Engaging in genuine scientific research is indeed something to be happy about, and achieving results is even more rewarding. Conducting reverse deductions when the conclusion is already known should be relatively easy.
Take the issue of the optical path, for example. Although he had forgotten all the optics he learned, he had genuinely studied it before. His calculus was quite good, so he should be able to derive the formulas again.
Back to the issue of cement.
He didn't know the specific composition of cement.
He knew that various clays harden once dried, and undoubtedly, concrete is the hardest when dry.
He tried mixing powders of various stones.
For instance, ordinary clay mixed with some powder indeed becomes harder.
As for how to improve its adhesive quality, he had no idea at all.
Anyway, he tried mixing all the powders he had on hand.
He could entirely melt sand, but he didn't know exactly what the purpose was.
