Why did you choose to compare cow and carabao specifically?

Both animals are ubiquitous in Philippine agricultural systems making a consistent stream of waste that has no use other than fertilisation. There is a research gap in comparing cow and carabao, and there is a research gap in using carabao manure in general.

Why did you select 10%, 15%, and 20% as your replacement ratios?

Previous research done by Millogo et. al., Fernando et. al., and sunusi et al. has found that 10 to 20% is the most efficient range, with anything higher often encountering reduced strength, higher porosity, and overall diminishing returns, and anything lower having too small of an effect to the point where it was almost indistinguishable from the control group.

How does this research address the identified research gaps in the Philippine context?

Prior to the study, there were three research gaps. First, no study has evaluated cow or carabao manure as clay reinforcement in the philippine context, where soil, climate, and building standards differ. Second, existing research typically examines only strength alone, or water alone, rather than both combined. Third, few studies quantify bacterial reduction using the aerobic plate count. All three of these research gaps are covered by our research study, and since all of our tests and evaluations are being done under Philippine conditions, our results will be able to fill the niches created by these research gaps.

Why have you chosen a 95% kaolinite + 5% bentonite clay blend?

Kaolinite provides good cohesion, plasticity, and overall strength, while Bentonite adding workability. We had to limit bentonite because previous studies have shown that adding too much leads to an unworkable mixture that absorbs all water, water that later evaporates and creates a level of porosity too high. 5% bentonite allows us to get the benefits without the setbacks, so we decided on a 95-5 ratio.

Why do lime stabilisation, and why for 21 days?

Lime stabilisation raises the pH level to 12, creating an alkaline environment that disrupts bacteria and denatures proteins, reducing microbial load. It also increases structural integrity by replacing weak ions with stronger calcium ions, reducing the thickness of the diffuse double layer, allowing particles to move closer together and form a denser, stronger structure.