Code:
<input id="pC" name="pC" type="text" STYLE="background-color: #A9A9A93" placeholder="Blah" class="form-control valid" maxlength="10" value="" disabled="disabled">
That should just grey it out - I didn't test it, but I think that will work...
That would be the standard way of indicating a text field is not editable - You can see 'blablah'.....
https://jsfiddle.net/bwh0cnme/
I always forget about jsfiddle...