Classifying Concrete Admixtures: Water reducing admixtures and Waterproofing Admixtures
With an increase in the residential building market forecasted for 2014, the demand for concrete across Nigeria is expected to follow suit. Extensive evidence has shown that concrete structures around the world are not meeting their designed service life, due to rapid deterioration – all of which is caused by the transport of fluids and moisture through the concrete. Concrete structures have traditionally had a design life of 50 to 100 years. Unfortunately, many of today’s structures are not living up to expectations.
To address and reverse this trend architects and structural engineers are increasingly adopting waterproofing systems and admixtures that have been proven to be effective in the protection of structure against water damage. However, it is important to understand that admixtures have classifications and not all admixtures are waterproofing admixtures. In fact, more than 90% of admixtures in the market are essentially concrete enhancing admixtures. Therefore in making the decision for specifying a waterproofing material for your structures it is important that you understand the facts below:
ACI Concrete Waterproofing Admixture Classification
According to American concrete institute the, most reputable concrete standard setting body concrete admixtures are classified into PRAH and PRAN. There is a huge misconception among professionals as to what it means for a structure to be waterproofed. Most admixtures such as plasticizers, superplasticizers retarders etc commonly misconstrued as waterproofing admixtures are concrete performance enhancing admixtures.
So the question is what does it mean for a structure to be waterproofed? When we say something is waterproof, we simply mean that liquid water will not pass through in any measurable amount under commonly found conditions. It is important to note that one of those commonly found conditions is relatively high hydrostatic pressure, such as what might be found at the bottom of a deep building foundation or in an underground tunnel. So, an effective waterproofing system must be able to withstand hydrostatic pressure.
Fortunately, the concrete waterproofing industry has since redefined their terminology. In fact, American Concrete Institute’s 212.3R-10 Report on Chemical Admixture document devoted Chapter 15 to Permeability Reducing Admixtures that outlines PRAH and PRAN classifications. Permeability Reducing Admixture–Hydrostatic Conditions or PRAH products reduce water penetration through crystalline growth or a polymer plug, can perform under hydrostatic pressure and are suitable for watertight construction.
Conversely, dampproofing admixtures are now referred to as Permeability Reducing Admixture–Non-Hydrostatic Conditions or PRAN. PRAN admixtures reduce water absorption by repellent chemicals (soap, oils) or partial pore blocking (fine particle fillers). These admixtures are not suitable for concrete exposed to water under pressure and cannot protect in the presence of hydrostatic pressure.
Waterproofing against hydrostatic pressure is an important distinction that set PRAHs apart from PRANs.
AQUAFIN-AQ100Pis classified as a PRAH admixture. It is an advanced integral crystalline waterproofing admixture for concrete structures.
AQUAFIN-AQ100P comes in concentrate and therefore yield is significantly more than the already mixed crystalline admixtures. AQUAFIN-AQ100P can be added to concrete during the batching process at the concrete plant or the construction site to a ready mix-truck with full mixing capabilities
If you like more details about waterproofing admixtures or if you like us to advise you on any waterproofing details for specifications purposes.
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