Sustainability

Why Concrete Can Be Considered Environmentally Unfriendly

There’s no mys­tery as to why con­crete is envi­ron­men­tal­ly unfriend­ly. In fact, gain­ing insight into that ques­tion is fair­ly sim­ple. Let’s start the dis­cus­sion on how con­crete is made.

Concrete is "of the earth". We extract the ele­ments that go into mak­ing con­crete out of rock and earth. The next step after col­lect­ing the rock is to grind it into a pow­der. So far, so good. In the most ele­men­tal sense, pow­dered cement is green”. In its pow­dered form, cement is also biodegrad­able. Its envi­ron­men­tal­ly friend­ly ways go down­hill from there.

We make con­crete by mix­ing cement mate­r­i­al with sand or fly ash and grav­el, lime­stone or gran­ite, and enough water to allow the mate­r­i­al to set”, there­by bind­ing it togeth­er. We make cement for that recipe by fus­ing togeth­er lime­stone and clay, sub­ject­ing them to great heat, and then grind­ing the com­bi­na­tion into a pow­der.

Why concrete is not environmentally friendly. In gen­er­al, it is not the ingre­di­ents, so much as the process­es we use to make con­crete that fail the sus­tain­abil­i­ty test.

  • Quar­ry­ing for the sand and oth­er aggre­gate mate­ri­als like lime­stone or gran­ite can destroy and pol­lute the mine area.
  • To make cement takes a lot of ener­gy and water.
  • There’s a lot of waste in the mix­ing process. The con­crete hard­ens quick­ly and if there’s not enough time to lay it down before it hard­ens, builders just throw it away.
  • Con­crete is known for its high car­bon emis­sions into the atmos­phere, which con­tributes to green­house gas­es. This occurs in the process of mak­ing cement when the clay burns at high tem­per­a­tures and the lime­stone burns to cre­ate the high tem­per­a­tures. Big car­bon foot­print here.

But what would we do without concrete? Con­crete is the most com­mon build­ing mate­r­i­al in the world. We use it for our build­ing foot­ers and our base­ment walls and floors. We build our homes on slabs made of con­crete. We use con­crete to fin­ish our dri­ve­ways. We cre­ate side­walks and stairs and porch­es around our home from con­crete. We would­n’t have our built-in pools with­out this ver­sa­tile build­ing mate­r­i­al. We use con­crete for the mor­tar that holds our brick fire­places and brick walls togeth­er, and for our patios and even bench­es to sit on. Is there any­thing to replace con­crete in a sus­tain­able way? The answer is yes.

Three Advances in Concrete

Pervious Concrete. One envi­ron­men­tal­ly friend­ly prod­uct that replaces tra­di­tion­al con­crete as a paving sub­stance is per­vi­ous con­crete.

Tra­di­tion­al con­crete is envi­ron­men­tal­ly unfriend­ly with respect to the health of our water sup­ply. As con­crete cov­ers more of our ground, less rain­wa­ter soaks into the soil. Tra­di­tion­al con­crete is imper­vi­ous to water and so the water just runs off the paved sur­faces. This cre­ates lots of prob­lems, the most notable soil ero­sion, flash flood­ing, deplet­ed water table resources, and pol­lu­tion from our oil-soaked and deic­ing-chem­i­cal-filled road­ways.

More and more busi­ness­es and local­i­ties have switched to per­vi­ous con­crete. Per­vi­ous con­crete is a porous mate­r­i­al that helps hold stormwa­ter runoff so that it per­co­lates into the ground and refills the water table. So instead of gush­ing down your dri­ve­way to the street gut­ters and sew­ers, your porous dri­ve­way, side­walks, patio and pool areas snag the rain­wa­ter and hold it in tiny voids until it slow­ly seeps into the ground like nature intend­ed.

CO2 Absorbing Concrete. A British man­u­fac­tur­er called Novacem claims that it has devel­oped a new kind of con­crete that absorbs large amounts of car­bon diox­ide dur­ing the hard­en­ing process instead of emit­ting car­bon gas­es. Novacem claims its prod­uct can absorb .6 tonnes of CO2 com­pared to tra­di­tion­al con­crete which emits .4 tonnes of CO2.

The prod­uct is still in tri­al stages but would sig­nif­i­cant­ly impact the build­ing mar­ket if it were avail­able for builders to use and design­ers to require.

Composite Cement. The Bau­tex wall sys­tem is based on a com­pos­ite mate­r­i­al that com­bines EPS foam beads with cement to pro­vide an improved method of con­struct­ing walls. The Bau­tex wall sys­tem pro­vides the storm resis­tant strength, fire­proof prop­er­ties and ease of con­struc­tion of tra­di­tion­al con­crete walls. It also pro­vides insu­lalt­ing, sound absorb­ing, weight sav­ing, mois­ture resis­tance of foam.

The use of foam in the com­pos­ite also reduces the amount of cement required to pro­vide a more envi­ron­men­tal­ly friend­ly solu­tion. The result is a high per­for­mance wall sys­tem that saves ener­gy, is faster to install, has less chance of instal­la­tion errors and is more envi­ron­men­tal­ly friend­ly.

To talk more about this, or any­thing else, please con­tact us. We look for­ward to shar­ing our ideas with you.