Civil Engineering Reference
In-Depth Information
ought to be less than 90 s, and working voltage was ought to be less than 350 V
and no more than 420 V.
9. When loading raw material, it should be particularly noticed that soil was
forbidden to be involved in case of decreasing concrete quality.
10. Concrete mixture carrier vehicle should be kept clean. No sundries and left
mixture were forbidden to exist in carriage, and no hydrops left by washing
vehicle were allowed.
11. Maximum time of concrete mixture transported from mixing batch to con-
struction
field should be no more than 30 min. The transportation road should
flat and conserved termly in case of concrete breeding or involving of
sundries caused by transportation reason.
12. Mixed concrete mixture should be transported to
be
field as soon as possible for
paving, and staying for a while should be forbidden. Concrete mixture should
be forbidden transporting to
field if concrete mixture exceeded initial setting
time.
13. Transportation vehicles should enter paving
field at low speed, and there
needed specially assigned person for commanding in case of vehicle wheels
impacting mold. If such situation happened, calibration should be conducted
instantly.
14. Mixture paving should be conducted according to construction technical
requirement. Mixture transported to field should be paved instantly and evenly.
If paste leakage or displacement of mold happened, measures should be taken
immediately to calibrate mold.
15. Vibration should be carried out as soon as concrete mixture was paved.
Vibrating spear should be inserted into place which was near to mold, and
operation of vibrating spear should follow instruction of quick enter and slow
out to avoid uneven vibration. Advisable vibrating time should be determined
by the time when surface paste was
flat and no bubble was emitted, or
ne
ed and coarse aggregate was resonated. After that, a panel
pulling vibrator was required to facilitate leveling. Manual leveling should be
supplemented in vibration, and no unevenness was allowed on mixture surface
after vibration.
16. After vibration of untied vibrator, panel vibrator was pulled for smoothing and
it should be vibrated by wooden moving rammer by less than two times.
Purpose of the
aggregate was lique
first wooden moving rammer was as follows:
making mixture
①
surface compacted;
making
concrete surface reach preliminarily smooth. Thus, manual leveling should be
supplemented in vibration, so as to shovel out mixture from high place and
pressing coarse aggregate downward; and
②
③
filled it into chuckhole area. It was the most suitable that mixture which was in
front of wooden moving rammer was 3 cm higher than wooden moving ram-
mer. Wooden moving rammer generally needed to work back and forth for two
times to reach construction requirement. The quality requirement was that steel
nail on the bottom of wooden moving rammer formed a moderate trace on
concrete surface (no trace indicated that concrete plane was too low and more
mixture was needed repair, trace was too high indicated that concrete plane was
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