Material Characterization and Condition Assessment Of Historic Wall Mortar At Poonch House, Lahore, Pakistan: Implications For Compatible Conservation

Povzetek

Poonch House is a late nineteenth-century colonial house in Lahore, Pakistan, and it is a very important but decaying specimen of hybrid Indo-European architecture. Its cloth has been subject to a series of declines bearing the effects of moisture, salt crystallization, and unsuitable replacement of lime mortars by Portland cement. This research is a thorough description of the original wall mortar so as to embark on coherent conservation measures. Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) was applicable to the representative samples to identify the various elevations and exposure conditions under investigation and analyze the data in order to establish the gravimetric moisture determination, X-ray diffraction (XRD), and in-situ ultrasonic pulse velocity (UPV) testing. The findings prove the presence of a lime-rich binder featuring an aluminous aggregate with broken brand pieces of bricks, which shows that there is a historical non-hydraulic lime mortar. SEM micrographs showed the existence of a porous and heterogeneous matrix with clear and specific grain boundaries and microcracking, and EDX spectra indicated trace salt contamination, as well as the presence of chlorine and silica. According to XRD analysis, calcite, quartz, gypsum, and halite were the main mineral phases, as evidenced by carbonation, sulfate attack, and salt crystallization. The moisture content (mean of 8.77 percent) is low (less than 1.0 km/s in degraded regions) and thus indicates that there is high microstructural weakening in the moisture-exposed regions. The aforementioned combination of microstructural, chemical, and non-destructive diagnostics can be presented as an evidence-based approach to the choice of compatible lime-based repair mortars and control over the deterioration caused by moisture. This study will add a regional model of scientific evaluation and conservation of South Asian colonial masonry heritage.