Re: [papercreters] Re: Borax

Some of the calcium changes into lime when reacting with the water. Here
OPC does not contain lime, it changes into lime in the chemical
reaction. Even your EU standards don't include lime except possibly in
the unspecified "other compounds" which are a small part at best. What
you posted does not say lime is part of those compounds.

If it makes you happy, sure I use lime in my pc, even though none of the
ingredients I put in the mix contain lime. I give up. You win.

Since the cement reacts and becomes partially lime, and lime absorbs CO2
to eventually become limestone, I mix my pc with limestone.

This whole discussion has been a waste of time and contributed nothing.
I apologize to the group for being drawn into it. It won't happen again.

On 5/27/2013 4:34 PM, prrr.t21@btinternet.com wrote:
> The point is that opc does contain some Calcium hydroxide, aka lime.
>
>
> --- In papercreters@yahoogroups.com, spaceman <Spaceman@...> wrote:
>> I'm not sure what your point is. While portland cement MAY contain other
>> compounds, those compounds generally are not lime. The portland cement I
>> buy complies with the standard I posted yesterday and has no lime. Are
>> you still trying to insist that I use lime in my papercrete? I do not.
>>
>>
>> On 5/27/2013 4:14 AM, prrr.t21@... wrote:
>>> Wikipedia:
>>>
>>> When traditional Portland cement is mixed with water the dissolution of calcium, sodium and potassium hydroxides produces a highly alkaline solution (pH ~13):
>>>
>>> Calcium hydroxide is building lime.
>>>
>>>
>>> European Standard EN197-1:
>>>
>>> Portland cement clinker is a hydraulic material which shall consist of at least two-thirds by mass of calcium silicates (3 CaO·SiO2 and 2 CaO·SiO2), the remainder consisting of aluminium- and iron-containing clinker phases and other compounds. The ratio of CaO to SiO2 shall not be less than 2.0. The magnesium oxide content (MgO) shall not exceed 5.0% by mass.
>>> So upto a third by weight of cement is other things than calcium silicates.
>>>
>>>
>>> (For some reason its not quoting your post.)
>>>
>>>
>>>
>



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