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Foundation for a mid sized power hammer

justin.mercier

Cast Iron
Joined
Apr 29, 2010
Location
Woonsocket RI
I need to re-arrange my shop to better fit the tools and machinery which I am trying to cram in there. As part of my plan, I am moving my 1902 Dupont Fairbanks model B (75 pound) power hammer to a position just between the doors of the garage. Since this is (IMO) the ideal location for it in the shop, I'm putting a proper foundation under it so that it can be used without rattling all the other machines in the garage.

I had originally planned on welding captured nuts in the bottoms of tubes, so that I could screw in bolts from above, but after welding the first nut to a plate, and finding the nut warped too much to screw 3/4" allthread into it anymore, I decided to just do it the tried and true way of drilling some 1" holes and epoxying in some 3/4" allthread to bolt it down. I hired a company to come in and cut out a hole in the 5" slab in the garage. I made a 3x4 hole, and dug it 2 feet deep, this should give me a total volume of ~0.9 yards of concrete. This should give me about 3600lbs of 5000psi concrete under the hammer, isolated from the rest of the floor. I've got some concrete isolation pad strips which will be placed between the existing 5" slab and the new slab as it's poured.

Unfortunately I called around and all the ready mix places near me have a 3 yard minimum, which means I'll have to fill the hole myself, because I dont want to pay for 3 yards and use just one =) Since I dont really want to mix fourty 80lb bags of concrete myself, I just bought myself a very inexpensive mini concrete mixer at harbor freight. I probably didn't even need any rebar for this project, but I figured that I might as well throw some in there anyways for good measure.

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powderhorn

Aluminum
Joined
Dec 22, 2009
Location
Southern Nevada
There was a book available from Centaur Forge that covered the Little Giant hammers, and it had a section on foundations for the various sized power hammers.
 

Andy FitzGibbon

Diamond
Joined
Sep 5, 2005
Location
Elkins WV
When dad did the foundation under his 100 lb. Williams-White, he dug down six feet, I believe. The W-W has a round base that's roughly six feet in diameter. None of this was based on any calculations, just a "that looks about right" sort of thought process.

Andy
 

enginebill

Stainless
Joined
Feb 17, 2005
Location
Plymouth Meeting PA
The best way to put in foundation bolts is to start with a nut and plate on the bottom of your foundation bolt. Then put PVC pipe down on top of the plate, use big enough pipe to allow plenty of room around the bolt, say 2" pipe over 3/4" bolt. Then put a template, to line up the bolts to your machine, over the bolts on top of the PVC and secure with nuts. Then set the top of the bolts where you need them and secure. Then pour the concrete. The pipe in the concrete will give you room in case the bolts end up slightly off.
 

JNieman

Titanium
Joined
Nov 12, 2011
Location
Greater St Louis Area
Those slots in the 5" slab for holding your square was a good idea. Shows some real planning and foresight! ;)

Looks good from here. I'm sure you'll be glad you put in that rebar though. It'll make a big difference in the cracking and what happens after it's spidered with cracks.. Never underestimate the steel! (or maybe my structural design background makes me overestimate it :) )
 

Joe in NH

Diamond
Joined
Jul 28, 2007
Location
Stratham, Cow Hampshire
Back at the hydro project, we had a contract requirement for 3" concrete cover over any rebar. But this may have been driven by the continual presence of water.

Also, tied joints between rebar had to be tied with at least three wires (three turns around.) No visible gaps.

Joints between rebar laid parallel had to be 30 diameters overlap with ties every 10 diameters (minimum 4 ties).

1/2 inch plywood works well as a spacer between the existing floor and the new foundation. It can be pulled out while the concrete is at that "touchy point" - or left until concrete full strength and then butchered out. Two layers of plastic might work well to help "glide" it out, but it makes for fussy work.

After removal of the plywood you then get the mastic out to fill the gap.

