The Use of the Super Absorbent Polymer as Water Blocker in Concrete Structures

Abstract

Adding super absorbent polymer to the concrete mix improves the performance of the concrete in its both stages; fresh concrete and hardened concrete. The super absorbent polymer has the ability to absorb relatively large amount of water and convert it into gel at the same time the volume increases proportionally. The new modified concrete has the ability to retain water in the form of gel which helps in the internal curing process of the concrete at its early stages and helps in blocking the water flow through voids and cracks in the mass of the concrete at its later stages. This study focuses on the ability of concrete to block the water flow through the concrete cracks. Several samples were prepared with different amount of super absorbent polymer added to the concrete mix expressed in percentage with respect to the weight of cement. Several cylindrical samples were prepared, but three different samples will be presented in this study. The samples were intentionally broken into two pieces. The two pieces are then put together forming artificially induced cracks in the samples. These samples were subjected to water pressure; falling head and constant head. The water flow through the induced crack in the sample is measured. The effect of the super absorbent polymer on the water flow is monitored and compared with the control samples, which is the sample prepared with no admixtures. The water tightness leading to complete water blockage is studied. The short term effect as well as the long term effect of the super absorbent polymer on the concrete water tightness is also studied. Several amounts of the super absorbent polymer expressed in terms of percentages of the cement weight are used in order to shed the light on the water tightness property of concrete. The increase of the amount of the super absorbent polymer in the concrete mix improves the internal curing properties of the concrete at the same generate more voids in the mass of the concrete which in turn reduces the strength of the concrete. Optimum amount of the superabsorbent polymer should be considered if the focus is the concrete strength. Also, the increase in the amount of the superabsorbent polymer in the concrete improves the water tightness of the concrete, which makes the concrete capable of blocking the water flow through the concrete cracks. There are several advantages of adding the super absorbent polymer to the concrete mix, including improving the concrete plasticity and workability at the same time improving the concrete mix stability and pump-ability.