ABSTRACT
Advances in sustainability can be achieved by extending durability. Freeze and thaw damage is a major Source of degradation in limestone structures that causes crackmg and mcreased porosity. The mcrease in porosity tends to compromise durability further. Organic sealants used to curb the moisture intrusion are associated with ground level ozone production. In addition, the limited penetration of these compounds tends to cause freeze and thaw damage to occur deeper within the wall. This study investigated the application of reactive electrokinetic treatment to improve the strength and durability of limestone. The reactants in this case were sodium silicate and calcium hydroxide. Treatments were applied to vertical surfaces using novel re-circulating flow electrodes. A given treatment was applied for 12 days, during which sodium silicate was driven deeply into the limestone block from one electrode and calcium hydroxide from the other. The reactants met inside the stone and formed pore-blocking phases that increased the strength while reducing porosity. Freeze and thaw damage was induced within specimens in accordance with ASTM D 5312. The treatments prevented deterioration of porosity and strength. In other cases, the treatments appeared to reverse the effects of freeze and thaw damage. Some treatments yielded strength increases of 100% and higher.
