make Lightweight Concrete Garden Boxes PART 3 - Aircrete Vermiculite Lava Rock

hi it's Kent from man about tools and today I'm making garden box panels from lightweight concrete [Music] this is part 3 of my series on casting your own reinforced concrete garden box panels these panels link together to make long lasting rot proof garden boxes in part one I made the forms from plywood in part two I simplified the design to make the forms easier to build and for this video I'll cast the panels with lightweight concrete I've had many viewer requests to make the panel's lighter so I did some research into this it turns out there are many ways to make lightweight concrete so to simplify things I decided to focus on just three formulations I wanted to use readily available materials that you could pick up at any big box building or a garden supply store or that you could easily order online for the first mix I substituted the gravel aggregate for lava rock in the second mix I use to find vermiculite and in the third I'll replace the sand and gravel aggregate for foam and try an air creat version of the garden panel I'll show the mixing pouring and unmolding and then look at the weight and durability results if you haven't watched part one in part two of this series then you might get more from this video if you watch them first there's a link in the upper-right or in the description below I'll be using the forms I built in part one in part two I have plans available on my website man about tools.com I also have a full blog post for this video with all the formulations ingredients and ratios for the concrete mixes I let all the test panels fully cure for a month keeping them damp and covered then I let them dry for a week or so before weighing okay so let's get on with it here's the first formulation so this will be my first attempt at making some lightweight concrete this blend uses Portland cement lava rock sand and some glass fibre for reinforcement you add about one pound of this fiber per cubic yard of concrete so when I calculated how much I needed per batch it came down to a third of an ounce per 48 inch panel so I just used a pinch so here's the proportions I used for the first attempt at lava concrete one part Portland cement three parts lava rock two parts sand and just a pinch of glass fiber these proportions are measured by volume I put the sand lava rock and fiber in the wheel barrel first and blended that before I added to Portland cement once that was well mixed I slowly added water I realized as I was doing this that it wasn't looking as smooth as I had wanted and it looked quite lumpy I thought well I'll go ahead with it and put it in the form I used a reciprocating saw without the blade to vibrate the form and settle the concrete mix then I laid in a piece of reinforcing wire mesh this galvanized wire mesh is cut from a large hog panel fence I bought from my local farm supply store then I topped up the rest of this and vibrated it some more I tried to smooth it out with a trowel and it wasn't coming out very well but in the bottom of the wheel barrel I had lots of sand mixture leftover so I just did the best I could with that for my second attempt I changed the ratio of it I went with one part Portland cement two parts lava rock and three parts sand and again a pinch of glass fiber I figured that I needed to add more sand to get a smoother mix so I started the same mixed it all up in the wheelbarrow and it came out a bit wetter than I liked so I added a bit more sand to absorb some of that water I could tell right away that this consistency was closer to regular concrete so same thing fill the mold halfway lay in the reinforcing wire grid and then vibrate and smooth it out I used a little bit of the extra mortar type mix in the bottom of the wheelbarrow to improve this surface finish on the first form and this seemed to work pretty well I covered the forms with plastic and left them to set up the next day I removed the formed sides and ends and these castings came out fairly easily I was pretty happy how the panel's looked but it could tell right away that they were a bit heavier than I expected I went back to our landscape supplier and got some lava rock that closely approximated gravel this red lava rock has a lot of smaller pieces instead of the same 3/4 inch size I compared the weight of gravel to lava rock for an equal volume the lava rock weighed approximately half that of the gravel for my third attempt with this more variable sized lava rock the mix I used is one part Portland three parts lava rock two parts sand and again a pinch of glass fiber I measured all the ingredients and mixed up a slightly larger batch again starting with lava rock the sand with fiber and then adding the Portland cement and then the water and into the forms as before it's settled nicely with vibration and all looked good the next day I remove the plastic and disassemble the forms these panels came out of the forms quite nicely and this was my final version of the lava rock mixture so as you saw I substituted the gravel for lava rock in this first lightweight concrete attempt the lava creat if you will worked very well once I used a variety of rock sizes that approximated gravel in my mix the finish is very good and the panel feels solid and durable this panel is approximately 10% lighter than regular concrete now that's not a lot lighter but I'd say it's almost equivalent in durability and strength I had hoped that this panel would be much lighter given that the lava rock was about half of the weight of the gravel I suspect that the voids in the lava rock were filled with sand cement and water during the mixing so I lost most of those air spaces that would have made it lighter okay so now let's look at the vermiculite mix so for this blend I picked up a bag of number three vermiculite it's a mineral that's expanded by heating in a furnace it looks a bit like mica the ingredients are Portland cement sand vermiculite and glass fibre I wetted the vermiculite slightly first before adding it to the sand in the wheelbarrow this makes it easier to blend for this first test is one part Portland cement two parts vermiculite and one part sand and is always a pinch of glass fiber this mixed easily in the wheelbarrow once it's well blended I had to Portland cement it felt quite dry and it took a bit more water than I expected and like before I fill the form halfway settle it a bit with the reciprocating saw add the mesh and then top it up and repeat on the other form and smooth the bubbles with a trowel and these are the vermiculite 36 inch panels coming out of the forms removing the sides and ends and then just gently prying the panel free with a paint scraper now the vermiculite blend mixed very well and felt much lighter even in the wheelbarrow and this made it easy to fill the forms it settled well with vibration and had a nice texture while troweling and edging it came out of the forms easily and it has a nice smooth finish it's noticeably lighter than regular concrete and I think it would be very durable as well it weighs on average 38 percent lighter than