enginear joe Posted April 12, 2015 Share Posted April 12, 2015 What if you insert foam rods or pipe insulation pieces from the bottom? Dow board slices? Something to create a lightweight filler in the middle of the pour? Can't help but nosing in! Quote Link to comment Share on other sites More sharing options...
enginear joe Posted April 12, 2015 Share Posted April 12, 2015 Wait! I got it! Insert a oiled pipe or two into the pour part way in. Remove the pipe later and fill with expanding foam! What do you think??? Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted April 12, 2015 Author Share Posted April 12, 2015 Yes that would work. I have thought of making a core of wire cut foam the shape of the viaduct only smaller in size and suspend it in the center like a core, and then pour as normal. I have also thought of making the top part with smaller sections, that would make it lighter to handle also. Good thoughts. I will have to think of something, my back isn't what it used to be. Perlite is a mineral, mined and then processed, cooked, and when it expands, that is Perlite. Lighter than anything else, except ground foam. If I make a core, the problem will be to keep it from floating when pouring the concrete, I will have to investigate how they do that. Bob. Quote Link to comment Share on other sites More sharing options...
enginear joe Posted April 12, 2015 Share Posted April 12, 2015 Thank you for listening! Perlite sounds just the same as Vermiculite then. I have to make a wire mesh core up here or the frost stresses will bust it! Suspend it with it bent outwards on the mold bottom or hanging from sticks maybe. Or just shove it in while pouring?? Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted April 12, 2015 Author Share Posted April 12, 2015 Vermiculite absorbs water, Perlite doesn't, so I don't think for concrete lightener you want vermiculite. Vermiculite is used for soil and planting, so is Perlite mixed with vermiculite. That is the way I understand it, also Perlite is pure white. Bob. Quote Link to comment Share on other sites More sharing options...
enginear joe Posted April 12, 2015 Share Posted April 12, 2015 Thank you! I have some kind of concrete recipes that were written for experimental lightweight concrete. They mention using several things and say that those two are interchangeable. I'm thinking by your description, that perlite maybe those little white rock things then I see in planting soil???? Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted April 13, 2015 Author Share Posted April 13, 2015 Engineer Joe, I think I am going with your idea of pipes inserted length wise in the top of the structure. Using 1 1/2 pvc pipe, 4 of them I could get the weight down to about 70 lbs. I can handle that. The pipes would be secured at each end through holes in the mold and the pipes would stay in. That weight is with regular concrete. I could further reduce the weight by using the perlite mix to about 50 lbs. So, thanks for your idea. Bob. PS. Yes the little white things in the mix is Perlite. Quote Link to comment Share on other sites More sharing options...
Jerry B44 Posted April 21, 2015 Share Posted April 21, 2015 I saw these concrete ideas on LSC. http://www.largescalecentral.com/forums/topic/23611/cement-signal-bases-all-about-that-base-no-treble Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted April 23, 2016 Author Share Posted April 23, 2016 Well, it has been a long time, but the viaduct molds are finally done. I am posting some pictures of them. I have been clearing the area in my back yard for the layout, had to buy a tractor and rebuild it and now it is a great asset. Hope to pour some viaducts in a couple of weeks. The only thing that is left is to spray with parting compound and I am ready to go. The total cost of making the molds, straight section and curved section, were about 2400.00, mostly the cost of the urethane. Bob. Quote Link to comment Share on other sites More sharing options...
enginear joe Posted April 23, 2016 Share Posted April 23, 2016 I don't know how U put up with all my interuptions, but thank you. It looks like you are going to have a first class RR. I wish I could buy some casts off U to offset your costs. Shipping would be expensive? I'd buy the rejects at this point. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted April 24, 2016 Author Share Posted April 24, 2016 What interruptions?, I don't remember any. Well, with the use of a proper vibrator, there shouldn't be any rejects, but I am always optimistic. As for selling castings, well, I had better finish my layout first before I think about selling parts. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted April 25, 2016 Author Share Posted April 25, 2016 I thought I would show you the lift that I will be using for the movement of the viaducts. Bob. Quote Link to comment Share on other sites More sharing options...
enginear joe Posted April 25, 2016 Share Posted April 25, 2016 Whoa, nice idea! I like anything that saves your back!! Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted April 26, 2016 Author Share Posted April 26, 2016 Yes, the sections will weigh 190, there is no way I can wrestle them around. I will be pouring directly into the molds, so that will save my back also. The hardest part will be to fill the mixer. Bob. Quote Link to comment Share on other sites More sharing options...
enginear joe Posted April 29, 2016 Share Posted April 29, 2016 I had to go back once more and read how much you spent on making the molds. WOW. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted May 1, 2016 Author Share Posted May 1, 2016 Yes, urethane is expensive, but very good. A 24 lb. kit costs 185.00, and a 120 lb. kit costs 685.00 plus the shipping. Ends up at around 740.00. You got me thinking about wearing out a mold, so, I might make a master part in case I have to pour new molds. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted May 3, 2016 Author Share Posted May 3, 2016 I guess that I lied. Here is the final stage of the mold. I thought that I would add some steel rebar for the transporting of the mold since I will be moving it before the full cure, so here is what it looks like. I have molded a space at each end for the rebar to protrude, so that when they are joined, they will be rigidly attached together with small pieces of rebar and concrete. Bob. Quote Link to comment Share on other sites More sharing options...
enginear joe Posted May 5, 2016 Share Posted May 5, 2016 Although there are lots of examples of concrete casting, I don't know of any guys who did this. I think the concept is great. It should be a lot easier leveling and maintaining these support pieces than every inch of track on ballast. I don't know what your yard conditions are. I would guess that this will make your life much easier when they're done. Quote Link to comment Share on other sites More sharing options...
Screwy Nick Posted August 22, 2017 Share Posted August 22, 2017 Bob, I finally found it, I guess I did't look hard enough. I'll now follow this one along with the T1. Thank You Quote Link to comment Share on other sites More sharing options...
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