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cement

A cement is a binder, a substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel (aggregate) together. Cement mixed with fine aggregate produces mortar for masonry, or with sand and gravel, produces concrete. Concrete is the most widely used material in existence and is behind only water as the planet's most-consumed resource.Cements used in construction are usually inorganic, often lime or calcium silicate based, which can be characterized as non-hydraulic or hydraulic respectively, depending on the ability of the cement to set in the presence of water (see hydraulic and non-hydraulic lime plaster).
Non-hydraulic cement does not set in wet conditions or under water. Rather, it sets as it dries and reacts with carbon dioxide in the air. It is resistant to attack by chemicals after setting.
Hydraulic cements (e.g., Portland cement) set and become adhesive due to a chemical reaction between the dry ingredients and water. The chemical reaction results in mineral hydrates that are not very water-soluble and so are quite durable in water and safe from chemical attack. This allows setting in wet conditions or under water and further protects the hardened material from chemical attack. The chemical process for hydraulic cement was found by ancient Romans who used volcanic ash (pozzolana) with added lime (calcium oxide).
The word "cement" can be traced back to the Ancient Roman term opus caementicium, used to describe masonry resembling modern concrete that was made from crushed rock with burnt lime as binder. The volcanic ash and pulverized brick supplements that were added to the burnt lime, to obtain a hydraulic binder, were later referred to as cementum, cimentum, cäment, and cement. In modern times, organic polymers are sometimes used as cements in concrete.
World production is about four billion tonnes per year, of which about half is made in China. If the cement industry were a country, it would be the third largest carbon dioxide emitter in the world with up to 2.8 billion tonnes, surpassed only by China and the United States. The initial calcination reaction in the production of cement is responsible for about 4% of global CO2 emissions. The overall process is responsible for about 8% of global CO2 emissions, as the cement kiln in which the reaction occurs is typically fired by coal or petroleum coke due to the luminous flame required to heat the kiln by radiant heat transfer. As a result, the production of cement is a major contributor to climate change.

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  1. S

    Backer / Cement board for low level UFH

    Hi. We have recently bought the ground floor of a Victorian house, about 100 m2. The floors are all laid to very solid floor boards and the ceilings are 3m high. I've had some quotes from a couple of UFH firms, one says they'll lay their product directly onto the exisiting floor boards and the...
  2. gmartine

    18mm cement board for bathroom flooring?

    Third time I'll be doing this floor...first time was weatherproof TnG, 2nd was marine ply both of which were varnished and blew up because of a combination of flooding and careless use. Hardibacker is easy to get from sheds but only in 12 & 6mm which I could overlay. Any other recommendations?
  3. S

    PEX pipe conduit for cement

    I have about 6 metres of 22mm PEX to run through concrete and understand I need to have it in flexible conduit to offer a bit of protection and allow the pipe to expand. Is this the stuff you guys would use or are there other alternative products...
  4. D

    Slow dry solvent cement for ABS

    Hi, does anyone know of a slow dry/cure solvent cement for ABS waste pipes please? Got some 50mm floplast ABS waste pipes in a tricky ceiling that will be a pain to get the cement on, line up and push together before the normal solvent cement goes off - in the 15 seconds you get to fit them...
  5. P

    Is this product suitable as a solvent cement for abs pipes?

    I have this at home: Glue and I need to solvent-weld these abs drain piping: pipe and elbow Can I avoid purchasing solvent cement? Or would that present some problem? Thanks.
  6. W

    Bedding a WC pan down in cement

    I know this works - best used as a last resort - but not sure why.. I was thinking it might be less to do with adhesive properties as it is to do with creating a solid lump inside stopping the pan moving left/right/forward/back. Is that right? Because often when you come to remove a pan that...
  7. Gazzt

    Flue cement keeps cracking

    Has anyone got any advice on how to stop flue cement cracking. I used regin 1200 degrees cement but cracked.
  8. T

    How do I seal a hole in plastic?

    I have a plastic (possibly PVC) pipe I can't replace that has a pinky-sized hole drilled into it. Is there any way I can just seal it up? I've tried using silicone but it just sort of peeled off. Appreciate the help!
  9. H

    Copper pipes and cement mixes

    I know that wet cement/concrete can have a reaction with copper and begin to attack it, so we sleeve it, but can dried set concrete still have any affect on copper pipes installed later on?
  10. H

    Protecting pipes chased into block walls

    Hello forum. First time user here (and now registered)! Can someone please advise the best/recommended method to protect 15mm copper pipes that I will be setting back into a wall to feed radiators in my house. I've already chased the walls, which are standard concrete blocks, but I'm aware of...
  11. A

    Fire cement recommendations

    I've tried most, is there anything out there that's just a little more elastic and can handle thermal expansion.
  12. M

    Cement on copper pipe

    Long story short - having a massive refurb - all copper pipes newly installed I went to a lot of trouble of sinking some copper pipes for radiators in the floor by buying plastic ducting. I am aware that contact with cement may cause degredation of copper pipes in the long term - although...
  13. A

    Worcester Flue protection through wall with lime render

    Hi all, I will be fitting a new flue to a Worcester boiler as the cement has munched through the old flue in a couple of places. My question is there anything that I can wrap the flue with as it passes through the wall to act as a sacrificial protector for the new flue. I have thought about...
  14. M

    White/ very light coloured cement.

    It's been years since I have had to make some and I always use ready mix from the merchants. How do I do it again? Is it white sand and cement?
  15. N

    Strap on boss soil pipe

    Hi all, 1st post!! Have recently noticed the strap on boss on external pipe as a small leak from the underside of where the boss touches the soil pipe, what's the best way to go about fixing this? It holds the connection to bath waste pipe and the leak isn't anything major but have noticed...
  16. T

    Problem with shower tray rocking

    Hi Just need some advice for the corner shower tray that is installed in our bathroom. Noticed that there was a water mark on kitchen ceiling directly below where the shower is installed, so changed the seal around the base, but have also noticed that when stepping in and out the shower it...
  17. M

    How's this for a toilet.....

  18. S

    Plumber has Covered Copper & Steel pipes in Cement, issues later?

    My plumber has covered up some of the hot water pipes running under the floor with cement instead of just fitting the original floorboards back. please see the photo. The original hot water pipes are steel and were unlagged also present are unlagged copper pipes. Should I ask him to dig...
  19. M

    Fitting shower tray on floor boards

    Hey if fitting a shower tray on sand and cement is it ok to fit it straight on to the floor boards? As long as there isn't much movement in the floorboards.
  20. B

    Re Worcestr bosch fitted by non gas safe update after gas safe inspection

    I recently posted re Worcestr bosch fitted by non gas safe The guy from gas safe visited and found the flue was not been sealed to the structure of the building and issued a at risk notice. Gas safe have now told me you will need to employ a Gas Safe registered engineer To fix the...
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