And of course you don't want to "add" to the bottom of the hole - always "subtract." You might even run some water into the hole a couple of times to settle and compact from the action of the shovel. In the power plants we had a pneumatic hammer with a tamper chisel (sounds like a misnomer) to get compaction - but we were always in a hurry.

Looks like fun work. I expect the concrete saw filled EVERYTHING in your garage with concrete dust. In the powerplant we cut a hole through an 18" concrete wall - the contractor had a 6 foot (!) concrete saw about the size of a towable compressor. We set him up with total tented enclosure - including airlock and negative pressure. A lot of concrete dust STILL got away.

Joe in NH
 

HUMPHREY MACHINE

Cast Iron
Joined
Aug 9, 2010
Location
ACTON MASSACHUSETTS
Great hammer Justin! I’d like to find just that model and size – love that it was made in Vermont! Your foundation looks great – like Joe and maybe others said – make sure that your soil in compact. Ideally you have dug down to undisturbed ground – IE soil that was not loosened or filled as part of the garage’s construction. I think that your use of rebar is wise if not imperative. As concrete takes time to completely cure – the longer you wait before placing and used your hammer – the better. Keeping it moist after it’s initial set also contributes to it’s strength.

Maybe the real question should be – ‘how is the foundation of your relationship with your neighbors?’ Just kidding really -- mine are set back a little more but I still worry about ‘disturbing the piece’ when and if I purchase a hammer. Thinking of a hydraulic forging press for heavier work and a 100lb or less mechanical hammer for the lighter.
 

justin.mercier

Cast Iron
Joined
Apr 29, 2010
Location
Woonsocket RI
I should have added, I cant cast the retaining bolts in place because of the clerance above the hammer in my garage. With the low ceiling beams, and my gantry crane just barely below them, I can only get about 3 inches of lift above the floor on the hammer, but in order to have thread above the base of the hammer which is 3 inches thick, I need about 5 inches of thread above the top of the concrete. This means I have to come down from above with any fastening system (hence why I was looking at captured nuts) Otherwise I would have done exactly what you are saying Engine Bill. In fact, that's what the original plans call for, a 1.5 inch hole around a 3/4" threaded rod for this machine.

The literature for this specific hammer called for a 2 foot x 3 foot concrete pad 18 inches thick, with wood on top of it, so I'm going a good bit larger than the 'suggested' size. I dont imagine that I'll ever have a larger hammer than my current one in the garage.... I dont think anything bigger would even fit !

There will be ~5 inches of concrete above the rebar, and similar distance around all the edges except at the front and back where it'll be closer.

I'm glad I hired out someone to come in with an industrial size saw to cut the slab, because even with a wet-saw keeping the dust down and whatnot, it was messy as heck. What took him 30 minutes would have probably taken me more than a week of demolition with concrete drills and sledge hammers and wedges, and wouldnt have nearly been as clean.

Now I just hope that the 5000psi quikreet bags dont "set" too fast, so that I can get 40 bags of the stuff mixxed and poured one bag at a time into that hole ! The project is just small enough it's not worth paying a ton extra for someone to come and pour, but just big enough that it's going to be a LOT of work to mix and pour that much by hand!
 

justin.mercier

Cast Iron
Joined
Apr 29, 2010
Location
Woonsocket RI
Maybe the real question should be – ‘how is the foundation of your relationship with your neighbors?’ Just kidding really -- mine are set back a little more but I still worry about ‘disturbing the piece’ when and if I purchase a hammer. Thinking of a hydraulic forging press for heavier work and a 100lb or less mechanical hammer for the lighter.

