Dear reader conservation of energy and material is common feature that are considered very frequently in application and development of different technology.
We know concrete constructed of fine aggregate, coarse aggregate, binding materials (most commonly cement) and some admixtures or additives in the presence of water.
In case of fine aggregate artificial sand and crushed glass particles are using to conserve natural sand. The coarse aggregates are also replaced by some extent or fully by glass particles, industrial by-products and recycled products.
Aggregate from crushed concrete is included in ASTM and ACI code providing some provisions. The replacement of aggregate by glass, by-products or crushed concrete always associated with some unexpected reactions while hydration which are mitigated by necessary modification by adding flyash, ASR controlling admixtures and pozzolanic modification of aggregate (say fineness).
The most costly element of concrete is cement which is also partially replaced by different pozzolanic materials and industrial by-product (say BFS). So we have some idea about conservation of concrete materials. We can conserve materials also by providing longer service life of concrete structure, which is achieved by durability considerations; thus furnishes an ecological step.
Now concrete is using in many challenging environment having industrial exposure, hostile marine environment and as container of corrosive chemicals or pressurized gas vessels. Concrete pipes are using in many purposes of industrial and municipal activity. This exposure extremity also forced designer to be conscious about durability.