In
geotechnical engineering
Geotechnical engineering is the branch of civil engineering concerned with the engineering behavior of earth materials. It uses the principles of soil mechanics and rock mechanics for the solution of its respective engineering problems. It als ...
and
contact mechanics
Contact mechanics is the study of the deformation of solids that touch each other at one or more points.Johnson, K. L, 1985, Contact mechanics, Cambridge University Press.Popov, Valentin L., 2010, ''Contact Mechanics and Friction. Physical Pri ...
the term asperity is used to refer to individual features of unevenness (''roughness'') of the surface of a
discontinuity, grain, or particle with heights in the range from approximately 0.1 mm to the order of metres. Below the asperity level, surface interactions are normally considered to be a ''material'' property, arising from mechanisms of adhesion and repulsion at the atomic scale (often accounted for by ''material friction'', ''atomic friction'' or ''molecular friction'').
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Dilation
An often used definition for ''asperities'' in geotechnical engineering:
Unevenness of a surface are ''asperities'' if these cause dilation if two blocks with in between a discontinuity with matching ''asperities'' on the two opposing surfaces (i.e. a ''fitting discontinuity'') move relative to each other, under low stress levels that do not cause breaking of the ''asperities''.
Contrast with asperity in materials science
Materials science recognizes asperities
In materials science, asperity, defined as "unevenness of surface, roughness, ruggedness" (from the Latin ''asper''—"rough"), has implications (for example) in physics and seismology. Smooth surfaces, even those polished to a mirror finish, ar ...
ranging from the sub-visual (normally less than 0.1 mm) to the atomic scale.
See also
* Discontinuity (Geotechnical engineering)
* Geotechnical engineering
Geotechnical engineering is the branch of civil engineering concerned with the engineering behavior of earth materials. It uses the principles of soil mechanics and rock mechanics for the solution of its respective engineering problems. It als ...
* Rock mechanics Rock mechanics is a theoretical and applied science of the mechanical behavior of rock and rock masses; compared to geology, it is that branch of mechanics concerned with the response of rock and rock masses to the force fields of their physical env ...
* Soil mechanics
Soil mechanics is a branch of soil physics and applied mechanics that describes the behavior of soils. It differs from fluid mechanics and solid mechanics in the sense that soils consist of a heterogeneous mixture of fluids (usually air and wat ...
References
Further reading
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*{{Cite conference
, last1 = Szymakowski , first1 = J.
, last2 = Haberfield , first2 = C.
, title = Preliminary results of direct shear testing of large scale, jointed, soft rock
, book-title = Frontiers of Rock Mechanics and Sustainable Development in the 21st Century, Proc. ISRM 2001 - 2nd ARMS
, editor-last1 = Sijing , editor1-first = W.
, editor2-last = Bingjun , editor2-first = F.
, editor3-last = Zhongkui , editor3-first = Z.L.
, place = Beijing, China
, date = 11–14 September 2001
, pages = 257–260
, publisher = Swets & Zeitlinger, Lisse, Netherlands, Taylor & Francis
Taylor & Francis Group is an international company originating in England that publishes books and academic journals. Its parts include Taylor & Francis, Routledge, F1000 (publisher), F1000 Research or Dovepress. It is a division of Informa ...
, isbn = 90-265-1851-X
Building stone
Soil mechanics
Natural materials
Pavements
Road construction