Re: [papercreters] Re: Borax

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@btinternet.com 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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