Frost damage to indian paving - Problems with indian

[Dave_L]

Is it possible that this is a combination of extraordinary porous sandstone (poorer quality) allowing excessive moisture in to the substrate, which when frozen, creates ice within the substrate, expands, and causes the noticed movement. It has to be extraeneous, as the coefficient of expansion for the substrate in any other condition is going to be extremely small.

haha I love the big words but I reckon that statement hits the nail on the head.

[topgrafter2007]

its good to get feed back guys so thanx! ive got slight probs with 3 drives now 2x had indian paved panels ov various sizes set into them the other is all indian supplied by the customer. on the drives with the indian panels only the indian areas are affected all other concrete flags are fine! drives weve done over previous years are fine. sooo.... im convinced its the indian thats the root cause of the issue. guess with money tight the quality of the imported paving has plummeted combined with horrendous weather. and now IM paying the price! will have to get someone to help me with the big words though :;):

[Tony McC]

Billy, with his allegedly 'big words' may well be right about the sandstone being particularly porous, and combined with the recent weather, which has been worse than we've become accustomed to over the last few years, could perhaps explain the problem. But you're in Blackpool, and I know from experience that when the rest of the country is frozen solid, the towns of the Lancashire cost remain just that little bit warmer.

I had gangs on jobs in Wigan or Preston where work was stopped because the ground was frozen, while projects in Southport or Knott End were positively basking at a balmy +1C, with no frost and no hold up to work.

I still suspect the laying course is at the root of the problem, though. The sandstone may have contributed, as seems to be evidenced by the different outcome for the concrete and stone paving, but there is no way stone can expand and contract without incurring blindingly apparent delamination.

It's be fairly easy to test this theory. Get an empty plastic pop bottle, one of the 1 or 2 litre sorts. Cut off the shoulders and cap to create a cylindrical container with an open top. Get some of the suspect 'sand', saturate it with clean water and allow it to drain until water stops running from it and then bang it into the pop bottle to about 100-150mm depth. Pack it down to replicate compaction under a flag. No water should appear at the compacted surface: if any does, drain it off.

On the outside of the pop bottle, mark the level of the compacted sand, and then put it in the freezer. leave it for a couple of days and then take it out to see if the sand has actually expanded when frozen.

Let us know how you get on....

[Dave_L]

Good idea there Tony, good thinkin'

[topgrafter2007]

your right what you say tony about it being slightly warmer here on the coast, but we had regular minus -3 & -6s. though no snow as such. will give your test a go over the next week or so. im just trying to get to the bottom of the issue as the job were it was, was a drive in all indian and has the main issue and the customer wants it putting right by me at my cost even though we only supplied the labour! and laid the drive in same way as we always have. as usual the customer thinks it all my fault despite me trying to explain to the best of my ability whats occured. ive spoke to trading standards who have informed me that if the materials combined with the weather are the cause then fact that ive only supplied the labour and installed the drive with due care in proper fashion etc. should keep me from blame! tell that to the customer!!

[Hux]

My sympathies to Topgrafter2007. Been searching tinternet for answers to same problem. Have relaid a mixture of Raj Green paving and coping on a landscape project 3 times and each time the majority of it has lifted. The paving first went down October-November '08. First time we laid it we used (as always) building sand and cement at 6:1. The second time we added a plastercising agent and richened mix to 5:1. On the last attempt we added frostproofer, made sure the temperature was well above +4c, one enthusiatistic employee even scored the back of the slabs with a cutter to increase adhesion. Each time we laid the paving we covered to protect from frost for at least a week. Now we have had some seriously cold weather(-6s and -7s) here in the midlands, but we took all the right precautions and tried to avoid the worst of the weather when actually laying the slabs. I've done similar jobs during cold spells and never had this problem. Each time the slabs have simply lifted off of the mortar, the mortar itself has been strong and sound. I just can't work it out and it's losing me a shed load of money as the job is being done to an agreed price. As the mortar bed is is ok I'm going to try and resin bond the slabs back on. But due to the cost of the epoxy product I'm using I'll probably find it cheaper to chip out all the mortar and relay again with SBR in a stronger mix-or nail the damn things down! Anybody got any other solutions? Anyone had success glueing slabs? p.s. The paving is on footpaths, not drives, on 100mm+ base and the only traffic it has recieved is from very nervous tiptoeing landscapers.

