7.3.3 The parameters loss rate
From Fig. 18, it can be seen that different experiments might have
different effects on the deterioration to samples. The effect of acid
rain cycle on the parameters loss rate of samples is greater than that
of samples depending on the dry-wet cycle and freeze-thaw cycle, and the
greatest in pH=2.6. The samples are also deteriorated by the dry-wet
cycle and freeze-thaw cycle as well. Among them, the parameters loss
rate of saturated group is higher than that of samples after the dry-wet
cycle, and the lowest in dry group. The parameters loss rate of samples
follows this order:
pH=2.6>pH=4.1>pH=5.6>saturated
group>dry-wet cycle>dry group. This indicates
that the samples are more susceptive to the effects of acid rain cycle.
Furthermore, the drop in parameters of LA samples is larger than that of
LB samples in different experiments, signifying that the sandstone of
bedding development is among the first to be affected by weathering. The
results suggest that the weathering degree of the upper part of Niche of
Sakyamuni Entering Nirvana is more serious than that of the middle part
accompanied by a large amount of granular disintegration.