Why did we have the idea of using plastic flakes with concrete ?
Because we need to save the Sand !
To make concrete we need 1/3 cement + 2/3 sand.
Sand and gravel are mined world-wide and account for the largest volume of solid material extracted globally. Formed by erosive processes over thousands of years, they are now being extracted at a rate far greater than their renewal.
Furthermore, the volume being extracted is having a major impact on rivers, deltas and coastal and marine ecosystems, results in loss of land through river or coastal erosion, lowering of the water table and decreases in the amount of sediment supply. Despite the colossal quantities of sand and gravel being used, our increasing dependence on them and the significant impact that their extraction has on the environment, this issue has been mostly ignored by policy makers and remains largely unknown by the general public.
One way to estimate the global use of aggregates indirectly is through the production of cement for concrete (concrete is made with cement, water, sand and gravel). The production of cement is reported by 150 countries and reached 3.7 Billion Tons in 2012. For each Ton of cement, the building industry needs about six to seven times more tons of sand and gravel. Thus, the world’s use of aggregates for concrete can be estimated at 25.9 Billion to 29.6 Billion tons a year for 2012 alone.
Added to this are all the aggregates used in land reclamation, shoreline developments and road embankments (for which the global statistics are unavailable), plus the 180 Million tonnes of sand used in industry.
Taking all these estimates into account, a conservative estimate for the world consumption of aggregates exceeds 40 Billion tonnes a year. This is twice the yearly amount of sediment carried by all of the rivers of the world, making humankind the largest of the planet’s transforming agent with respect to aggregates. This large quantity of material cannot be extracted and used without a significant impact on the environment. Extraction has an impact on biodiversity, water turbidity, water table levels and landscape and on climate through carbon dioxide emissions from transportation. There are also socio-economic, cultural and even political consequences. In some extreme cases, the mining of marine aggregates has changed international boundaries, such as through the disappearance of sand islands in Indonesia (New York Times 2010).
Most sand from deserts cannot be used for concrete and land reclaiming, as the wind erosion process forms round grains that do not bind well.
Impact on marine biodiversity
The mining of marine aggregates is increasing significantly. Although the consequences of substrate mining are hidden, they are tremendous. Marine sand mining has had an impact on seabed flora and fauna. Dredging and extraction of aggregates from the benthic (sea bottom) zone destroys organisms, habitats and ecosystems and deeply affects the composition of biodiversity, usually leading to a net decline in faunal biomass and abundance or a shift in species composition.
Coastal and inland erosion
Erosion occurs largely from direct sand removal from beaches, mostly through illegal sand mining. It can also occur indirectly, as a result of near-shore marine dredging of aggregates, or as a result of sand mining in rivers. Damming and mining have reduced sediment delivery from rivers to many coastal areas, leading to accelerated beach erosion.
By 2100, global average sea level rise is expected to reach 0.26 to 0.55 meters under the best-case scenario (of 70% reduction of greenhouse gas emissions), and nearly one meter under unabated increase in greenhouse gas emissions. This problem is particularly acute for small islands states, where retreat options are limited. In the Maldives, a few of the largest and highest islands, such as the capital city, Male, are being consolidated to ensure they can host the population displaced from low-lying islands. To strengthen the city, a large amount of sand is being imported to Male, to be used in building higher towers and coastal protection. The sand is taken from offshore sand islands. Paradoxically, the sands extracted for the protection measures in Male are leading to the lowering of some islands, increasing the need to relocate their populations.
Completed in 1990 at a cost of US$ 70 million, a tetrapod wall was constructed to prevent coastal erosion along the edges of the Male in the Maldives.
In Morocco, half of the sand – 10 million cubic meters a year comes from illegal coastal sand mining. Sand smugglers have transformed a large beach into a rocky landscape between Safi and Essouira. In some locations, continued construction is likely to lead to an unsustainable situation and destruction of the main natural attraction for visitors — beaches themselves. Read more about the “Sand War”
Department of Civil Engineering, Rajamangala University of Technology, Thailand said:“Training of architects and engineers, new laws and regulations, and positive incentives are needed to initiate a shift for lowering our dependency on sand. Renewable and recycled materials need to be targeted for building houses and roads.”
We must reduce the consumption of Sand !
That’s why we propose to mix plastic flakes in concrete to save the sand !