Everything You Need to Know About Hempcrete vs. Concrete

Hempcrete is increasingly gaining traction within the construction industry as a viable construction material and an alternative to the standard concrete.

It offers numerous benefits in terms of heat insulation, carbon absorption, and maintenance of a building’s structural integrity. While hempcrete and concrete share various characteristics, including their immunity to pest damage, these two building materials differ in many ways.

But before we take a look at these differences between hempcrete vs. concrete and their functional impacts, here’s how the materials manufactured.

Hempcrete vs. Concrete: How They Are Made

Hempcrete is made from a mix of hemp hurd, lime binder, and water. Hemp hurd, a hemp-plant by-product, is what is left behind after hemp fiber has been removed from the hemp stalk. The lime-based binder is used for coating the hemp shiv particles for extra strength.

The ensuing chemical reaction of the raw materials glues the mixture together in a process known as bonded cellulose insulation. The manufacturing process is completed by molding the hempcrete blocks and curing them in the open air for hardening.

Concrete, on the other hand, is made by mixing sand with gravel and crushed rock. Lime-based cement or hydraulic cement is then used as a binder. Structural concrete is made by combining specific proportions of cement, fine mineral aggregate, and coarse mineral aggregate. Aggregates are used to bolster the concrete’s structural performance.

After mixing the cement, water, and aggregates, the hardening process (known as hydration) begins. The longer the hydration, the stronger the concrete. The production of concrete is unsustainable as it’s estimated to release about 2.8 billion tons of carbon dioxide and consumes about a tenth of the world’s industrial water.

How Does Hempcrete Compare with Standard Concrete?

To help you make a reasonable choice, let’s compare these two building materials.

Environmental Impact

Unlike concrete production which has various negative environmental impacts such as carbon dioxide production, hempcrete is an eco-friendly material, both in its raw and completed form.

Concrete is also an air pollutant – construction workers are constantly exposed to concrete dust and this may put them at a higher risk of contracting respiratory diseases like silicosis.

Hempcrete, on the other hand, can store significant amounts of carbon dioxide, minimizing the greenhouse gas impact. Additionally, hempcrete doesn’t emit any harmful toxins into the atmosphere. The only negative environmental impact during the production of hempcrete comes from the carbon footprint generated from the process of making the lime-based binder, which can be controlled.

Weight of the Building Material

Concrete weighs about 6-8 times more than hempcrete. The latter’s lightweight nature makes it superior in terms of construction site safety, energy sustainability, and transportation costs.

Structural hempcrete blocks can easily be moved around the site without any risk of injury on the workers. Additionally, less weight means less embodied energy, allowing occupants of the building to significantly save on heating and cooling energy costs in the long run. The lightweight hempcrete is also easier and cheaper to transport to your construction site in comparison to concrete which is heavier.

Moisture Handling

Hempcrete boasts a porous structure that can absorb moisture from the environment. According to a research study, a cubic-meter of hempcrete can store up to 1314-pounds of moisture. This makes it a great option for buildings in highly humid regions. High indoor humidity can not only make living conditions unbearable but also promote the growth of mold.

Hempcrete floors and walls also contain lime which naturally contains antifungal properties thanks to its high pH levels. Unlike concrete, hempcrete keeps mold growth at bay.

Compressive Strength

Concrete has better compressive strength compared to hempcrete. Commercial concrete blocks have an average compressive strength of about 3000 psi which is made possible by its high density.

Hempcrete, on the other hand, has a compressive strength of between 72.5- 507.6 psi, which is about 17% that of regular concrete. Nevertheless, you can still achieve decent tensile strength with hempcrete by mixing hemp fibers into the hemp hurd, water, and binder mixture during the production process.

Availability

While hempcrete use has continued to gain traction over the years, it’s still difficult to find a nearby supplier. Contrarily, concrete suppliers can be located almost every few miles. However, this is expected to change in the future.

The 2018 Farm Bill legalized the cultivation of hemp in the U.S. As a result, you can expect the increased production of hempcrete and other hemp products in the market. With easy accessibility, the use of hempcrete is expected to skyrocket.

Improved Natural Disaster Resistance

Hempcrete offers better flexibility compared to concrete. Therefore, using structural hempcrete blocks for your building makes it more stable during seismic activities. This makes it a suitable building material for regions prone to earthquakes.

Hempcrete vs. Concrete: Bottom Line

Without a doubt, hempcrete is a more sustainable choice than concrete. As the world becomes more conscious about the environment, you can expect drastic laws and measures that aim to reduce pollution and the depletion of the earth’s resources. This means that different industrial sectors will be moving toward greener processes. When it comes to the construction industry, hempcrete is definitely the number one contender thanks to its environmentally-friendly production and application.

For any hempcrete-related questions or concerns, contact us for more information.

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