As the cost of structures increases so does the need to keep these structures in service for as long as possible. This effectively reduces the life-cycle costs and aids in the investment decision from a time-value of money perspective. Limiting and preventing cracks protects the high alkaline environment that the concrete inherently creates. This, in turn, protects the reinforcement from corrosion. This is one of the most important attributes of concrete durability and one of the hardest to achieve consistently, but that is all about to change.
A new shrinkage reducing/compensating admixture like Sika®Control SRA has the potential to generate a shrinkage neutral concrete, in other words, non-shrink concrete.
High-performance concrete thus is not a single type of concrete, but rather, any number of concrete engineered to possess certain properties suitable for a particular construction application.
Life Cycle Assessment (LCA) is a standardised method to assess and compare the inputs, outputs and potential environmental impacts of products and services over their life cycle. LCA's are increasingly recognised as the best way to evaluate the sustainability of products and systems.
Sika carries out LCA’s according to the ISO 14040 series and the Standard EN 15804. The impact assessment methodology used is CML 2001.
As a standard approach, Sika evaluates all impact categories and resource indicators deemed as important according to the relevant standards. For concrete, categories considered to be most relevant include:
Cumulative Energy Demand (CED)
Cumulative Energy Demand (CED) accounts for the consumption of energy resources, namely the total amount of primary energy from renewable and non-renewable resources.
Global Warming Potential (GWP)
Global Warming Potential (GWP) measures the potential contribution to climate change, focusing on emissions of greenhouse gases, such as carbon dioxide (CO²), which enhance the heat radiation absorption of the atmosphere, causing the temperature at the earth’s surface to rise.
Use of Net Fresh Water
The use of net fresh water accounts for the consumption of fresh water (e.g., feed water, ground water, lake water, river water, surface water, water with river silt).
Concrete admixtures can improve the sustainability of concrete in many dierent ways. Firstly, admixtures can improve the quality and performance of concrete significantly, which in return extends its service life. In addition, thanks to the use of admixtures the application of concrete instead of other building materials can improve the life cycle of infrastructures, i.e. concrete roads greatly improve the quality and durability of highways for main trac arteries compared with conventional road surfacing.
Further, the addition of special admixtures, such as stabilizing or water reducing admixtures also enables the use of alternative and recycled materials, such as recycled aggregates, for the production of good quality concrete. Finally, in many cases the energy required to produce certain cement or concrete mixes will be positively impacted with the use of admixtures. One example is the addition of water reducing and accelerating admixtures to obtain high early strengths in precast concrete to greatly reduced or even completely replaced external heating of elements.