regular concrete now let's have a look at the air Crete the air Crete uses fewer ingredients Portland cement shampoo to create a foam and some glass fiber for extra strength so I begin by diluting the shampoo and water 15 fluid ounces of shampoo to two and a half gallons of water and this will be the dilution that I'll use to create the foam I stir this with a paint mixer attachment for my drill on a low setting just to dissolve the shampoo in the water I'll use suave daily clarifying shampoo as my foaming agent I'll use a digital scale to weigh my ingredients I use nine point four pounds of Portland cement five pounds of water one point five pounds of the shampoo dilution and a pinch of fiber I'm weighing the cement and to that I'll add a little handful of the fiber I then weigh the water and then I also weigh the shampoo dilution and it's three pounds to make my foam it's easier to make twice the foam I need I find it just mixes better I experimented with some different shape mixers to make my foam with wire I sowed some window screen onto this thin set or grout mixer when I tried to make the foam it's fun the entire mixture a bit too much so this one was a little too aggressive the next time I sewed the screen to a smaller egg beater type mixer I tried adding a little bit of stainless steel scrubbing pad to the center of it I don't think that really made a difference either way so this one worked better because it didn't spin the entire mixture it didn't cause it to overflow from the pail so I got a lot better results this way I'm using a five-gallon pail with three pounds of shampoo dilution so when the pail is full I get a foam density of 3 pounds per five gallons all you [Music] now with a paint mixer I'll add my Portland cement and fiber to the water a bit at a time I want to create a smooth Portland cement slurry so I add a bit spin it add a bit and spin it until it's smooth I also stirred them mixed by hand to make sure that there was no dried cement stuck to the edge or clumps in the bottom of the pail and this worked pretty well now the slurry is ready for the foam I add half the pail of foam to the cement slurry I'll use my mixer to blend it all evenly by hand stirred with an improvised stir stick to make sure that everything was blending right to the bottom of the pail and I got a nice even air creat mixture and this looked really good then I added the air creat to the form giving it a bit of a jiggle to help settle it into the corners and then I added a bit more to top it up I tried to get as close as I could to being full without over filling too much a little bit over is okay because the mix is going to settle and some of the bubbles are going to collapse then I can smooth it with a trowel and then lay in the pipe wrap wires and once it sets up a bit I gently lay in a galvanized wire reinforcing grid so it settles in right in the center and I made a couple more batches and filled a few more forms I was happy with how this was blending and how the grid was sitting in well I needed to push it into place so the air creat had enough density that I felt comfortable that the wire mesh was not going to sink all the way to the bottom of the form it was a hot day so I think that also helped the air creat to set up faster and I think that's quite desirable because then there's not as much time for the foam bubbles to pop when the air Crete was fully set up I covered the forms with plastic and left them for a couple of days I remove all the screws from the form gently pry off the sides remove it from the base and then remove the ends and I was really happy with how they looked they felt quite solid now this panel was the most fun to make and certainly the most unique of the options I tried I'd like to thank the honeydew carpenter and Eric Reed Harry for their many great videos on everything to do with air Crete I'll put a link to their channels in the description as well I was able to get a very dense foam without using a foam generator for my testing this worked well but if I was going to get into making a lot of air Crete I'd build her by a foam generator like the ones that Harry or Darwin use I followed air Crete Harry's formulation for what he referred to as a standard mix my air Crete held its shape and there was little if any bubble collapse as it was setting up the air crate panels came out of the forms well the surface finish looks pretty good and the bubbles looked uniform the panels were very light on average eighty percent lighter than regular concrete so wow that's pretty impressive but even after curing though I found the panels were not very durable there's no sand or gravel to add that impact or abrasion resistance I did a little test with all the panels by running a weed eater or lying trimmer against them not a scientific test by any means but something the panels may have to endure there was noticeable damage to the air creep panels but the others fared ok another bigger issue is what was happening to the air creep panels as they cured they were bending and cracking I suspect that with a lower strength in general the internal stresses caused by shrinking and drawing led to this bowling along its length and then these cracks forming this is what I think is happening anyways perhaps a mix with a greater ratio of cement to foam would prevent this it would bring the weight up a bit and there's still the durability issue if you've made these panels with air Crete or you know how to prevent this warping and cracking then leave me a comment below and then maybe I can get a chance to do a few more tests so I think for me of these three the best formulation for ease of mixing weight reduction and durability is that vermiculite blend if weight was an issue for my concrete panels I doubt for the vermiculite mix I'm not saying that the lava-rock mix are air creat are not worth trying because you might get better results than I did there's also lightweight concrete Ready Mix bags made by sac Reid but they're not available in my area so I was unable to test that so that might be a good option for you as well one last thing as I was doing these tests that came up with another way of making the panel's that's faster and lighter without sacrificing any strength or durability and that's coming right up in part four thank you so much for watching we'll see you next time I thanks for not falling asleep it's like watching paint dry sometimes I'm sure mixing concrete mixing concrete pour it in the forms let it set up and repeat okay see ya

Channel: MAN about TOOLS

Views: 264,641

Rating: 4.9327083 out of 5

Keywords: Lightweight Concrete, Aircrete, Foamcrete, Foam Concrete, Vermiculite, Lava, Lava Rock, Garden Box, Concrete Forms, Concrete Moulds, Concrete Molds, Reinforced Concrete, Gardening, Concrete Flower Boxes, DIY Garden Boxes, Garden Building, Garden Projects, Cast Concrete, Casting Concrete, Pouring Concrete, precast concrete, concrete planter, diy concrete planter, how to make a concrete planter, casting concrete molds, air crete, vermiculite concrete mix

Id: ddedMmuj7xY

Length: 18min 58sec (1138 seconds)

Published: Tue Jul 02 2019