Important Raw Material—Coarse Aggregate - The Issues and Discussion of Modern Concrete Science - page 26

Fig. 2.2 Sandstone ( left ) and limestone ( right )

Fig. 2.3 Sandstone in
Shaoguan, Guangdong
Province

Granite is the most common igneous rock. It is also acid rock but not extrusive
rock. Granite is generated by long time cooling of magma from volcano bottom to
crater during the process of volcanic eruption. According to the length of cooling
time, different sized and most macroscopic crystalline particles sequentially formed
from volcano bottom to crater are called fine, medium, coarse-grained granite,

respectively, on the project.
The appearance of basalt is dark gray. Although it is also igneous rock and
extrusive rock, it is formed by rapid cooling of magma ejected to ground during the
process of volcanic eruption. Andesite and rhyolite are formed simultaneously for
containing different amount of other minerals. They are collectively referred to as
extrusive rock. These rocks are ejected from underground instantly with thousands
of degrees Celsius, and the temperature drops sharply after reached the ground,
making the formed rocks have the characteristics of dense and solid. The most
typical and standard basalt is six prism, such as basalt in Zhangzhou of Fujian
Province and Jining of Inner Monglia, as shown in Fig. 2.5 . Partial parts of basalt in