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/