My neighbors are really close, one of the reasons I wanted an isolated foundation in the first place! The closest house is right near my garage, as you can see in the photos above, but it's been empty for 3 years now (I actually wanted to buy the neighboring house when I knew it was going for sale, but some bank bought it the day it went up on forclosure and they've been sitting on it empty for years now) On all other sides of me are garages and not houses, putting the next closest house at about 75 yards or more... still very close, so I dont use it except during the middle of the day =) I plan on giving it 3 to 4 weeks to cure before i move the hammer over the top of it, one of the reasons I want it done ASAP before we start getting hard freezes at night =)

Speaking of hydraulic forging presses... mine is on the freight truck being delivered to my house right now. I was going to build my own, but I've got so little shop time, and I'm a lousy welder, so I ordered one from Uncle Al Lawrence at Riverside Machine down south. Should probably arrive by the end of this week, if not by sometime next week. That's one of the reasons I need to move the hammer, the other is that I'm getting my first milling machine (Garvin No. 13) very soon as well, and need a place to put it. The press is probably going where the hammer is now, and the milling machine in the back corner, assuming I have enough space after moving some other stuff for the bed to travel.

The press will get more use than the hammer for sure, particularly for pattern welding, but there are some things that a hammer will do that a press just cant do well, so I wanted both.
 

Joe in NH

Diamond
Joined
Jul 28, 2007
Location
Stratham, Cow Hampshire
You could do as Engine Bill says, but instead of the allthread coming up out of the tube - use a "coupling nut" to provide a female hole you can then wind a regular bolt into. The top of the coupling nut will be level with the floor.

This will allow you to slide the hammer into place - have the "flexible" arrangement of EngineBill, and use of regular bolts. Once filled with grout, the action would be exactly the same as EBs description.

Coupling nuts in various sizes are available at McMaster. 90977A215 is the Grade 5 (3/4-10UNC) part number which won't hurt too bad.

Joe in NH
 

enginebill

Stainless
Joined
Feb 17, 2005
Location
Plymouth Meeting PA
Joe in NH has a good idea, also you could jack it up and roll it over the bolts. Or you could remove the jack shaft on top and mount the motor on the floor and drive the hammer with a flat belt. I have a nice 3/4 HP 3 phase 435 RPM motor that would work well for you. The last thing I would want to do is drill deep holes in concrete, that's too much like work.
 

Joe in NH

Diamond
Joined
Jul 28, 2007
Location
Stratham, Cow Hampshire
Joe in NH has a good idea, also you could jack it up and roll it over the bolts. Or you could remove the jack shaft on top and mount the motor on the floor and drive the hammer with a flat belt. I have a nice 3/4 HP 3 phase 435 RPM motor that would work well for you. The last thing I would want to do is drill deep holes in concrete, that's too much like work.

"Doublenut" or otherwise stake all the parts of a coupling nut anchor setup so they don't come undone during installation. Once the grout is poured and hardened, then you're probably set for life.

Joe K
 

justin.mercier

Cast Iron
Joined
Apr 29, 2010
Location
Woonsocket RI
I should probably have mentioned that the height problem is WITH the jackshaft removed =) the beams in my garage are only 8 feet 9 inches high. I can get my gantry crane set to 8 foot 6 at the top of the beam which means I'm hanging my chainfall from the trolly at about 7 feet high to the bottom of the hoist, and the hammer itself is a bit over 6 feet high.

I'll look into pouring the holes with allthread that's just flush with the top and using a coupling nut.

I actually plan to move the motor behind the machine mounted down low, and have planned the position of the pad accordingly so that I have space behind the hammer. I need to repair the brake (you can see the 2/3rds of the brake shoe that I do have + the counter weight for the brake in my first photo) and while I fix the break, I plan on fabricating the missing slack belt arm to mount on a pivot in the back of the machine. The threaded hole is there for the pivot, but the tensioner arm and pivot itself are MIA. I'll have to turn some wheels on the lathe to make an additional wheel with high sides.

The machine runs fine as it is currently, but without the break, and being a slack belt clutch, it tends to want to 'run-on' when you step off the treadle.
 

Joe in NH

Diamond
Joined
Jul 28, 2007
Location
Stratham, Cow Hampshire
If you can, get yourself a concrete vibrator for the job. The contractor used these in lengths up to 20 feet long for the hydroelectric dam and the quality it brings to the job in removing voids and bubbles is phenominal.

