In order to achieve the utilization of the recycled aggregate scientifically and technologically, two different techniques will be applied.
- The residual concrete as well as the CDW is a combination of mortars and aggregates. The adhered mortar will be partially removed. A certain amount of RCA is going to be exposed to heat treatment according to an established technique, in order to remove entirely the adhered mortar and determine its mass percentage. Then the RCA intended to be utilized in concrete mixtures will be added in a modified concrete truck mixer for various time intervals (determined based on the results). During this process, water is going to be added in order to remove and wash out smaller particles, dust and the weaker adhering mortar. This method, which resembles a prolonged Los Angeles test, is expected to decrease significantly the adhered mortar, and discard the weaker or fractured aggregates, keeping only the stronger and sounder ones. The treatment method is also expected to affect the shape of the aggregates by making them rounder.
- The second technique is the internal curing (IC) mechanism. This technique is going to be used on various mixtures, according to the RCAs absorption and desorption, in order to diminish the materials self-desiccation and drying shrinkage. The amount of IC water will be calculated based on the chemical shrinkage of the cement, the aggregates absorption, the aggregates saturation degree, the maximum expected degree of hydration and the cement quantity. It is expected that an effective IC agent will be able to carry the required water within the materials structure (sufficient absorption) and release a significant amount of water at high RH levels (pore size high enough). In addition, small trial mixtures were designed in order to assess their IC action in concrete.
Based on the above the scientific objectives are summarized below:
SO-1: To improve the properties of RCAs with the abovementioned techniques
SO-2: To produce RACs with at least similar durability and compressive strength ranges, with the normal concrete
SO-3: To use the produced materials to construct a small kiosk, within the plant land-lot, for demonstration reasons, which will be named as “green kiosk”.
SO-4: To elaborate a commercialisation plan for the 5 years after the end of this project