Laboratory simulation of salt weathering under moderate ageing conditions: Implications for the deterioration of sandstone heritage in temperate climates

Abstract

Salt weathering is a significant process affecting the deterioration and conservation of stone-built heritage in many locations and environments. While much research has focused on the impact of salt weathering under arid or coastal conditions with characteristic climatic conditions and salt types, many sites found to be experiencing salt-induced deterioration, such as sandstone rock-hewn cave temples in Gansu Province, China and sandstone buildings in the northern UK, experience high humidities, moderate temperature ranges, and different salt types.To evaluate the impact of salt weathering on sandstone-built heritage under such mild humid environmental conditions, a lab simulation experiment was designed.The experiment was carried out on three types of sandstone (used in the northern UK and Gansu Province, China) and utilized a realistic diurnal humidity and temperature cycle (85% RH/16 C + 60% RH/22 C), and three widespread damaging salts, that is, Na 2 SO 4 , MgSO 4 , and the mixture of Na 2 SO 4 -MgSO 4 . The nature and extent of deterioration was monitored by photography, weight loss, and the changes in petrophysical properties measured using hardness, ultrasonic pulse velocity (P-wave velocity), water absorption coefficient by capillarity, open porosity, and apparent density. All three sandstones were found to be susceptible to MgSO 4 and the mixture of Na 2 SO 4 -MgSO 4 , but weakly affected by Na 2 SO 4 under mild humid environmental conditions.

Differentiation Study of the Damage Characteristics of Rock Cultural Heritage Sites Due to the Sulfate Weathering Process

“…During periodic immersion and exposure to a given environment, mirabilite continuously precipitates, dissolves, regenerates, and migrates to the interior of the rock. The evolution process is illustrated in Figure 3 [22]. Furthermore, the hydrophilic minerals present in sandstone (such as calcite, albite, and microcline) and limestone (calcite) undergo complex physicochemical reactions, resulting in the detachment and loss of surface particles in the rock samples.…”

Diversity and Composition of Culturable Microorganisms and Their Biodeterioration Potentials in the Sandstone of Beishiku Temple, China

“…Bioweathering is a major threat to the preservation of such outdoor sandstone monuments at this site, and emergency management is necessary for sustainable conservation. Increasing attention has been paid to investigations of microbial communities using high-throughput sequencing (HTS), salt damage, and mineralogical analysis at this site lately [ 22 , 23 , 24 , 25 , 26 ]. By using both culture-dependent and culture-independent methods, a rich understanding of stone biodeterioration has been developed, making it possible to significantly advance knowledge on the compositions and metabolisms of epilithic microflora and specific biochemical processes [ 2 ].…”

The Crystallization Effect of Sodium Sulfate on Some Italian Marbles, Calcarenites and Sandstones

“…The effect of soluble salts has been known for centuries and has been widely studied [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] on porous building stones [17][18][19] and, in particular, on granitoids [20,21], limestones [22][23][24], sandstones [25,26], and travertines [27]. Different test methods have been used to explain and evaluate the crystallization process that damage rocks and, more generally, porous building materials [28].…”