Some go around and beat on the forms with hammers - vibrators do the work much better, faster, and much easier both on the tools AND on the body.

At $99.99 (and you can find a 20 percent off coupon on the 'net) this Harbor Freight special is almost worth while.

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Be careful you don't get the vibrator hung up in the rebar - makes for very expensive reinforcement. At the dam, it happened once. The operator was told to cut the cord and throw the WHOLE vibrator in.

http://www.dealcatcher.com/harbor-freight-coupons

Joe K
 

Joe Michaels

Diamond
Joined
Apr 3, 2004
Location
Shandaken, NY, USA
As you say, you cannot lower the hammer onto anchor bolts due to limited headroom. Here is an idea which might work for your application: imbed tapped sleeves. Hilti offers these sleeves for use with resin grout. These sleeves are made of either carbon steel (zinc plated) or stainless ($$$). The sleeves have a coarse knurled surface on the outside to get a good mechanical bond in the resin grout. The tapped sleeves (or inserts) are often used when something has to be repeatedly removed from its location on a concrete slab (or wall), to avoid having to jack it up to clear anchor bolts. I've used these tapped inserts many times with resin grout for applications where equipment had to be unbolted and removed leaving a clear deck slab (we plugged the tappings with stainless set screws).

You can make these inserts yourself, allowing about 1/8" to 1/4" of total clearance between the OD of the insert and the ID of the holes in the concrete. If you google "Hilti" and drill down and muddle around, you will see these inserts.

In your application, I would suggest you make a bolting template out of wood to correspond to the base of your power hammer. Here is a method we used at the powerplant on this kind of work quite a number of times:

1. decide what type of resin grout you are going to us. Hilti sells quite a line of it, and some types are "gun mixed" with a spiral mixer tube (disposable, so you buy a pack). Calculate the volume of the tapped insert vs volume of the drilled holes and get the volume of resin you will need. Allow some overage, about 15-20%.


2. Screw short pieces of all thread rod with nuts into each of the tapped inserts.

3. By means of your calculations, you can get a fair idea of how deep to fill each hole with the resin BEFORE sticking the inserts in them. This prevents underfill or slopping too much resin out the tops of the holes. Some overflow is inevitable.
A 1/8" diameter rod with a piece of tape or collar as a dipstick is what we used.

4. Once you have the resin in a hole, you need to work fast as the stuff has a fairly short working time. This time varies with the ambient temp, so this time of year in Rhode Island, you may have a longer working time. With the resin in a hole, you stick in the insert on its piece of all thread and turn it a few turns and work it in the hole. This gets rid of any trapped air.

5. When you have all the inserts in the holes, you then set the wood bolting template down over the all thread studs sticking up from the inserts. Make up another set of nuts and washers just snug. Put a carpenter's level on the template and shim it as required to level it. This is your last chance to have anchor bolts coming up nice and square with the foundation.

7. After the resin grout has cured (there will be cure times furnished with the grout, but overnight at this time of year is a safe bet), strip the template. The foundation is now ready to receive your hammer.

As an aside, I am not one to set machinery, especially something like an engine ("unbalanced reciprocating forces at work"...) on the "neat line of concrete" (term for the surface of the concrete as screeded off or trowelled off to elevation).
To do so is to wind up with bearing on random points and this will lead to localized cracking of the concrete and movement of the hammer relative to the foundation. This is why a lot of machinery, turbine, and engine mainframes, bases or soleplates are grouted. The grout insures "full and complete bearing contact". You can accomplish this in a couple of ways:

1. If you do not want to go the route of grouting, you can use "Adhaesium Felt". This stuff is a heavy felt impregnated with a resin, and comes in a saturated roll, in a plastic pail. You take out what you need, cut to size with a box knife or snips, and make a bearing pad to match the base of your hammer. You then land the hammer on the Adheasium Felt, and insert studbolts in the tapped inserts. The nuts are drawn down snug. The weight of the hammer will compress the Adheasium Felt to take up any gaps or dips and dives between the hammer base and the foundation top surface. The Adhaesium resin sets up, and the hammer winds up bonded to the concrete. You then sock up on the anchor bolts. Adhaesium was used by us for indoor applications in dry locations to set machinery and some structural base plates. It is removable with hot water. Works quite well, based on my own experience using it in places where we did not want to start chipping concrete and using non-shrink grout. FlexBar should have the Adhaesium.

