Thank you. Sorry for the late reply.
The concrete road:
My methods:
1. I mixed the tile grout very heavily with moderate water to allow for quick drying.
2. I Spread it on the area of the diorama. I used grout (thick consistency). I did this outside, when the sun was out and let the heat dry the surface of the grout. As this dried quickly, it slowly produced the minuscule cracks you see.
3. Even it out with spreader.
4. Took a sponge and dabbed certain areas with it. I continued to sponge certain areas to give the grainy patches you see in a few of the photos
5. I used a small spreader to draw over the grout to produce some of the half broken concrete patches; sub-levels, and other small u level, rocky crevices you see..
6. Then I used a black wash and let that dried for a day. Then went over it again with the same black wash. Then let it dried for an hour, then went over it with a brown wash. I will go over it again, to knock back the brown again. Will post the complete diorama when done. Hope this helps those who are probably wondering how I achieved this results.
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The ramp was done using a mock-up cardboard, Then I poured mixed grout into the mock-up cardboard, and voila!
No plans for lighting. But I am working on another large diorama, almost similar which will be just over 2 meters long by 40cm.
Thank you.