Evaluation of the Loss of Uniaxial Compressive Strength of Sandstones Due to Moisture

ABSTRACT

The reduction in uniaxial compressive strength (UCS) was investigated for sandstones under various moisture levels. Thirty-four UK Darney sandstone samples were tested under six different moisture conditions. The time-dependent moisture gain and loss were also evaluated. For 77 sandstones identified in the literature, the loss of UCS between oven-dry and saturated conditions was up to 45%, with an average of 20%. For Darney stone, the average loss of UCS was around 20%, with UCS around 72 N/mm² when oven-dry and 58 N/mm² when fully saturated. During saturation, significant loss of UCS occurred soon after exposure to water with 80% of UCS being lost within the first 2.5–6 hours. For Darney stone 50% of UCS was lost at air-dry conditions. Results from the 78 sandstone types were compared with the equivalent compressive strength defined by BS EN 772–1:2011 for oven-dry, air-dry, and saturated conditions. The estimated values by BS EN 772–1:2011 for dry and saturated UCS agreed well with the available test data and indicated a lower-bound solution. For immersed conditions, BS EN 772–1:2011, however, overestimates the reduction in UCS for a large number of samples and provides an average, instead of a lower-bound solution.

KEYWORDS:

• BS EN 772-1:2011
• sandstone
• saturation
• UCS
• Uniaxial compressive strength
• water content

Acknowledgments

The authors gratefully acknowledge the support of the University of Pécs, Hungary through the Thematic Excellence Programme Framework 2019 (TUDFO/51757-1/2019-ITM). The opportunity to use the Brunel University Civil Engineering laboratory facilities is gratefully acknowledged. The authors wish to thank Marcus Paine from Hutton Stone for his expert advice and providing Darney stone samples for testing. Further thanks to Sabrirajan Tamilselvam and Mihrab El-Fatih MSc students at Brunel University London for their excellent help with laboratory testing.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported by the Thematic Excellence Programme Framework 2019 [TUDFO/51757-1/2019-ITM].