For our master thesis, we are looking for concrete compositions and optimisation of concrete properties to be able to grow mosses on concrete.
We made a mortar composition with blast furnace slag and one with repair mortar (with MgO).
We know that we need a low ph, a high porosity and a high surface roughness to enlarge bio-receptivity.
Does someone know which steps we can take in order to do so?
I think you should go for No-fines concrete with some amount of fly ash after making no fines concrete and sprinkling fly ash in pores which can provide micronutrients for growth of mosses and will also prevent quick drain out of water.
The pH of the concrete can be lowered to 11 by replacing some of the cement with fillers such as fly ash. At this pH it is difficult to maintain conditions for mosses to grow. It may be appropriate to add a small amount of foaming agent to the concrete to provide sufficient pores in which organic matter will collect to provide food for the microorganisms. Another way is to make a cement slurry with a high water to cement ratio. Once the grout has set and the water has evaporated, a porous structure should form, especially in the surface layers. Concrete reduces its pH with age due to carbonation. It is therefore also possible to try to accelerate this process or to take near-surface samples of old, carbonated concrete for testing.
- Badges
- Science topic