GGBS

[acresswell]

Anyone got any experience of specifying a high-level of GGBS ( Ground, Granulated Blast-furnace slag) in ready-mix concrete?

My brother-in-law sells cement products in bulk to ready-mix suppliers, and is definitely a "fan" of GGBS... He's convinced me of its green benefits, and I've found various websites suggesting that you can replace up to 70% of the cement with GGBS but the examples seem to mostly be for big building projects like tunnels and bridges.  I'm a bit unsure of how the ready-mix companies will respond if I ask them for it for a smaller project...   we've got to put up a retaining wall as well as deep foundations, so anything I can do to lower the carbon cost of the concrete has got be a good thing!

Thanks in advance

[eabadger]

is it that dark grey / black stuff, they used to make blocks from? power station cinders
if so i had a job in the early 80's which was drilling lots of holes in this stuff for weeks on end, had breathing problems ever since.
maybe different stuff, but we all had issues after working with these 70's/80's cinder blocks.

steve

[acresswell]

If it came from a power station, then I suspect it was PFA (Pulverised Fuel Ash). GGBS is whiter than ordinary cement, according to www.ukcsma.co.uk/ggbs_concrete.html (so if it was dark grey then it's unlikely that it was GGBS)

I'm quite sure that from a technical point of view that GGBS will do what I need it to do.  I know it ends up just as strong as ordinary cement, but takes longer to harden (not a problem for the foundations, and for the retaining wall we'll just leave the formwork up a bit longer). My brother-in-law reckons that GGBS is actually cheaper than cement, so it could even get me a cost-saving... but there's no point specifying it on the schedule if it's likely that noone will want to supply it... so I'm interested in knowing anyone else's experience of telling a ready-mix company what you wanted in your concrete...did they just tell you to "XXXX off", or welcome you with open arms? I'm obviously going to ring up a few local companies before committing to anything, but I want to be prepared for their likely response.  Is there anything else I should ask them / they'll need to know?

And also... anyone got experience of using GGBS with a concrete pump?  It'd sensible to use a concrete pump for the last 30 metres (steep hill so barrowing would truly be a last resort, very narrow driveway so mixer truck is unlikely to get close enough without falling "off the edge").  I assume that when they're building big bridges, etc with GGBS they use huge concrete pumps, but do the smaller pumps still work OK with it?

Thanks,

Adrian

[eabadger]

make sense about the ash, because we all after this job became allergic to coal, being near a coal fire triggers an attack.
i was told then the cost savings were emmence, but i assume due to adverse health issues they have now stopped.
like lots of things including asbestos it is stable until broken or turned to dust.
i am trying to go 0 bad products from now on, probably due to the problems new items had on my and my fellow engineers health.

can your bil not advise you about this if he sells it?

steve

[acresswell]

Yes, had lots of "input" from brother-in-law on the technical side...   but he doesn't have first-hand experience of use of GGBS on a small scale, and especially not of procuring it on a small scale from the ready-mix companies.

[tz0c0s]

The construction industry is on its knees, you may find a better reception awaits than you expect. Go for it.

Regards Andy