Fatal Factor for Durability: Drying Shrinkage - The Issues and Discussion of Modern Concrete Science - page 143

Fig. 11.13 Old parking apron of Urumchi Airport in Xinjiang

extremely high alkali content in water reducer, increasing concrete shrinkage as
well as drying shrinkage [ 2 ].
It is stated by somebody in academia that excessive drying shrinkage crack
caused by adding water reducer can be regarded as alkali-aggregate reaction.
This is also a very severe technical misunderstanding.
6. Effect of cement
After entering twenty- rst century, drying shrinkage crack become more sig-

c surface area of cement,
grinding aid, utilization of high effective separator, extremely high amounts of
aluminates, over dosage of mineral admixture [ 3 ].
7. Effect of

ni cant and serious, this may due to large speci

y ash content
The more the fly ash admixed into concrete is, the more severe the drops of

surface tensile ability and shrinkage cracks in concrete will be [ 4 ].
8. Effect of cement paste thickness on concrete surface
Mortar is place where cement paste are relatively more concentrated. Therefore,
shrinkage stress is stronger when mortar is thicker, so drying shrinkage crack
problem will be more serious. A parking apron of Urumchi Airport in Xinjiang
is a typical example, as shown in Fig. 11.13 .

Parking apron of Urumchi Airport was accomplished in 2001 and the author had
participated in the project. Zebra stripes were generated on its surface since 2003,
and the reason had not been found yet. We did not

find it caused by construction
technology until 2007. It was different thicknesses of mortar on concrete surface
that result in it during constructing. As thinner parts were more easily to be abraded,