Monday, November 16, 2009

[papercreters] Re: ASTM Type Standards for PC

Ashok,

This has been discussed extensively on the list and in sub groups created to attempt ASTM certification. Papercrete is better thought of as a wood product than a cementitious one. It reacts to moisture, pressure, cutting apparatus and fasteners much more like wood than cement. It has higher insulative values, is more susceptible to destruction by flame but less susceptible to catastrophic compressive failure.

All that said, currently the only (non-experimnetal) code that I know of that covers it is the NM Adobe standards mentioned in earlier posts. The testing and certifications are expensive and there is not much value for companies since they cannot patent the PC itself. And since there is no "standard" that can be checked against, inspectors are likely to be wary of PC used in any structural fashion. I personally see PC's best hope as an insulative infill for post and beam construction, not because I think PC will fail structurally but because I see no one with a large enough economic incentive to prove that it will not.

- Ernie

--- In papercreters@yahoogroups.com, Ashok Mathur <ashokchand2000@...> wrote:
>
> It appears to me that the characteristics of a PC block are substantially different from those of a conventional brick or that of a conventional cement block.
>
> For instance, a conventional cement block or a conventional brick cracks apart when subjected to excessive compressive load. In contrast, a PC block does not crack apart, it rather loses its depth ie, it compresses in size and can regain the compression substantially when the compressive forces are removed.
>
> A Conventional brick or cement block has very little insulation properties.A PO block can have significant insulation properties.
>
> To me it appears that the ASTM tests for bricks and cement blocks are not fully relavent to PC blocks.
> In the building code we should ensure that standards that are laid down for PC blocks reflect their unique properties also in addition to what conventional builders look for.
>
> Regards
> Ashok
>


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