New recycled concrete with high strength and improved shrinkage

New and innovative aspects

High-performance concrete is a type of concrete with high strength and durability thanks to its high cement content. Nevertheless, this high content of cement also implies that it has a high heat of hydration during setting and high shrinkage, in addition to low workability. Recycled concrete aggregate is a waste from the precast concrete industry that is characterized by its very high water absorption. Magnesium oxide (MgO) is a chemical compound that exhibits expansive properties when mixed with water. In addition, this expansion occurs during the concrete setting process and its production generates 70% less CO2 emissions than the manufacture of ordinary Portland cement.

The solution proposed by the researchers focuses on solving the existing problems in the traditional manufacture of concrete. The invention seeks to take advantage of recycled concrete aggregate and magnesium oxide to produce a sustainable, high-performance concrete optimal for structural use from the point of view of placement (high workability), from the point of view of strength (high strength) and regarding shrinkage (decreased shrinkage).

Main advantages of its use

• The sustainability of high-performance concrete is maximized by adding recycled concrete aggregate and reactive magnesium oxide as a secondary binder.
• The dumping of waste, clinker consumption and CO2 emissions are reduced and, with leads to the consequent reduction of climate change.
• The workability and strength of high-performance concrete made with recycled concrete aggregate and reactive magnesium oxide are simultaneously maximized.
• Minimizing shrinkage (shortening) of high-performance concrete and the cracking associated with this phenomenon is achieved by adding reactive magnesium oxide with expansive characteristics.

Specifications

The designed high-strength concretes are composed of type I cement (ordinary Portland cement) as the first binder and reactive magnesium oxide as the second binder in a content between 10% and 15% of the total binder mass of the high-strength concrete. The coarse aggregate fraction and the fine aggregate fraction are exclusively manufactured with recycled concrete aggregate. In addition to these components, the designed concretes also incorporate water and a superplasticizer admixture to increase the workability of concrete.

Applications

Potential applications are as follow:

• Construction and civil engineering sector
• Sector of new materials valid for structural applications
• Technical sector for the recycling and use of waste from the prefabrication industry

Intellectual property status

Protected by patent P202130466

Current development status

Developed exclusively in the laboratory and validated for industrialization

Desired business relationship

Commercial Agreement, License Agreement, Technical Cooperation: further development; Technical Cooperation: testing new applications; Technical Cooperation: adaptation to specific needs.