G Scale Model Train Forum banner

1 - 19 of 19 Posts

·
Premium Member
Joined
·
631 Posts
Discussion Starter · #1 ·
The Death of a Concrete Building

This story of the deterioration of my barn should NOT be construed as a rant or “bashing” of the Jigstone product. I want to make it absolutely clear that the fault of deterioration is not in the molds that are sold as Jigstone. The problem IS the “so called” anchoring cement. This story is similar to the “I wish I would have known” series at the back page of Garden Railways magazine. More discussion on cement at the end of this story. Yes, this building was constructed using Jigstones.

As the building began to deteriorate, I ask myself “How old is this buildings? Well, I built it about 10 years ago….. WRONG! It was in the year 1767. How do I know? …because of the time machine. The one determined by scale. (I know some of you have “fast clocks to determine the speed of your trains). So… say I work at 1:24; well that means there are 24 days in one real day? Do I have that right? Then that means in 10 real years there are 240 scale years. 2007-240= 1767. I never really thought about it that way.

Well here are some photos of the barn that I built in 1997 using Jigstones and Quikrete Anchoring Cement in the little yellow buckets. This barn won Best In Show at a SouthEastern Garden Railroad regional convention in 1998. It is featured in the Jigstone Newsletter from 1998. It was a combination of Jigstones and sheets poured on Precision Products plastic sheets. The roof, doors, shutters, louvers, and wood siding are all poured on Precision Products sheets. These did not seem to fail.

http://www.jigstones.com/newsletters/newsletter-pages/v1n03.html

In the eventual collapse on or about July 20th, the faithful horse which waited patiently at the stable door, died under the debris. The adjacent shed for equipment deteriorated many years ago. Railroad equipment will be brought in next week on the adjacent right of way to remove the debris before it becomes a fire and safety hazard.

The first photo is from 1815 (1999) when the Pennsylvania Stone Bank Barn was established on the farm prior to the railroads existence.



The second is a closer shot showing the stable in the lower portion.



The third shot shows the front and the beginning of the railroad in 1839 (2000). Shortly, thereafter the stone walls of equipment shed collapsed.



The fourth shot shows the detail of the side with surveyor tape in the background for the railroad.



The walls below grade were completely waterproofed with commercial 40 mil peel & stick fully adhered membrane. By 1869 (2001), the foundation had completely deteriorated. The rotten part was cut away sealed and replaced with 2 x 2 pressure treated wood.



The barn served many fruitful (no pun intended) years providing agricultural products to the community. Here it is shown at its peak in circa.1935 (2004).



Several major blizzards hit the farm in 1940's and 1950's. (2005).





By the 1960's and 1970's (2006) cracks formed in the end walls.





Somewhere in the 1980's and 1990's the walls began to fall out.





Finally, in the new millennium as they called it, the entire structure collapsed and killed the horse. Farmer Joe escaped and managed to save his tractor.




The general deterioration shown on my barn is IMHO caused by the gypsum contained in anchoring cement. “Anchoring Cement” is a BAD term for the troubling cement product and must have been created by some marketing department. Little do they know the term does bring with it an implied warranty of “fitness for use intended.” Several years ago I questioned one of the major manufactures, which was selling an interior (anchoring cement) product to the big box stores. This anchoring cement indicated that it required a sealer in order to be used in areas subject to water or moisture, e.g. exterior use. This sealer wasn’t sold at the big box stores. I questioned the liability of someone using it for an exterior railing. Suddenly, it seemed that some big box stores no longer sold this product.

As you may be aware, cement shrinks as it cures. This is sometimes referred to as “creep.” When it comes to grouting or anchoring, there is a need to offset this shrinkage by creating a form of expansion. This is why they call some grouts “non-shrink” type. This is why many companies add gypsum. They may also contain chlorides, nitrates, sulfides, and sulfates. The problem is gypsum, re-hydrates after it is dry when it gets wet again or re-absorbs moisture. This is what causes the deterioration.

Thus, I have come to rely on more “professional” products known as “non-shrink grout,” for structural purposes. Meeting ASTM (formally known as American Society for Testing and Materials) C-1107, Standard Specification for Packaged Dry, Hydraulic Cement Grout (Non-Shrink). Some of the brand names are Bonsal American/ ProSpec/ Sakrete/ Old Castle F-77; Quikrete Precision Grout; or Degaussa/ Sonneborn. Most of these grouts have a compressive strength in excess of 6,000 pounds per square inch or better at 28 days. The standard only requires 5,000 psi. Also, Grade B, post hardening would be preferred if a “grade” is indicated.

These types of products have worked well on several other projects which have been outside for 6 or 7 years. I have grouted the rocks of my 16 foot waterfalls and made tunnel portals with this better “grout.”

