Durability properties of structural concrete containing very fine aggregates of marble sludge

• Marble industry waste can represent as much as 80–90% of the total extracted material.
• Marble sludge can be used in the production of structural concrete.
• The performance of these modified concrete is highly dependable on the superplasticizer type and content.
• Modified concrete was tested for various durability-related properties.
• The mix with 20% marble sludge and superplasticizer had equivalent performance to the reference mix.

In terms of volume, the ornamental stone extraction industry represents a great waste source. For example, in the marble industry, waste can represent as much as 80–90% of the total extracted soil and stone. In order to use the material resulting from stone cutting, three concrete families were produced to be tested for their durability capacity: the first one contains no superplasticizer, the second one a current plasticizer made with a mixture of organic polymers (SP1) and the third a high-performance superplasticizer, made with a combination of modified polycarboxylates in an aqueous solution (SP2). In each concrete family, four substitution ratios were used representing, by cement volume, 0%, 5%, 10% and 20% of marble sludge.During the experimental campaign, the aggregates were characterized in terms of water absorption and particle density, size grading, loose bulk density and voids content, Los Angeles wear, and shape index. The tests performed to characterize the marble sludge were sieve analysis, Blaine’s specific surface, particles density and mineralogical and chemical compositions. The mixes produced were characterized in terms of workability and bulk density in the fresh state. In the hardened state, compressive strength, water absorption by capillarity and immersion, carbonation, chloride penetration and shrinkage were assessed.This research showed that the durability characteristics of concrete get worse as cement content increases and marble sludge content increases. However, for the 5% and 10% incorporation ratios, these losses were insignificant. Superplasticizers’ incorporation was beneficial to concrete’s performance. In particular, the high-performance superplasticizer led to results in the concrete with less 20% cement content similar to those of the reference concrete without admixtures.