Discover the characteristics & examples of aluminium use in construction projects with low density, corrosion resistance, & optimal shape of profiles. Discover aluminium alloys 3103, 3105 (sheets), 5005, 5083, 5085, 5754 (sheets), 6005A, 6060, 6061, 6063, & 6082 with construction aluminium scrap.

Construction aluminium application

The properties of aluminum that make it a valuable material in construction industry are:

• low density;
• high corrosion resistance;
• the ability to obtain the optimal shape of profiles by aluminium extrusion.

Examples of aluminium use in construction are [1]:

• mobile military bridges;
• window and door frames;
• fences and railings;
• ship ladders;
• greenhouses and conservatories;
• cladding of building facades;
• enclosing façade structures;
• flagpoles;
• mobile and overhead cranes;
• stairs;
• automatic doors;
• road sign supports;
• electrical supports.

Construction aluminium: Eurocode 9

The majority of aluminium alloys used in construction are wrought alloys, in particular alloys of the 5xxx and 6xxx series. The most commonly used construction aluminium alloys here are:

• 3103, 3105 (sheets),
• 5005, 5083, 5085, 5754 (sheets),
• 6005A, 6060, 6061, 6063 and 6082 (extruded profiles).

Most aluminium products in this segment began to be used quite recently, and their service life is quite long – usually 20 years, and often 50 years. Therefore, the share of old aluminium scrap from the construction industry is gradually increasing: from zero in the late 1990s to 10-15% in the 2010s.

Harmful impurities in construction aluminium scrap

Sources of harmful impurities and potential pollutants contained in aluminum construction scrap are [1]:

• ceramic materials, including brick, concrete and glass;
• organic decorative and protective coatings;
• dirt and paint;
• polymers, including plastic and rubber;
• steel parts, including those attached to aluminum.

Dismantling of façade aluminium structure

Since the 1970s, a huge number of buildings with aluminium curtain wall facades have been built around the world. Many of these buildings are currently undergoing major renovations or demolition. Due to their design, aluminium facade structures can be easily dismantled and almost completely returned for re-melting. Building envelopes such as curtain walls, windows and doors are typically made from 6060 and 6063 aluminium alloys.

Figure 1 – Construction aluminium scrap [2]

The efficiency of recycling construction aluminium scrap from the dismantling of aluminum facades is demonstrated in the “case” of the European Aluminium Association [2]:

• In 2020, the outer shell of the office building was dismantled.
• According to the design documentation, the external aluminium structures of the building contained more than 28 tons of aluminium:
  – facade structures: extruded aluminium profiles from alloys 6060 or 6063
  – wall cladding: sheet aluminum from aluminium alloys of the 3xxx series
  – building canopy: most likely, sheets of 5xxx series alloys.
• As a result of dismantling the outer shell, 98.3% of the total weight of the aluminium structures were collected and sent for remelting to produce new aluminium products (Figures 3 and 4).

Figure 2 – Dismantling of aluminium building structures [2]

Figure 3 – Collection of construction aluminium scrap at the construction site [2]

Figure 4 – Sorting and processing of construction aluminium scrap [2]

Collecting aluminium building structures and products that have reached the end of their useful life is very important as this allows this valuable aluminium scrap to be recycled into new aluminium products. This also ensures a reduction in waste from the construction industry, which, for example, in Europe, constitutes the largest “garbage” stream by weight [2].

Sources:

1. Mark E. Schlesinger, Aluminum Recycling, 2017
2. EUROPEAN ALUMINIUM