In recent years, chemical reaction bonding has been tried for
the production of building materials. Sodium hydroxide and
orthophosphoric acid were used as chemical binders in this
~nvestigation. These chemical binders are uniformly dispersed
1n earth mud at a concentration level of 1.0 and 2.0 wt% NaOH,
and 0.2, 0.5 and 1.0 wt% H3P04 in presence of 10-12 wt% moisture
in separate batches. The homogeneously mixed mass is compacted
into blocks which are dried at room temperature and
373 K for 1 h and subsequently reaction bonded at 573, 673, 773
and 873 K for 1 h in air. The earth mud building block consisting
of 1% (by weight) NaOH + 0.2% H3P04 and reaction bonded at
673 K for 1 h shows CCS of 8.0 MPa. Hand compacted earth mud
~uilding block consisting of 1% NaOH and 0.5% H3P04 , which is
f1red at 673 K for 1 h in air, shows CCS of 6.0 MPa. The above
mentioned building blocks show good resistance to water swelling
and fluctuations in environmental conditions. |