How Concrete Goes Bad

  • How Concrete Goes Bad


    It’s Porous

    Somewhat surprisingly, concrete is porous. While it is very hard, it also has millions of
    tiny pores and microscopic cracks. Looking at concrete under magnification reveals the
    pore and capillary structure, and it is remarkable how many tiny voids there are.
    There are a number of ways that concrete gets damaged and destroyed, but by far the
    most common and widespread are salts and freeze/thaw cycles.

    Salt and Water Get in the Pores and the Destructive Process Begins

    Salts, chemicals like fertilizers, and freeze/thaw cycles compromise concrete.
    Salt gets carried into the pores of the concrete by water and creates an acid-like reaction
    inside the concrete, eating away the bonds in the cement portion of the concrete, and
    creating voids that attract more water and salt. Salt is hydroscopic, which means that it
    attracts water, up to 10% more water in the same space. Water is the real catalyst of
    damage. Salt just makes it easier for water to get into the pores of concrete.
    When water gets absorbed into the pores, it can expand up to 9% when it freezes. This
    pressure creates cracks and larger voids in the interior structure of the concrete, creating
    pathways for water and chemical intrusion. Sooner or later, the pressure from freezing
    water will pop the surface of the concrete, exposing the aggregate, and creating an
    unattractive look and a potential safety issue.

    Poor Installation Makes Concrete Vulnerable to Damage

    Engineering concrete is a lot more complicated than one might think. A lot of attention is
    paid to curing conditions, but most of the damage to concrete is started when the mixture
    is made. Concrete contains 3 basic ingredients: Portland cement, rocks (aggregates), and
    water. The proportions of these ingredients are critical to the strength and performance of
    concrete. If these proportions are off, even a little bit, concrete is weakened and durability
    is compromised.
    The most common mistake made with concrete is adding too much water to the mix to
    make it easier to work. Too much water weakens the concrete and creates a pore structure
    that is large, easily accessed, and lacking durability. The use of water-reducing
    admixtures (plasticizers) in the mix allows one to have a workable mix while using the
    appropriate amount of water to get strong and durable concrete.
    Unfortunately, even concrete that is mixed and placed correctly can be compromised by
    salt, chemicals, and freeze/thaw cycles. It just takes longer to damage properly mixed and
    placed concrete.
    The key to protecting your concrete is to first have properly mixed and placed concrete,
    and then to prevent salts and water from entering the concrete. CreteDefender P2
    permanently prevents salts and water from entering the concrete.