Materials & Techniques
Fresh Cow Dung
Extremely fresh cow dung should be collected within a few hours of settling. It should be wrapped in multiple bags to keep moisture content high and bacterial activity minimal. The dung should be used within 5 days of collection.
Medium Fresh Cow Dung
Cow dung collected within 14 days of settling is considered fresh. The dung will then be slightly dry, and there is no longer much of an odor. During collection, care should be taken to ensure the absence of worms and beetles.
Cow Dung Ash
The ash from burnt cow dung can also be considered an additive in the cement industry, as its chemical composition meets ASTM C150/C150M requirements for cement.
Cow dung ash consists primarily of SiO2, Al2O3, and Fe2O3, making it a pozzolanic material.
The addition of cow dung to cementitious materials extends the initial and final setting times of the mixed cement paste by 12%-59% and 3%-44%, respectively. Therefore, it can be used as a setting retarder in concrete work in hot weather.
Material Composition Guidelines
The composition of the materials varies greatly depending on the additives and the desired result. Since cow dung has not only waterproofing but also stabilizing properties, it is also used to make stabilized earth blocks.
According to Katale et al, 2014; Kulshreshtha et al, 2022; Worku et al, 2023*:
- Soil (depending on the soil type) mixed with cow dung has higher compressive strength but lower water resistance
- Sand mixed with cow dung has higher waterproofing properties but lower strength
Experience from Local Shit Plaster experiments:
- Clay acts as glue
- Larger amounts of Sand in base or first layer provide compressive strenght
- Larger amounts of Cow manure in last layer provide flexural strenght and waterproofing effect
Advantages of larger amounts of Cow manure:
- Reduces weight of the material - easier application
- Depth of color
- Higher waterproofability