be sprayed onto roofs as a coating.
- A papercrete plaster can provide fireproofing for timbers and be used as a firewall.
- Can be hand-troweled into floors, then sealed with a protective coating.
Benefits of Building with Papercrete
Constructing with papercrete offers many benefits that make it an eco-friendly alternative to standard building materials:
- Sustainable – Reduces landfill waste and uses less cement
- Economical – Lower cost than concrete and utilizes recycled materials
- Energy efficiency – Provides good insulation and thermal mass
- Low carbon – Much less embodied energy than concrete
- Fire resistant – Does not burn easily and limits spread of flames
- Durable – Long lasting if properly mixed and cured
- Mold resistant – Alkaline nature prevents mold growth
- Lightweight – Easier to work with than concrete
- Versatile – Can be used for walls, sculpture, flooring, roofing, etc
Best Practices for Working with Papercrete
When working with papercrete for construction projects, following best practices will help achieve optimal results:
- Use the proper mix ratios – Test different mixes to optimize strength and workability.
- Shred paper finely – Smaller pieces hydrate and bond with cement better.
- Mix thoroughly – Blend for 5-10 minutes to distribute ingredients evenly.
- Keep mix consistent – Don’t add more water once batch is mixed.
- Compress well – Tamp blocks and press panels to improve density.
- Cure fully – Allow 4 weeks minimum to gain strength. Keep moist.
- Seal surfaces – Apply plasters or sealants to protect from moisture.
- Limit exposure – Avoid excessive rain/water exposure during curing.
- Get training – Take workshops if new to papercrete to learn proper techniques.
With some practice and experimentation, papercrete can be used to create affordable, sustainable green buildings. This innovative material is a simple way to reduce construction waste and build in an eco-friendly manner.