Investigation of Physical-Mechanical Properties and Microstructure of Mortars with Perlite and Thermal-Treated Materials

• Published in: Materials 2024-07, Vol.17 (14), p.3412
• Main Authors: Saca, Nastasia, Radu, Lidia, Stoleriu, Stefania, Dobre, Daniela, Calotă, Răzvan, Truşcă, Roxana
• Format: Article
• Language: English
• Subjects: Cement; Cement hydration; Compressive strength; Demolition; Electric properties; Energy consumption; Flexural strength; Heat conductivity; Heat transfer; Investigations; Mechanical properties; Microstructure; Mortars (material); Perlite; Portland cements; Substitutes; Temperature; Thermal conductivity; Water absorption
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma17143412

This study aimed to obtain and characterize a mortar with perlite aggregate and thermal-treated materials that could substitute for Portland cement. First, the thermally treated materials were obtained by calcinating old Portland cement (OC-tt) and concrete demolition waste (CC-tt) at 550 °C, for 3 h. Second, plastic mortars with a perlite: cement volume ratio of 3:1 were prepared and tested for water absorption, mechanical strength, and thermal conductivity. The microstructure was also analyzed. Portland cement (R) was partially substituted with 10%, 30%, and 50% OC-tt. Thermal-treated materials negatively influenced the compressive and flexural strengths at 7 and 28 days. With an increase in the substitution percentage to 50%, the decrease in the compressive strength was 40% for OC-tt and 62.5% for CC-tt. The presence of 10% OC-tt/CC-tt positively influenced the water absorption. The thermal conductivity of the tested mortars was in the range of 0.37-0.48 W/m·K. SEM analysis shows the expanded perlite pores remained unbroken.