2. The traditional method is non shrink grouting. You will need to make an outline of the footprint of the hammer, adding perhaps 1/2" on each side. You then chip off the surface of the concrete to expose the aggregate and remove any of the slick surface finished concrete typically has. Chipping is done with air hammers, electric hammers, or by hand hammer and bull point chisel. Air or electric hammers are often used with a "bush tool"- a multi point steel which looks like a meat tenderizer. Either way, you need to expose the aggregate to get a good bond with the non shrink grout.

3. You then set the hammer and level it on steel shims. The shims also set a clearance for the grout under the base of the hammer. This is about 1" of space. On a hammer subject to impact loads and vibration, similar to a diesel engine, the ideal thing is to level the hammer with jacking screws tapped in the base. After the grout has set, the jacking screws are backed off. This makes the grout carry the whole load, no unequal support as would be the case if the jacking screws were left carrying load. I'd use square shims and try to use the minimum number to get things levelled. If you wind up with stack of lots of shims, this can act like a leaf spring in service. After levelling the hammer, tally up the shims in each stack and reduce it to a minimum by using thicker shims.

4. After shimming, you then make the decision as to whether to go with flowable grout or packed grout. either method works, but I think the flowable gives more of a guarantee of good bearing contact between the base and the grout. If you use flowable grout, the whole fancy name for it is "Cementitious, non shrink, non metallic flowable grout". Sonogrout works fine for the purpose, used it loads of times. Make a grout form out of lumber around the hammer base, and you will probably be instructed to soak the chipped surface of the concrete foundation top for 24 hours prior to grouting. The form can include a chamfered top edge and must be equal in height to the bottom surface of the hammer base plus perhaps 1/4". A pencil line inside the forms at the elevation of the hammer base's bottom surface is helpful. The finished grout must not extend above the bottom surface of the hammer base as it will only crack out if it encases the sides. The forms should be oiled with diesel fuel prior to assembling and closing them. For a small job, you can sit the forms on the concrete and seal them with something like "Duct Seal" (aka Dum Dum or Monkey S--t). Flowable grout lives up to its name, and you need tight forms. I've also held grout forms for small jobs like column or pipe support base plates to the concrete with silicon gasket eliminator.

5. Mix the grout in a wheelbarrow, per the grout maker's instructions for a flowable mix. Pour it in from one side of the foundation (you make need to get a large plastic funnel as a pouring funnel, or nail together a hopper type box on top of the forms). Rod the grout with a PLAIN steel rod to get work it in the form and make sure any air is removed. Do not use scrap rebar or all thread rod as this tends to work air into the grout. Rapping the forms with a claw hammer is also a way to settle the grout. Add grout carefully to make sure you are up to the bottom of the hammer. A little bit above the actual bottom, like maybe 1/8" is what I usually do to allow for any irregularities in an as-cast base or machinery frame.

6. When the grout has had its initial set, you can tool or cut the top surface to suit your ideas and eye using a patching trowel. The grout will have "stiffened up" to where you can cut it like you would butter. You can cut the top of the grout to a chamfer or cut it so it slopes slightly downhill from the hammer base to keep mill scale from accumulating there. On engines and turbines, we always cut the top surface of the grout so it ran downhill from the engine or turbine base. This let oil and water run right off.

7. Let the grout fully cure before you sock up on the anchor bolts. Most cementitious grouts will develop compressive strengths in excess of 5000 psi in 7 days, and be fully cured in 28 days.

