The 1st pictorial diagram illustrates the phases and equipment used in the 
cement
-making process and 2nd pictorial diagram shows how it is Use synonyms
then
 used for Linking Words
production
 Correct article usage
the production
concrete
 for building purposes.  
Change preposition
of concrete
Overall
, limestone and clay pass through four stages before being bagged Linking Words
ready
 for use as Correct word choice
and ready
cement
 which Use synonyms
then
 accounts for 15% of Linking Words
four
 materials used to produce concrete. Correct article usage
the four
While
 the process of making Linking Words
cement
 uses a number of tools, the production of concrete requires only a concrete mixer. 
In the first stage of making Use synonyms
cement
, limestone and clay are crushed together to form a powder. Use synonyms
This
 powder is Linking Words
then
 combined in a mixer before passing into a rotating heater which has constant heat applied at one end of the tube. The resulting mixture is ground in order to produce Linking Words
cement
. The final product is afterwards put into bags ready to be used.
Regarding the Use synonyms
second
 diagram, concrete consists of mainly gravel, which is small stones, and Linking Words
this
 makes up 50 Linking Words
percent
 of the ingredients. The other materials used are sand (25%), Change the spelling
per cent
cement
(15%) and water(10%). These are all poured into a concrete mixer which continually rotates to combine the materials and ultimately produces concrete.Use synonyms