In most every case of concrete degradation, the root cause of the issue is the presence of moisture or water within the concrete. The ingress of deleterious substances into concrete takes place through the pore system in the concrete matrix, or through microcracks. In order to effectively ensure a concrete structure’s durability, which leads to a longer lifespan and a more sustainable building, the concrete must first be effectively waterproofed.
Integral Crystalline Waterproofing
Integral Crystalline Waterproofing (ICW) prevents the movement of water through the concrete by plugging or blocking thenatural pores, capillaries and micro cracks, thereby making concrete its own waterproofing barrier. This stands in contrast to more conventional means of waterproofing, which usually involves applying a coating or membrane to the concrete surface. The process is sometimes also attempted through densification of the concrete. The ICW method of concrete waterproofing has been proven effective through successful use in virtually every country in the world.
ICW technology is based on principles that are very similar to the processes that occur during concrete hydration. When ICW products are added or applied to concrete, crystalline chemicals facilitate a reaction that causes long, narrow crystals to form, filling the pores, capillaries and hairline cracks of the concrete mass. As long as moisture remains present, crystals continue to grow throughout the concrete. Once the concrete has dried, the crystalline chemicals sit dormant until another dose of water (such as through a new crack) causes the chemical reaction known as crystallization to begin again.
The ability to reactivate in the presence of water gives crystalline-treated concrete the ability to improve self-sealing. When cracks form due to drying shrinkage, settling, seismic activity, etc., water entering through them causes new crystals to form and grow, blocking and filling the cracks. Improving the self-sealing ability of concrete is one of crystalline technology’s most unique and useful features, and can help to dramatically reduce the long-term maintenance and repair costs of a concrete structure.
Main Benefits of ICW
ICW contributes many beneficial properties to a given project, including:
PRAH vs. PRAN
A number of companies offer integral waterproofing products for new and existing concrete structures. These products have different chemistries and, more importantly, different levels of performance. When selecting Integral Crystalline Waterproofing products, it is important not to confuse them with:
These products are suitable for damproofing or above grade water repellency, but not suitable for below grade waterproofing applications.
An ideal concrete waterproofing system should:
Furthermore, the concrete waterproofing industry redefined their terminology a short time ago. In fact, American Concrete Institute’s (ACI) 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 are sufficiently able to resist water under hydrostatic pressure penetration and are suitable for watertight construction.
Conversely, damproofing 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 (densifiers). 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 sets PRAHs apart from PRANs.
Integral Crystalline Waterproofing is the future of concrete waterproofing worldwide. With sustainable building practices increasing in importance, and the lifespan of a structure intrinsically connected to this movement, a reliable waterproofing solution that will last for the intended life of the concrete structures becomes very important.
Source: Concrete Times