As a side note; these grouts come in 50 pound bags as opposed to a cute 5 pound yellow bucket. The price of a 5 pound bucket used to be $6 or about $1.25 per pound; whereas the bag of grout runs about $15 to $20 or 40 cents per pound for better cement. I realize that 50 pounds of cement is a lot but it will fit in a 5 gallon plastic bucket to prevent it from absorbing moisture.

For casting purposes, I would not recommend other types of cements or pre-mixed concrete. Mortars and some premixed cements are cheaper ($3 to $5) because they contain significant amounts of sand and gravel. They also usually come in 60 to 80 pound bags.

I would recommend planning several projects together to utilize the cement. Try some tunnel portals, bridge abutments, a few building walls, and roofs. ½ inch square hardware cloth (mesh) is the perfect reinforcement.

Have fun casting in concrete, but be careful of what you use.
 

·
Registered
Joined
·
144 Posts
That was a beautiful barn, very faithful to its prototype. Have you plans to make another? It's a shame to see it gone. And many thanks for the info on grout and cement!
SandyR
 

·
Premium Member
Joined
·
687 Posts
My thanks to Richard for sharing his experience ...

While I have had some success in using anchor cement, there is no doubt that it requires some care in its placement and lots of maintenance - it will never last as long as the kinds of products that Richard has spoken of.

Jigstones are a very good way to duplicate masonry structures. But as with all methods, we have to be aware of the weaknesses as well as the strengths.

Regards ... Doug
 

·
Premium Member
Joined
·
4,716 Posts
Ooh!

Perhaps I'd stick to casting resin.

I wonder what Jan Golding uses on hers.
 

·
Premium Member
Joined
·
2,007 Posts
Too bad, that was one sweet looking structure.
BTW, buying large amounts of concrete for a small project is not a good idea, unless you haver several projects (as Richard mentioned) because the concrete goes bad after a few months and won't harden properly. So, if you're buying 50lbs you better make sure you either use it all up or throw the remainder away. I know you hinted at this Richard, but I thought it might be helpful explain why you want to use it all up for those that aren't sure.
 

·
Premium Member
Joined
·
937 Posts
No No No....Leave it just like it is. I've seen a lot of old limestone barns collapse here in Kansas, it's a sad thing, but it's part of the life of an old farm building. That last picture looks exactly right. Make a story up of why it has collapsed and leave it on your railroad. After all, the world is not full of pristine buildings.
 

·
Premium Member
Joined
·
631 Posts
Discussion Starter · #10 ·
Thanks for the nice compliments. Yes, I will make another barn, and there is some salvage there. The panel castings such as the roof and front and back wall are still pretty much in tack. I may rebuild the end walls similar to the round house by carving Styrofoam and then making a latex mold. The panel casting allows for reinforcing. Some of today's concrete is reinforced with fibers. I wonder how that would work with the Jigstone castings. I did leave it collapsed for more than a year. The light colored cement (almost white) sort of spoiled the derelict appearance.
Richard is correct; cement can't be stored for a long period; but at $15 it is equivalent to 2 yellow buckets. Heck, put some aluminum foil in a mulch pile and make rock castings. I think the reason they suggest anchoring cement is for its rapid set. After all you can't wait a day to cast 2 more jigstones. It might take a year to cast enough. Doug is absolutely right about knowing the limitations and making provisions to accommodate it. If using the anchoring cement then each stone should be sealed before assembly. May be even dip them in a sealer. The joints also need to be well grouted and sealed to keep moisture from getting in between the stones and freezing. Better yet, bring it in during the winter.
Several people ask me how long I leave the kids out in the snow. I said ...."Until they get tired."
 

·
Premium Member
Joined
·
2,093 Posts
Posted By Richard Weatherby on 08/01/2008 7:51 PM
I may rebuild the end walls similar to the round house by carving Styrofoam...


Try using Precision Board to carve your rock sides. I just completed a four hour class in how to build buildings from this material and it may be JUST what you need. I've posted several times on here with photos of buildings made from PB. When it's sealed before painting, it's damn near imprevious to weather from what I can see.

PB is a foam material made for use by sign companies...it's machinable, carvable, distressable, and waterproof. You carve it with a dremel tool to make it look like rock. You brush it with a wire brush to make it look like wood. You glue it together with urethane glue. Dissimilar material is glued to it using silicon glue (Silastic).

The sealer is to keep UV from degrading it. Here's a photo I got from Tom Rey (reylroad here) of a farmhouse he built from wood...and an identical one from PB. BOTH are three years old...and both were in the same location on his layout.

