1. it is cheep as compared to synthetic chemicals like resins,epoxy etc.
2. It provide compressive strength with aggregate & durability in concrete structures similar to the other building materials used in construction of buildings.Thus whole building component complete its life almost simultaneously.
3. More technically the binding material ( cement) also act as filler in voids of sand in concrete making concrete impervious.
4. As compared to synthetic organic substitutes of cement,cement is inorganic like aggregate & thus bond of aggregate & cement is stronger.
5. All constituent of concrete including cement has slimier thermal coefficients thus formation of crack due to elongation of individual materials of concrete under heat of sun is negligible & same is true in cold weather.
6. Cement is prepared to suit building construction like its intial setting time,final setting time,resistance to acid thus behavior of cement can be controlled or modified unlike lime or mud (soil) or stone dust.
Lime or gypsum can replace cement but cement has better quality w.r.t. crack, less reaction with carbon dioxide of atmosphere,early gain in strength,higher pot life than lime,Mud can also replace cement in temporary single story structures of earth quack free,flood free location.
Two other materials comprise concrete: Aggregate and water. Insofar as other cementitious materials, fly ash and silica fume may substitute for a portion of the cement in concrete mixtures for properties such reduced alkali-silica reactivity between cement and aggregate (fly ash) and increased compressive strength (silica fume).
Cement only cheaper than other material comparatively with strength other than any Synthetic material. easy to use not much toxicity when using time & very safe to handle. Cold curing with water is enough , no more special heat treatment required.
Bcoz it acts as a binder and it also gets hard on drying.
