Our industry is meeting the needs of a changing world. We continue to work to evolve the production and use of cement and concrete in order to make an even greater contribution to sustainable development.
Introduced in Canada in 2011 and referenced in the National Building Code under the name of Portland-limestone cement, the new lower carbon Contempra cement reduces CO2 emissions by 10%, while producing concrete with an equivalent level of strength and durability to concrete produced with regular Portland cement. This is done by intergrinding regular clinker (the main ingredient in cement) with up to 15% limestone, which is 10% more than in regular Portland cement.
Ultra-High performance concrete (UHPC) permits the construction of exceptionally light, strong, durable and long service life structures using less concrete more efficiently. One of the key applications for UHPC is for critical infrastructure, where long service-life in increasingly harsh environments is desired. Due to the material’s superior compressive and flexural properties, the need for passive reinforcing can be eliminated or greatly reduced (depending on the application). It is also highly moldable and replicates form materials with extreme precision, allowing for thin, complex shapes, curvatures and customized texturesnot possible with traditional reinforced concrete. UHPC can bring even higher levels of durability and longevity benefits to buildings and structures and can also be referred to as self healing concrete because of the vast amounts of cement powder in the mix and the very low water/cement ratio that is used. The unhydrated cement powder hydrates when exposed to moisture in a crack.
Photocatalysts keep concrete clean and depollute the air we breathe. When used on or in a concrete structure, photocatalysts decompose organic materials such as dirt, including: biological organisms, mold, bacteria; airborne pollutants, including: volatile organic compounds, and the nitrous oxides [NOx] and sulfuric oxides [SOx] that are significant factors in smog. It is also self cleaning (based on particles of titanium dioxide). Still in the experimental stages in North America, these new cements can reduce urban smog by containing materials that act as a catalyst to bind airborne nitrogen and sulphur oxides into insoluble salts. In Canada, the Ministry of Transportation of Ontario (MTO) is conducting a pilot project with a section of noise barrier on Highway 401, and will compare results against test benchmarks achieved in other countries.
PRECAST CONCRETE PAVEMENTS
Precast concrete pavement is a long service life solution for rapid construction and rehabilitation of existing pavements with short construction windows. Precast panels are fabricated and cured in a controlled environment so on-site curing time is not required. A successful trial of precast concrete pavement to fasttrack repairs on Ontario’s Highway 427, one of the busiest highways in the Greater Toronto Area, led MTO to use the technology for repairs on high volume freeways as a rehabilitation strategy to minimize lane closure duration and traffic delays and reduce work zone hazards.
Pervious concrete pavements and permeable interlocking concrete pavements
A major innovation in the industry is the development of permeable interlocking concrete pavement (PICP) and pervious concrete pavement (PCP), which allows water to pass through the pavement and percolate into the native soil, filtering and decomposing many of the contaminants that would otherwise enter the natural watershed. By collecting and storing stormwater under our parking lots and sidewalks, pervious paving systems reduce the need for retention ponds and provides more usable space on a site. PICP and PCP help reduce and clean storm water runoff, replenish aquifers, protect our streams and lakes, and — in urban environments — help reduce the heat island effect and allows water and oxygen to reach the roots of our trees.