You can buy sheet Precision Board from Rainbow Ridge.

http://www.rainbowridgekits.com/PrecisionBoardSheet.htm.

It comes plain (for rocks you carve) and shiplap (for shake roofs). There are brick, block, board & batten styles too.

Try it. I think you'll like it. It's quite structural. I'd being interested in how well it stands up in the cold climates like you have in MD. It sure does fine here in the hot area.
 

·
Premium Member
Joined
·
2,007 Posts
This post has been both fascinating and a little frightening. That deterioration sure happened fast.


10 years is really a long time for anything to last out of doors with no maintenance. I like that Richard scaled it down to show how many years the structure really lasted. 240 years!
When I was a carpenter I did a lot of section 1 work (thats what we used to call structures ruined by termites or water here in CA). I've seen structures only 50 years old with concrete paremeter foundations that are literal falling apart like stale bread because the original builder used beach sand in his mix and the salt content was too high.
Even 10 year old or newer foundations destroyed by root intrusion, errossion, earth quakes and/or floods. If it can happen that quickly in the real world, think how fast it could occur in a scale world using Richard's formula!
 

·
Registered
Joined
·
124 Posts
I'm wondering if the concrete/gout fell apart because of freeze-thaw cycles.
Concrete used in cold climates will be air entrained. Admixtures are used so that tiny air
bubbles are created during mixing. The bubbles allow space for water to expand into ice
with out cracking. I'm wondering this was some of the issue.

Compressive strength is not always the most important factor. Durability
is often equally important. I would say the biggest factor is strength
is the ratio of water to cement. Less water gives stronger concrete
but the concrete needs to be workable.

On bridges it is critical that after the concrete is cured, that is be sealed with a water proofing
solution. This is probably more to resist road salt. But a sealer may help.

Is or could a mesh reinforment be used when casting these?
 

·
Premium Member
Joined
·
631 Posts
Discussion Starter · #16 ·
Chris;

Your observations about concrete are correct. However I think in this case grout is a bit different. These materials are generally a lot soupier and do not necessarily utilize water reducers, plasticizers, or aire entrainment. I agree that compresive strength is not a factor but products with high compressive strength seem to have significantly less water absorption. I can only say that I do have other cast items which have lasted for years without any evidence of deterioration. Yes, the roof of the barn had a hardner and sealer. It work fairly well and prevented the paint from adhering or staying on more than a year. You are correct about the sealers on bridges. They are there to keep the chloride ions (salt) away from the steel reinforcement which can corrode and pop or crack the concrete. The joints between the stone modules are also a vunerable space for water to enter and freeze. The stones were glued together with liquid nails and grouted. I will see if I can post some photos of cement that has held up well. This post was intended to discuss the anchoring cement and the deterioration over 10 years. Like I said the building lasted 240 years.
 

·
Premium Member
Joined
·
687 Posts
Richard

Over the course of this coming winter, OVGRS members will likely have a go at building two or three more Jigstone buildings using your recommended materials.

This building activity is likely to mean that our molds (we have collectively many sets) which have already cast perhaps 2,000 stones each will be used to cast another 1,000 each. Can you comment on your experience of how well the molds stand up to usage?

Regards ... Doug
 

·
Premium Member
Joined
·
631 Posts
Discussion Starter · #18 ·
Doug

You guys have cast far more stones than I have ever cast. To be prefectly honest, I have not cast any Jigstones with the new grout materials; but I have cast tunnel portals and grouted the waterfalls. Like a said above, I am not sure what affect the cure time will have on casting individual stones. I do not have experience with how long it will take for the grout to cure in the molds. The grout material did not have any adverse effect on the latex mold that I made for the tunnel portals.

At one point, years ago, I did do a freeze/thaw test by soaking them and freezing them and baking them in multiple 3 hour cycles between the sink, the freezer, and the oven. My wife thought it was stupid. No failures after 5 cycles, I think.

To make a long story short, I am now taking the approach to protect the structures from the significant amounts of rain and snow. I am currently not constructing with concrete, but trying wood, metal, and foam.
 

·
Registered
Joined
·
124 Posts
It would be interesting to experiment with some concrete mixes
for casting. I remember Class AA mixes that use a 3/8" minus
aggregates. The weights of the aggregates, sand, type ll cement and
water would have to be scale out a 1 CY mix. Admixtures would be tough
unless a batch plant would give you some.
Low water cement ratio, replace some of the cement with silica fume,
target of 3 to 5 percent entrained air,start with a 1 inch slump then add super plasticizer to bring it up to 5 to 7 in.
cast them and cover with wet burlap and poly sheeting. Then the next day strp the forms and 70 degree water cure for 7 days.
 
1 - 19 of 19 Posts
Top