If you have the bucks, you can also use an epoxy resin to set your hammer rather than the cementitious grout. An ideal product which will not only set the hammer for level but chock it against sidewards motion is "Chockfast Orange". This was formulated for setting ship's machinery and not only serves as a grout to provide full and complete bearing on the foundation (steel foundations aboard a ship), but also chocks the machinery so it will not move when the ship is pitching and rolling in heavy seas. We used Chockfast Orange on some hydro turbine work, and the stuff is quite amazing. Pricey, but with impact loadings such as a power hammer will produce, well worth the money. Philadelphia Resin produces Chockfast Orange and they have a whole line of epoxy resin machinery grouts.

Done a lot of engineering involving setting machinery and structural stuff on concrete, and putting in anchor bolts "after the fact". I believe the tapped inserts may be a good solution for your application, and the grouting on top of the foundation is something I strongly recommend.

Joe Michaels
 

justin.mercier

Cast Iron
Joined
Apr 29, 2010
Location
Woonsocket RI
I was going to pour concrete this weekend, but the concrete isn't going to get to my house until Monday now. I'll be mixing it up one bag at a time and pouring it in the hole.

Those Hilti inserts would be perfect, if they weren't so expensive. I cant justify spending more than 100$ just on the fasteners. This hole is already costing me waay too much money as it is =)

Single bag cement mixer is assembled and in the garage now, and longer hose to reach the garage with water purchased =P
 

justin.mercier

Cast Iron
Joined
Apr 29, 2010
Location
Woonsocket RI
I need the hose to get water to the garage, or i'll be walking several extra miles toal round trip to do 1 gallon of water at a time per 80lb bag. =) The water per bag on this is listed as no less than 2.8L no more than 4.7L most people I know who have used it say just about a gallon is right to be able to work it right.

I plan on filling the whole hole in one go, bag after bag after bag =P Volume wise, it should only take 37 bags, but i bought 50 so i'd have plenty of extra (have other projects that I can use whatever I dont need for this hole afterwards)

I'm going to look into one of those vibrator things from harbor freight possibly, because iv'e had several people both here and elsewhere tell me that with something as thick as I'm pouring that i should 'vibrate the concrete'
 

justin.mercier

Cast Iron
Joined
Apr 29, 2010
Location
Woonsocket RI
Do you think my hand compactor (10" square jobby) will do the job fine rather than a vibrator? Would save me buying or renting another tool. I haven't used my small mixer yet (just got it assembled!) so I'm not sure how long it takes to mix up an 80lb bag, but I'll do it as dry as I can then and still have the mixer turning it over and dumping it out. The mixer will be set up right on the edge of the hole so I'll be dumping right in the hole and not into a wheel barrow and shoveling out =)
 

Joe Michaels

Diamond
Joined
Apr 3, 2004
Location
Shandaken, NY, USA
Structural concrete was typically specified with a "slump" of about 3"-3 1/2". The batch plants had to qualify their "design mixes" before being approved to furnish concrete on the hydroelectric jobs I worked on. This meant lab tests of concrete cylinders for3 day, 7 day and 28 day strengths (compression tests), and submittals as to aggregate (source, type of stone, size of stone and sand-aka "fine aggregate"), and any admixtures such as plasticizers or for air entrainment. The slump is a function of how much water is added to the mix. The lab tests done to qualify the mix would include a set of strength vs water content curves. When the concrete arrived on site in the mixer trucks, it was often "batched out dry" if the batch plant was some distance from the site, or if there was a large pour and a chance the trucks would be standing around in a lineup to be offloaded. When the water was introduced to the dry mix, the time was noted as was the starting number of turns on the mixer bowl (barrel on the truck). After maybe 10 turns, we'd ask for a sample of the concrete. The concrete coming down the chute was very "stiff", and had to often be hooked down the chute with a shovel or hoe. About a wheelbarrow load of this first try was taken for the slump test. The slump test is kind of like a kid playing at the beach with an inverted sand-pail, making truncated cones out of compacted damp sand. The slump cone is a truncated steel cone, small end up, 12" tall. It has two handles on it. The concrete is placed into the cone with a scoop, about 1/3 of the way up, and the concrete is "rodded" with a round steel rod for a given number of shots. This is done for the next 2/3's of the cone's height. When the concrete on the last third is rodded it compacts down from the top of the cone. Concrete is then added to bring the concrete up above the top of the cone, at which point, it is struck off with a steel straightedge (a piece of cold rolled flat bar, usually). The cone is then carefully lifted straight up and away. The concrete contained within the steel cone "slumps". The cone is stood off to one side of the slumped concrete, and the distance from the top of the steel cone to the top of the pile of concrete is measured. This is the "slump". 3" slump is STIFF concrete. About 3 1/2" slump, which still has to be pulled down the chutes, is what was used for structural concrete when placed by chutes or with buckets (the kind that are picked with a crane and have a bottom dump gate). 3 1/2" slump means the concrete does not have a lot of water in it. It will develop very nearly maximum design strength and stands little chance of hairline surface cracking (as would happen if the concrete were too "loose" a mix with enough water for easy placing and making for a "slick" finish when steel trowelled). Air entrainment is another matter, and for structural concrete subjected to freeze-thaw cycling, 4 to 6% air entrainment makes the concrete a bit more resilient and less likely to crack from temperature cycling.

