Strength properties of fresh and weathered rocks subjected to wetting–drying cycles

Abstract

Unlike previous research on soft and clay-bearing rocks, this study seeks to investigate the effect of wetting and drying (W-D) cycles on the engineering properties of two hard rocks. A series of W-D cycles were applied to fresh specimens of greywacke and basalt, and their strength, slake durability and density were progressively assessed as the number of cycles increased. It was found that unlike the basalt, the strength of greywacke rapidly decreased with increasing W-D cycles while the rock density and slake durability index remained almost the same. Analysis of the crack propagation in both rocks revealed that, compared to soft and clay-bearing material, the process of strength degradation in hard rocks was rather different, with a more pronounced effect of crack development. In addition, comparisons with the data obtained for the same type of rocks yet naturally weathered was performed to establish similarities between the properties of laboratory-deteriorated and naturally weathered rocks. The obtained results are expected to provide more practical values for such laboratory studies where the rate of rock deterioration is relatively high (several weeks) in comparison to what is commonly observed in the field (several years).

Compressive behaviour of fired-clay brick and lime mortar masonry components in dry and wet conditions

“…Clay-bearing rock strengths depend strongly on the weathering processes such as heating and cooling, wetting and drying, and freezing and thawing cycles [9][10][11]. A direct effect of moisture on such materials is the reduction in toughness due to particle swelling [12,13]. Saturated clay-bearing rocks were reported to have a compressive strength and elastic modulus up to about 90% of oven-dried counterparts [14].…”

Geotechnical Study of Raspadalica Cliff Rockfall, Croatia

“…The spacing between the joints for each joint set necessary to determine block volumes was determined using the Cloud Compare Distances tool, with which the distances in different cliff face zones were measured and analyzed. Although some developed remote sensing methods that have been successfully applied to identify other discontinuity features (separation, infilling, discontinuity wall roughness, and weathering grade) [83,86,[93][94][95][96][97] were used in the remote sensing survey of the Raspadalica Cliff, it was found that the resulting data had too much scatter and were not as reliable as the data obtained by in situ traditional geological and geotechnical surveys. Based on the statistical analyses of the data obtained from the 3D HRPC model of Raspadalica Cliff using the Cloud Compare software, the mean values of the orientations, discontinuity sets spacing and persistence for the total area of the Raspadalica Cliff are presented in Table 2.…”

Changes in shore platform wetting and drying cycles following the 2016 Kaikōura earthquake: Implications for incipient marine terrace evolution

“…At Kaikōura, the role of repeated wetting and drying is important because of the prevalence of mudstone, which is vulnerable to clay mineral disaggregation, microcracking, and a reduction of material strength (Dick & Shakoor, 1992; Gratchev et al, 2019; Hall & Hall, 1996; Wong et al, 2016; Yang et al, 2019). Within the intertidal zone, the platform surface is susceptible to wave action to pluck or wear away at the weakened material.…”

“…The most potent erosion agent is water, which controls mechanical and chemical weathering processes, as well as enhancing erosion through wetting and drying cycles (Hall & Hall, 1996). The loading and unloading of water associated with absorption and desorption can reduce rock strength, making it more vulnerable to denudation (Gökçeoglu et al, 2000; Gratchev et al, 2019).…”