Awesome green paving and patching material

My lime sand mixture is going places, more awesome than I thought. So awesome that I think that's why you cannot buy hydrated lime in hardware stores, anything but.

In building supplies you can get 50 lb for less than $15. If you keep it dry and from air in a plastic trash bag, it will last forever. Sand is free. Now I have the habit of bring back from vacation a cup or two of sand, and immortalize them in my pavement or part of the house. Any cheap sand in hardware stores will do. Lime will dominate the color - brilliant white.

The new dry paving technique for gap filling. You just mix dry sand and hydrated lime (white power) together, and pour the mixture onto the gaps. Then you use a push boom, or small brush, to put the mixture neatly into the gaps only, and take away excess mixture. Then you spray water on the mixture with a spray bottle for example, enough to keep the mixture from blowing away by the wind, and not to much to avoid rinsing away the mixture. The next day you can pour water on it gently to finish the re-hydration process and start the recarbonate process.

The bad. There will be a brilliant white haze on the paving slabs. It will blind your eyes like snow if you live in sunny areas. I don't know how long will the haze be worn down by walking and the elements - basically it's lime stone if left for long. May be months or years. Certainly acid can cleanup the haze with little damage to the gaps. There is the biodegradable CLR. I have no idea how effective it will be. The white haze is a small price to pay.

The gaps will be brilliant white. Is it a good or bad thing compare to gray?

The mixture will take a long time to dry and harden. It doesn't matter for paving. You can walk right after as long as your slabs or stones are securely fixed. Light rain doesn't matter. It will probably heavy rain proof after a few hours. My gaps hasn't been hardened yet. Using the wet technique with water added into a paste, the mixture will harden like any other mortar, after days or weeks.

The good. This method is lighting fast. The mortar is permeable - the green way to go. For me that's a way to drain water away without having a level and flat pavement.

You can fill pretty large gaps economically and easily, as long as the lime mortar don't carry stress. It can be hard as limestone, but it takes a long time.

It's natural. Lime is from limestone, and will return to the limestone state gradually if left on it's own. It's non-toxic (but strong alkaline). It's safe for the environment, because it was the environment. I wash the tools confidently in the bathroom sink. There's the cancerous label but I think that's for breathing the dust in long term. Wear a mask and only mix it outdoors.

What is the lime and sand proportion? I have used pure lime. It shrinks and crack a lot when dry. It doesn't matter because no strength is required. The wet mixture in previous post is a guide. Basically, imagine the lime powder glue the sand particles together. So you just put enough lime in the mixture, but not too much.

You can use it on tiles, but they have to be horizontal.

Now for patching work. It has to be the wet mixture unless your holes and gaps are horizontal. Basically you mix lime with water into a thick paste without falling off walls. Then you add sand without too heavy on the mixture. The surface will be sand rough and permeable.

I have used the mortar for outdoor patching, to fill the cracks from ants entering. If not for the ants I'll leave it as it is anyway. So permeability is not a problem. If you have a base that is non-permeable, it doesn't matter. And you can always paint it with a non-permeable paint. You can always add some Portland cement to make it like concrete, but that's a complication. And you are better off buying ready mixed patches.