Summary Report of Experimental Study on Dehydration Crack Appearing in the Construction of Turpan Civil Airport Cement Concrete Pavement - The Issues and Discussion of Modern Concrete Science - page 226

At 23:08, rotary drum started working and paste thickness was proper.
At 23:17, wooden trowel started working for the first time and consistency of

paste was found to be proper.
At 23:27, wooden trowel started working for the second time.
At 23:41, wooden trowel started working for the third time.
At 0:00, there was 3-grade breeze which was stronger than the breeze past two
days. Working of iron trowel accelerated, and troweling machine was temporarily
decided to be used for troweling at rst.

At 0:06 0:37, troweling machine was not stop working until all work in this

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section was finished and then transferred to napped experimental section; covering

cloth was started at 3:01 in this section.
At 0:35, field wind force decreased to 1 2-grade, and construction transferred to

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normal state.
At 0:31, concrete of experimental section which employed Tianshan cement and
admixture started pouring. Experimental crews examined air content and temper-
ature at the same time.
At 0:40, rotary drum started working.
At 0:43, wooden trowel started working.
At 1:00, C.

At 1:11, experimental section which employed Tianshan cement and admixture
started napping.
At 2:45, experimental section which employed Tianshan cement, admixture, and

field temperature always stayed around 31 °

fiber started pouring concrete.
At 5:00, concrete pouring work finished completely.

At 6:30, covering cloth on the whole field was finished and experiment on that

day stopped for a period.

(b) Observation and summary

At 11:31 (Beijing time) on the forenoon of July 8, all experimental crews had
observed the section constructed on July 7. Firstly, workers uncovered cloth and
then washed the slab by water. Observation was conducted according to casted
sequence the previous day night, and results were as follows.

(i) Tianshan cement section which employed admixture and ber.

There were 3 cracking slabs in Tianshan cement section which employed
admixture and fiber. The total number of cracks was 3, and their overall

length was 16 cm, as shown in Fig. 16.11 .
(ii) Tianshan cement section which employed admixture.

The first slab: One crack. Its length was 7 cm, and its width was nearly 1 mm.

The second slab: Four cracks. Their lengths were 7, 16, 11, and 9 cm,
respectively, and the width was nearly 1 mm.
The third slab: No crack.