Plainly put, if the concrete is stiffer than chocolate chip cookie dough, it is has about enough water for structural work (foundations). If it flows down the chute and self-levels in the form (we used to call this "fresh cow s--t" concrete), it has too much water and will have curing cracks, as well as not developing the strength the stiffer mix would. Soupy concrete is used by homebuilders and similar, people pouring walkways or basement floor slabs and looking to get done quick. It is not what I'd make a machinery or structural foundation out of. When we built my house, I spec'd 3 1/2" slump, fc'=3000 psi minimum. I detailed the rebar and took cylinders for lab breaks.I wateched the concrete contractor like a hawk to be sure they did not run a load of cows--t concrete in.

Another archaic and very strong type of concrete construction was "Cyclopean". This is basically what the farmers did. It was used into the 1920's on low head dams. Cyclopean concrete is unreinforced. It is mixed in normal proportions as far as cement, sand, and crushed stone and water. However, large, clean boulders are laid into the concrete as it is placed in lifts. I worked a job on a hydro dam built in the 'teens. The original drawings were on hand, and they called for "Cyclopean concrete with 'man sized boulders' ". Farmers tended to throw creek cobbles into their concrete to save on the concrete, and plenty of barn and silo foundations and concrete milk can cooler tanks were poured using this kind of concrete. The other thing that was common on dams and critical concrete work years ago was the spec calling for "Rosendale Cement". This was a cement made from limestone mined at Rosendale, NY. It was said to be very nearly what the Romans had used, and was almost a hydraulic cement. Set up fast, little or no shrinkage, and very high strengths. Rosendale Cement would endure and tolerate weathering a lot better than Portland Cement. It also gave a much better bond. For many years, specs for bridges, dams, and similar work in the Northeast often called for a certain percentage of Rosendale Cement in each batch of concrete, the rest of the cement being Portland. I've worked on hydro jobs with concrete placed in 1910-1915, made with Rosendale cement. Between perpetual and near perfect curing conditions and Rosendale Cement, the concrete defied efforts to demolish portions of it. We had the contractors line-drilling with 100 lb air whirly drills (carbide drill bits), then trying to "pop" the concrete so it would split out on lines connecting the drilled holes. The popping was done using 90 lb air hammers with bull point chisels. A lot of bull points got wedged in the concrete, and a number of bull points got broken (this was before on site saw cutting of thick slabs was commonplace). The Roman concrete was legendary, and whatever the Romans used for mortar for laying stone masonry seems to have endured the tests of time and neglect. The joke was the NY City watershed dams, flow control structures and aqueducts were the rival of anything the Romans built, and the concrete- being made with the Rosendale cement- was believed to be as enduring.
 








 
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