Demolishing Concrete Wall

[centex]

Liquid Dynamite

This is interesting but they were talking about rocks which do not have rebar in them to keep them from cracking. I may try drilling some holes to see if it helps in breaking up the concrete. I believe it should help although I did not have any luck doing this in limestone when I was trying to drill fence post holes through it.

 

[Anonymous Poster]

Since the bridge is about 2-3 inches away from the wall, can you use feathers and wedges along the length of the wall and just knock it down that way? A bunch of hardwood wedges, a big pail of grease, a small sledge, and some patience probably would work.

 

[micromike]

I had a good size rock in the middle of an area where I was going to poor a slab floor for an addition. Had a similar problem as you. A friend suggested black powder. I drilled a series of holes in a line (they can be fairly small holes. I then drilled a one inch hole near the center of the line of smaller holes. I placed some cannon fuse in the hole and Packed black powder in with a wooden dowl. ( I don't want to insult anyones intelligence, but... please don't use a metal rod as they can cause a spark!) I then stuffed wadding (cotton rags) and then moist clay on top of that an inch or two deep to top off the hole. Lit the fuse and ran like heck. Actually, as it turned out I had plenty of time as the cannon fuse burned slow. Had some pretty good bangs and it did fracture the rock enough that with a pry bar we could break it up pretty easily.

Sometimes though it went off like a roman candle. Just kind of spewed sparks out the hole. Over time we learned to pack it better and had better success. We also learned if we placed dirt, clay and other weight on top of the area we were blasting it worked better to spead the blast down and out instead of just up. A tarp over that with more dirt heaped on helped contain the blast.

The normal cautions apply! I'm not suggesting anyone try this, especially if they don't know what they are doing. I'm just passing along what worked for me! /forums/images/graemlins/wink.gif

Mike

 

[Egon]

Many road construction blasting sites use mats made from discarded tires to cover the area and prevent debri from flying around.

Have you considered using some fertilizer as a helper?

What size black powder did you use?

Egon

 

[Egon]

Centex:

There are concrete hole cutters that will handle rebar. I'm not sure what size they go up to but the one I saw in use was a 12 inch diameter and could go througfh a 12 inch wall. They have a diamond toothed core bit that looks the same as a hole saw for wood or metal but without the center bit. This one used water for cooling and used hydraulics to advance it into the concrete.

Egon

 

[Anonymous Poster]

How about hiring someone with a trackhoe to pull it down and pile the chunks where you need the fill? Sounds like you could kill two birds with one stone that way. I'd use an acetylene torch to burn the rebar between the pieces of broken concrete if necessary.

 

[CTyler]

Ok.

There is a guy a couple miles up the road that has an entire walls made out of concrete plugs. They are all aprox 12-14" long and 8-10" around. He must have thousands of these things.

 

[RMulkey]

Centex,

I have not see anybody mention just renting a large backhoe (JD 710D) or excavator (JD 220LC) with a hydraulic breaker. I have used a 710D with a breaker to remove several solid granite bolders the size of semi trucks without much trouble. In central CA, it costs$450 per day for the larger BH and breaker plus $70 delivery. The Excavator is $1100 per day with the breaker.The BH should be fine for this size job. Depending on what creek bottom, you may be able to drive to the site in the creek.

For about the same price you can hire someone to do the work as long as the waste material can stay on site, , but what fun would that be.. Then again, how often to you get a valid reason to use explosives. /forums/images/graemlins/ooo.gif

 

[wroughtn_harv]

Morning Don,

The water factor does compromise most of my normal responses to such a beast. I like electric chipping hammers.

I suggest first changing the situation from a single big problem into a series of small problems. I would do this with a good concrete saw. I have a Stihl570 or some such with a diamond blade and it loves concrete.

I'd start by making a vertical cut as deep as the blade will go about ten to twelve inches in from one end. I'd do the cut about two feet in length. I'd then stand on top of the wall and swing my twenty two pound sledge, just a time or two would be my guess.

I'd repeat this process across the top. When I had the wall two feet shorter I'd start all over again.

Another option is renting a hydraulic power source if your tractor doesn't have the auxillary ports to run a hydraulic jackhammer and saw.

They have hydraulic jack hammers. The last time I priced one they were about twenty five hundred dollars while a pneumatic one was less than a grand.

You could also rent a hundred cfm compressor with a rotary hammer and a sixty pound chipping hammer. You'd need extra hose but that wouldn't hurt the effeciency of the tools. If you did it on a long weekend you're looking at three or four hundred dollars and a ton of fun.

With the rotary hammer you could drill vertical holes destroying the integrity of the wall. Then with the chipping hammer you could take advantage of the moment. /forums/images/graemlins/grin.gif

 

[Anonymous Poster]

I'm confused on some things here.

You want to remove the concrete, but you want to fill in the washout first - won't it just wash out again? You need to get rid of the concrete first, and then fill in the washout????

You keep saying you can't get any kind of power or tractor to the bridge. Most of the time one can drive in the bottom of a creekbed. Have you considered this?

Also, why can't you drive onto the bridge from the other side? Are you saying both sides are washed out?

Sure would hire someone to break it out if it were me, that's the job that needs to be done first, get it done & then deal with the rest of the issues as I could. But you need the water flowing right as a fist step.

So, where did the other owner expect the water to go, didn't he make a spillway & all that? Sheez.

--->Paul