Title:
Durability of Portland-Limestone Cement Pastes in Citric Acid (Prepublished)
Author(s):
Awetehagn Tuaum Gebremariam and Mahmoud Shakouri
Publication:
Materials Journal
Volume:
Issue:
Appears on pages(s):
Keywords:
acid attack; citric acid; organic acids; durability; microstructure; portland-limestone cement (PLC); ordinary portland cement (OPC)
DOI:
10.14359/51751742
Date:
5/21/2026
Abstract:
This work investigates the degradation of portland-limestone cement (PLC) pastes under citric acid exposure and compares the results with those for ordinary portland cement (OPC). Cylindrical specimens were exposed to 0.5 M citric acid for 42 days, and deterioration was assessed through mass loss, cross-sectional reduction, pore solution chemistry, and electrical properties. Results show that PLC experienced more pronounced degradation than OPC, losing nearly 95% of its initial mass and approaching substantial section loss by 42 days, compared with about 63% mass loss and partial section reduction in OPC. Bulk resistivity decreased steadily in both binders, while formation factor analysis indicated a rapid loss of pore connectivity in PLC. Phase analyses confirmed accelerated depletion of portlandite and precipitation of porous calcium citrate hydrates. These findings, obtained from neat pastes specimens under a controlled, upper-bound laboratory exposure, indicate that PLC is more vulnerable than OPC to citric acid and warrant exposure-specific durability assessments in material selection.