Bricks, Masonry, Asphalt and Concrete - Expansion Joints in Driveway

Not sure what the material is called but that fiberboard stuff between the concrete slabs is sunken down and now dirt fills and weeds grow out of it. Should I clean it out and caulk. (would take quite a bit) or expanding foam or what? Thanks.

I think you can just clean out the area real good and put in a new expansion joint.

I would clean them out and mix up a mixture of 1:1 portland/sand mix it to consistancy and pour in crack wait an hour or so and as soon as able to trile off trial it off level with the slab. It will have a different color at first since it will be new. Or before you do that get a pressure washer to clean the old slab down maybe even muratic acid clean it to a new finish and then do the filler.

I have the same problem with my expansion joints, but my neghbors use an epoxy to seal and it seems they are constantly making repairs. What can I purchase that lasts a long time with minimal maintenance? I remember seeing somewhere a black fiber board that expands and contracts. Anyone know where it can be purchased? Thank you.


Bosbury

The joints you are refering to are allow the separate sections of concrete to expand and contract according to the conditions. Concrete shrinks when it cools or dries out and does the opposite when it gets warm. The is also a long term shrinkage that takes place, but this is so small in a older driveway that it is not a factor.

You want a soft material to fill the joint so that the joint can shrink when the slabs expand. If you have a hard material there is no give when the slab expands. If you have something like epoxy is may case the edges of the concrete akong the joint to spall off. The same thing can happen if a open joint gets filled when as joint opens up as the concrete dries and/or cools.

The soft material prevents the joint from filling and allows the concrete to expand. You should replace the joint with the same material (cheapest) or you can try to find an adhesive caulk that will hold uo under the dirty, moist conditions in a driveway.

If you do try to replace the black joint material with a caulk, you will probably have to put a backing material (foam backer rod) in the joint to caulk against otherwise the caulk will not adhere to the concrete properly. Caulk sounds good, but the application is too difficult without experience in knowing how to do it and what to use.

It is best to replace what was there and periodically spray the joints with grass killer and ant killer.

Dick

Home Depot has an Asphalt inpregnated cane that works great and comes in 1/2 to 3/4 in width. Worked it into the gap works perfect. Thought I'd pass on the information. Thank you.