Materials Man

Does major industry use QA to hide behind? The cement industry appears to have accomplished this, who in the last 40 years remembers testing cement? we all now receive cement certs as a given, never challenged, well how could you? it’s from a factory like an AUDI car, problem is when we have driven the product we can’t sort out why the brochure product is not as advertised, we consumers of ready mix are the ultimate users, denied as real customers by the suppliers who use the powder, no link to powder maker so door shut. Is cement a hugely variable product, unknown to its true, down the line customers ? It’s base line for compliance is so low and set by themselves that it could vary enormously above it’s minimum.

Think about concrete durability for trunk roads in Scotland, all codes are ignored and the employer ’s requirements specify a minimum requirement of a free W/C ratio of 0.4. Does this not tell you about free w/c ratios in actual production and the trust in the ready mix industry?

I would like to see more cement testing, problem is, it will comply, my concern is how variable is it? Don’t see clients specifying this, it would seem to be the province of a ready mix supplier who buys cement from another company. Probably it is happening, but will we users of ready mix ever find out?

Am I too cynical?

How hard can it be to mix four ingredients to produce a stated outcome? aggregate, cement, water and an admixture (or two) We have probably done three of them around the house with a shovel and a board. I once made a whole patio of slabs with my own formwork with embedded red chips floated into the surface. and the real reason for doing it was to prove a mason wrong, whilst having a pint with him he declared, you will never make them frost resistant! Want a bet, I internally cogitated? I was impressed one of his durability factors was frost attack. Most builders still adhere to washing up liquid being a cure all.

I have to admit to having been responsible for several project based concrete mixing plants both here and in the Middle East, so I can answer my own question. Things can and do go wrong. That is what worries me about European specifications where the supplier is in charge of declaring the quality of his own production. Sure we can do identity testing and it’s frequency can be every load if the client wants. It’s not the same as conducting compliance testing to the same spec as the supplier uses, only collecting and using more data. Yes the suppliers have QA and it is third party accredited, they often own the cement source as well so when and if the cement strengths take a tumble, they as internal customers, should be first to know, Aye right! My best supply of concrete has come from small family concerns supplying to medium sized projects, why is it that supply from the majors is so inconsistent? I have sworn never to work with certain suppliers, but when forced to, say 200 miles away from the “we will never work together again” project, they are brand new! this has happened to me several times, and to others who may comment on this post.

Seems to come down to people, not systems, my pint sharing mason couldn’t make durable concrete, where my red slabs outside my back door testify that I can.