Conc­re­te is the most wide­ly used buil­ding mate­rial in the world - not least because it can be used for a wide varie­ty of uses and sizes. The popu­lar mate­rial is made of conc­re­te by its low cost, abi­li­ty to withs­tand mois­tu­re, compres­si­ve strength and stiff­ness, and wor­ka­bi­li­ty. In addi­tion, conc­re­te is a fire­proof mate­rial and does not relea­se harm­ful subs­tances. As a fra­me mate­rial, conc­re­te is also sui­table for lar­ge struc­tu­res that are in con­tact with water or soil. Even more often than in buil­ding con­struc­tion, conc­re­te is used in infra­struc­tu­re con­struc­tion such as in the manu­fac­tu­re of tun­nels, brid­ges or pipelines. 

Conc­re­te is made of water, cement and aggre­ga­te, ie comple­te­ly out of natu­ral mate­rials, which at the same time makes it a good but eco­lo­gical­ly unsus­tai­nable pro­duct. The bin­der, cement is main­ly made from limes­to­ne by bur­ning, which con­su­mes a lot of ener­gy and also gene­ra­tes a con­si­de­rable amount of car­bon dioxi­de in the process. Ordi­na­ry drin­king water is sui­table for the pro­duc­tion of conc­re­te, the use of which is alrea­dy proble­ma­tic in itself. Aggre­ga­te is the main mate­rial of conc­re­te and can be crus­hed, natu­ral gra­vel or natu­ral sand. The abo­ve-men­tio­ned mate­rials are avai­lable almost inde­fi­ni­te­ly, but sand, for example, has beco­me the world’s second most sought-after natu­ral resource. In the pro­duc­tion of conc­re­te, the raw mate­rials first have to be procu­red up to the other side of the glo­be, and only then is the finis­hed conc­re­te mass trans­fer­red to the con­struc­tion site. This move­ment natu­ral­ly causes a lot of traf­fic emis­sions that pol­lu­te the environment. 

Howe­ver, from an envi­ron­men­tal point of view, the envi­ron­men­tal impact of conc­re­te as a buil­ding mate­rial should be con­si­de­red throug­hout the life cycle of the buil­ding, focusing on two aspects: 

What is the ener­gy con­sump­tion during the life cycle of the building? 

How have natu­ral resources been used and is the amount of was­te minimized? 

Pic­tu­re: Jose­fii­na / Tri­fa­mi 3D

It is pos­sible to recycle the conc­re­te comple­te­ly. In addi­tion, crus­hed conc­re­te, ie recycled conc­re­te or surplus conc­re­te, can be used as the aggre­ga­te for new conc­re­te. In the past, crus­hed conc­re­te has been used main­ly for the pro­duc­tion of conc­re­te for civil engi­nee­ring, but it is also known to be sui­table for buil­ding con­struc­tion. The long ser­vice life of the conc­re­te buil­ding, good ener­gy eco­no­my and recycla­bi­li­ty of mate­rials, as well as car­bon seque­stra­tion, also com­pen­sa­tes for the emis­sions caused by the con­struc­tion phase. 

At the same time as the pro­duc­tion of vir­gin conc­re­te puts an unrea­so­nable bur­den on the earth, vio­lent natu­ral phe­no­me­na such as earthqua­kes and floods are cons­tant­ly inc­rea­sing and often the only tech­nical­ly sus­tai­nable solu­tion remains conc­re­te con­struc­tion. Conc­re­te is not as bad as its manu­fac­tu­ring process - it is still one of the most impor­tant buil­ding mate­rials with a lot of good pro­per­ties. From a circu­lar eco­no­my pers­pec­ti­ve, the use of recycled pro­ducts in par­ticu­lar plays an impor­tant role in con­struc­tion: they save natu­ral resources, reduce was­te and reduce cli­ma­te emis­sions. At the moment, the most impor­tant thing is to deve­lop the pro­duc­tion of conc­re­te and conc­re­te con­struc­tion in the most sus­tai­nable and eco­lo­gical­ly efficient way possible. 

Read more about this topic: 

Conc­re­te Industry Associa­tion’s web­si­te https://betoni.com 

The­sis: Uti­liza­tion of crus­hed conc­re­te as recycled aggre­ga­te in conc­re­te (Nie­mi­nen, A-M., 2015) http://urn.fi/URN:NBN:fi:aalto-201512165726 

The­sis: Was­te or lost poten­tial ?: reuse of conc­re­te was­te (Aal­to­nen, S., 2019) http://urn.fi/URN:NBN:fi:amk-2019122027737