Concrete @ your Fingertips

Can you use lime instead of cement in concrete?

Lime concrete, often referred to as ‘Limecrete’, is a combination of natural hydraulic lime, aggregate and water. Limecrete is slow setting and does not gain strength in the same way as traditional Portland cement-based concrete.

It can be used for non-structural elements such as a domestic floor. However, a damp proof membrane will affect the breathability of the material and without a membrane there is a high risk of damp penetration. Limecrete is often used in conservation or historic building projects where moisture is not an issue.

Hydraulic lime must not be mixed with cement or cement combinations as this would negate the breathability of Limecrete, but hydraulic lime can be used in hydraulically bound mixtures (HBM) and soil stabilisation below heavy duty paving. Externally exposed reinforced concrete should be avoided and it should not be used with structural reinforcement as lime increases carbonation.

Limecrete is usually batched in small quantities using bags of lime with an on-site mixer. If a large quantity (several cubic metres or more) of limecrete is required, then this would need to be arranged with a ready-mixed/volumetric supplier as a bespoke product.

If considering the carbon footprint then it is important to note that the manufacture of lime releases CO₂ as does cement. However when mixed with water the CO₂ is reabsorbed over time as a recarbonation reaction.

For further detail on suitable applications and the types of lime available then it best to contact: https://britishlime.org/

Acknowledgement: ITE