[worldofpaving]

Just read this and wondering how you got on with it TG?

Consider that normal concrete sand will bulk by 5% when in contact with water and that water expands by 8% when frozen then you start to see the potential for expansive problems.

The real mystery is why just with the Indian? As Tony says, expansion is possible but would cause cracking and/ or delamination at the very least so my guess is that it must be due to the porosity of this stone because I'm sure water is at the heart of your problem.

Recycling is a wonderful thing but does create the potential for problems as the precise composition of material supplied is often unknown.

WOP

[topgrafter2007]

it would seem many people are having similar issues in my area and others HUX chin up mate most landscapers use recycled sands round here, doing our bit? yeah but main reasons cost! but we havent had weather like recently and if we hadnt then im sure the issue wouldnt have risen its ugly head. someone else suggested the indian stones a poor insulator as opposed to precast products?? transfering the freezing temps to bedding layer then that sets the reaction with recycled sand. hence why it seems to affect indian over other products. im starting to avoid the indian paved jobs now. not ideal in this time but i need to have confidence in my work! ive hit brickwall with my customer as it was labour only and he instructed us to use the recycled sand coz it was 3 times cheaper. now he reckons im to blame! staying clear of recycled sand too, but problem with that is being small buisness yuo cant compete when others are still using the cheaper sands

[worldofpaving]

Is the indian ligher than per sqm than the other paving?

On the face of it natural stone should be denser and thus a better insulator than pre-cast if all else is equal (thickness, etc).

Have you asked the recycled sand supplier for some technical information about the product supplied to you?

I see no reason why you should simply have to take this on the chin and as HUX is suffering as well is clearly symptomatic of a wider issue so perhaps we should combine resources here on the forum and see what we can come up with?

[topgrafter2007]

i see what you mean about density but some indian seem so diff in weight from one to another even in same batch. joys of natural products? and that film you get on the back of them dosent help. we brush it of if we can. as for the recycled sand its just wagon loads of allsorts, brick, concrete, gravels etc. fed into crusher and out pops ??? theres no standards as to what you get and its up to you what you do with it. the people were we got it from arnt bothered as they dont av to gaurantee it for any specific uses...

[worldofpaving]

Because I come from a tech background but have also done installing my thoughts always turn to looking at material specs but clearly this is not going to help us here!

The one thing pre-cast would be is consistent in size weight and thickness and real sand would also be consistent in makeup and thus performance - it doesn't help one iota on the current project of course but we seem to have flushed out the cause of the problem and the only consolation may be that it should help in the future.

Proving it to the satisfaction of a court would, of course, cost money and time both of which are usually not in plentiful supply and event that assumes that there is that much money in the job which on labour only there probably isn't.

I think that this is not the last of the problems that we will see as a result of going green - more and more concrete is being batched using aggregate that has been recycled from truck washouts - yup, it's collected and loaded onto a wagon at the ready mix plant, taken away, washed and graded and delivered back to the same yard for reuse - transport by donkeys? No, the good old diesel engine is right in there............

[topgrafter2007]

i think recycled products will and should be governed more tightly and im sure that day will come. not soon enough for some of us though!! if the goverment want us to use them and im behind it 1000% they should get more involved. but i guess that means the inevitable stealth taxes will be applied??

[Tony McC]

Most Indian sandstone is slightly less dense (lighter per cubic metre) than yorkstone or pennant stone, but there's not enough in it to make a real difference and as for the 'thermal insulation' theory....bollocks!

[msh paving]

Just to add my theory,

when i lay slabs i use a 5-1 mix sharp sand,never soft sand little feb, mixed almost as wet as brikkies muck,lay them on a full bed and tap down to line and level so they stick to the muck,maybe your mix is to dry so there is not enough stick and moisture is getting under slabs and frost lifting them,

i have never used recycled sand no one in this area produces it as we have lots off sand pits,

just my ideas MSH

[topgrafter2007]

lay my jobs just same as you MSH cept only difference is we used recycled sand. not again tho! always laid on wetmix like you too. as for insulation/thermal idea who knows i aint a geologist so couldnt say either way :;):