Reinforced Concrete is one of the most versatile and widely used construction materials on account of its constructability and durability. Its durability is severely affected, due to its inherent formulation. Even M30 Concrete has as much as 14-20% pore volume, not including air pores. Concrete contains these pores due to a generous addition of mixing water used to obtain a sufficient compactness and workability. Owing to these capillary pores, concrete is always pervious to water. For Durability, it becomes imperative to protect concrete from ingress of water and an effective solution is integral waterproofing using MC-Special DM, a solution offered by MC-Bauchemie. This form of protection/waterproofing becomes increasingly attractive for applications such as basement slabs, walls, lift-pits, underground pipes, tunnels, deep pile foundations, manholes, dams, water-retention structures, swimming pools, wet areas, cooling towers, etc.

MC-Special DM Integral Waterproofing
MC-Special DM is easy to use, either in the concrete batching plant or in a transit mixer at site. MC-Special DM should be added to the concrete after all other components of the mix have been added. Concrete should be mixed for atleast a minute after addition of MC-Special DM. Dosage is economical at 1% by weight of cement or atleast 3 kg MC-Special DMper m3 of ready mixed Concrete. Post addition of MC-Special DM to the concrete, the ensuing actions helps protect your concrete against water ingress.

1. Reduction of Capillary Pores: Special additives in MC-Special DM make the concrete more workable (increases slump) at the same w/c ratio or provide a reduction in w/c at the same workability levels. This property helps concrete achieve excellent compactability thereby reducing capillary pores.

2. MC's Revolutionary DySC® Technology: MC-Special DM uses special latent hydraulic and pozzolanic Nanoparticles to ensure densest packing in the cement matrix at the Nano scale. The cement matrix is therefore densified by a complex process called - Dynamic SynCrystallization (DySC®). The strength and impermeability of any cement-based material is based on hydration of the clinker components. MC-Special DM's Nanoparticles in the capillary pores act as additional crystallization seeds that lead to new C-S-H gels and crystal formation thus completing mineralization of the cavity structure.

At this phase, the crystallization continues to the surface of the cement grains, without affecting the pore gel solution. Over time the structure of the matrix is becomes refined, overall porosity decreases, micro-cracks are sealed and pore size distribution is optimized. In presence of external water ingress and existing calcium hydroxide in the pore space, this crystallization process accelerates, thereby filling up the pore cavities with the CSH gel and crystal hydration products. This mineralization process reduces further water ingress into the concrete.

3. Hydrophobic Pore Blocking Mechanism: In addition to reduction of capillary pores and the Dynamic SynCrystallization®, MC-Special DM has special additives, which on one hand causes contraction of capillaries and on the other hand converts the water-absorbing capillary forces into water repellant capillary forces due to the hydrophobic effect of the constituent. Thus water is pushed out of the capillary pores and the concrete is kept dry.

The result of these mechanisms has been verified in accordance with DIN 1048:Part 5: Testing water penetration into the concrete at varying pressure upto 5 bars. Results indicate that depending upon the concrete mix-design the water penetration under pressure is reduced by up to 60%. In addition, similar tests for co-efficient of permeability for concrete treated with MC-Special DM was reduced by up to 67% as compared to control concrete.

Therefore, with specialized Mix Designs and MC-Special DM, High performance waterproof can easily be envisioned for application into everyday construction.

NBMCW April 2014