Concrete is said to be the most commonly used man made materials in construction. All over the world, millions of cubic of concrete is being used every year.
Our discussion today is focused on how to make this most commonly used man made materials in construction last longer and more durable.
More often than not we are more concerned on how we can achieve a certain strength in concrete but we fail to pay attention or we pay less attention at what happens after 28 days that our concrete has achieve the targeted strength.
Concrete is a composition about 4 – 5 materials and they are; cement (binder), aggregate (granite), sand (silica), water and admixture. Good concreting starts from carefully selecting this materials. However, today I will be focusing more on water andits long time effect on concrete.
Water is very important in the whole concrete making process because the process of hydration is kicked started by introducing water into the matrix. Chemically, the amount of water required for hydration is between 18-22% by weight of cement. This indicate that to mix 50kg of cement you need minimum of 9ltrs and maximum of 11ltrs. Practically, we use between 20ltrs to 25ltrs to mix 50kg of cement. This excess variation brings about additional pores into the concrete which will adversely affect strength and durability of the concrete.
Porosity is defined as the intrinsic property of the material, measured in term of the amount of void space as percentage of the total volume. Porosity is a measure of void space in a material and is a fraction of the volume of voids (Vv) over the total volume (Vt) i.e (Vv/Vt). It can be expressed as a ratio (between 0-1) or as a percentage (between 1-100%).
Water reacts (hydrates) with the cement to create a hardened mass. Although it may not appear to be, concrete is a very porous and breathing material. It could be described as a “Hard Sponge”. The cement “portion of concrete (the matrix), although it only makes up 25% of the volume, determines most of the physical properties (strength and durability). It is also where a large portion of concrete problems originate from. One of the most critical components of good concrete is water. The amount of water determines porosity, strength, and other key properties of concrete. Typical water cement ratios (weight of water to weight of cement) range between 0.40-0.45. External elements begins to influence the concrete through permeability.
Permeability is defined as the ease with which something can navigate through the pores of a material. Thus, in addition to porosity, permeability will also depend on some factors such as the pressure of application, properties of the materials, e.t.c.
External materials can navigate through the concrete matrix only if there are pores in the concrete.
In certain cases, if there are water in the environment where we place our concrete, water flows easily into the concrete but if there is a pressure combined with the water (2 elements now water and pressure (hydrostatic)) then the water flows MORE easily. The ease is being defined or measured in the velocity of flows or the quantity of materials that flows per unit area per unit of time.
The concept of permeability has to be defined in term of either liquid permeability such as water or gaseous permeability such as ion, carbon dioxide, oxygen e.t.c.
Over the years research and technology has develop various ways to deal with the issue of porosity and permeability in concrete. For example, Chemical Admixtures such as plasticizers, superplasticizers and hyper plasticizers has been developed to reduce the amount of water up to 30%. Furthermore Mineral Admixtures such as Fly ash, Silica fumes, Pozzolanic ash, e.t.c has being introduced to enhance and densify concrete.
With advent of crystalline technology; concrete waterproofing and pore shrinkage has being made so easy. Aquafin Incorporation introduced the latest generation of crystalline technology after long years of research on concrete porosity and permeability. The common mistakes and construction flaws were all put into consideration, classified under controllable and non-controllable factors. Aquafin Admix and Betocrete series reduce this errors minimally and 100% takes care of porosity in concrete.
The working principles of Aquafin Admix makes such that during concrete hardening (hydration) Aquafin Admix forms billions of Nano crystals (a needle like-fibers) inside the concrete pores thereby reducing the concrete pore diameter thus blocking the flow of water through the capillary voids. The treated concrete is permanently watertight and yet breathable. Though the invention of Aquafin Admix totally erase water ingress into the concrete; concrete best practice such as right mix, placement and vibration must be duly observed for effectiveness.
Aqafin Admix is a reactive technology that remains an integral part of the concrete for the life of the structure, always reactivating whenever is exposed to moisture. Aquafin Admix can seal startic cracks up to 1/64’’ (0.4mm) that occur months or years after the concrete is hardened. However, environmental factors such as ambient, temperature, density of concrete, moisture and weather condition can affect the rate at which Aquafin Admix will seal the shrinkage cracks. This does not in any way affect it’s waterproofing capacity. Concrete treated with Aquafin Admix protects against rebar corrosion, spalling and weather related damages. See Aquafin Mortar LN for concrete repairs.
Aquafin Admix will not in any way adversely affect the strength of the concrete either in short term or long term bases but rather increases the compressive strength of your concrete by a minimum of 18% and makes concrete more durable thereby increasing life expectancy of the concrete by 40% or more.
Every claims made by Schomburg Germany and Aquafin incorporation can be independently verified.
For more information:
C/o Advanced Concrete Technologies Nig. Ltd.
2nd Floor, God’s Grace Plaza.
65, Allen Avenue. Ikeja.