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W/C should be neither too low nor too high (low W/C resulted in false setting
easily, while high W/C resulted in breeding);
③
small de
ciency like sand hole
④
emerged on concrete slab, and it was dif
higher cost (concrete
cost would be increased by nearly 10 %). However, these demerits could be
overcome by taking construction measures.
All in all, through the experiment, we believed that adding polyester
cult to repair; and
⑤
ber to
Turpan Airport concrete was very necessary for preventing generation of dehy-
dration crack. The effect was quite prominent, especially during the construction
period of daybreak in morning.
Some said, now that experimental result indicated that
fiber was effective during
the construction of daybreak, why not only employ
fiber in this period? We studied
and believed that cement hydration speed would also be accelerated by factors of
sudden strong wind and high-temperature sand and stone due to sunshine in day-
time, etc. during other periods of concrete construction, when
ber was needed to
eliminate generation of dehydration crack. Therefore, it was suggested by experi-
mental group that
fiber be employed in the whole airport concrete construction to
prevent generation of dehydration crack.
16.4.6 Summary on Map Crack
Key point of the experiment was not research and summary on map crack. How-
ever, in research process of dehydration crack, some observation and researches
were carried out on generation of map crack bi the way. Right now, some summary
would be conducted on several phenomenon emerged in experiment (no conclusion
was drawn because relevant comparative experiments had not been conducted),
mainly aiming at supplying some reference to special researcher in the future.
Map crack which emerged after galling (adding admixture)
is shown in
Fig.
16.24
.
Fig. 16.24 Map crack
emerged after galling (adding
admixture)
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