why rough concrete pavement?

[billsstamps]

Here is a photo I took today of a pavement surfaced with rough concrete and a few neat tiles in the middle.
Why? I wondered.

It is outside our hotel in Hong Kong and Democracy protesters dug up the tiles to throw at police. Then the council hastily resurfaced with concrete

[HerMajesty]

Faster repair than tiling, and prevents a repeat of thrown tiles? Do you know the reason? Interesting times. I'm a bit surprised the protests have gone on so long, and wonder if the violence is actually always caused by the people wanting the positive changes.