Phyllite clays as raw materials replacing cement in mortars: Properties of new impermeabilizing mortars

• Published in: Construction & building materials Vol. 224; pp. 348 - 358
• Main Authors: Arce, Carolina, Garzón, Eduardo, Sánchez-Soto, Pedro J.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 10.11.2019
• Subjects: Additives; Consistency; Mechanical strength; Mortar; Permeability; Phyllite clays; Water retentivity; Additives; Mortar; Mechanical strength; Consistency; Permeability; Phyllite clays; Water retentivity
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2019.07.081

[Display omitted] •Phyllite clays replaced cement in mortars assessed as sustainable building material.•Increasing phyllite content decreases the apparent density of the new mortars.•Mechanical strength decreases proportionally to the amount of incorporated phyllite.•The new mortars have applications as impermeabilizing materials in construction. The aim of this investigation was to determine the suitability of phyllite clays as a raw construction material. For that purpose, the cement in mortars was replaced by a phyllite clay (0–90 wt%) making this study the first of its kind to be performed. These materials were prepared with different water proportions according to the water content and water/cement and water/binder (cement plus phyllite clay) relationships. A comparative study of the most important properties of the resulting experimental mortars was carried out, such as apparent density, water retentivity, consistency and mechanical strength (flexural and compressive strength), along with an evaluation of the pozzolanic activity and permeability. The results showed that the increase of phyllite decreases the apparent density, the consistency and mechanical properties of the mortar, while water retentivity fluctuates. Good correlations (R2 > 0.84) were obtained between flexural and compressive strength for the mortars after 28 days of curing. Pozzolanic activity was observed at cement replacement of 80 wt% of phyllite. Moreover, new impermeabilizing mortars constituted by phyllite clay and cement have been obtained according to the low coefficients of permeability. Taking into account the findings of this research, phyllite clays can be applied as raw construction materials with savings derived from replacing cement in mortars and the low energy consumption involved in their production. However, the present study concluded that the use of phyllite clays did not improve the mechanical strength of these new mortars but, in contrast, they can be applied for impermeabilization purposes in Construction and Civil Engineering.