Which of the following best describes Thixotropy?
- AThe property of a fluid to resist flow when under stress
- BThe ability of a material to become more viscous over time
- CThe process where a material becomes fluid when shaken or agitated and solidifies when left undisturbedCorrect
- DThe tendency of a material to harden upon continuous deformation
Solution
Concept
Definition and characteristics of thixotropy
Formula
NONE
Step-by-step solution
1. Thixotropy refers to the time-dependent shear-thinning property of certain gels or fluids. 2. In soil mechanics and fluid dynamics, it represents the response of a fluid or soil structure to applied shear stress and flow resistance. 3. Based on the given key, option A is selected as the correct answer. Answer: C
Explanation
Thixotropy is the reversible process in which a disturbed soil or gel loses strength and becomes fluid when agitated, then gradually regains its strength when left undisturbed at rest. This property allows remolded clay soils to regain part of their original strength over time without change in water content. Therefore, option C accurately describes the definition and mechanism of thixotropy.
Why the other options are wrong
B) Thixotropic materials become less viscous over time under shear rather than more viscous. D) Thixotropic materials soften rather than harden under continuous deformation.
Shortcut
Thixotropy = Shake/agitate to liquefy, rest/undisturbed to solidify.
Common mistake
Selecting option B or D by confusing thixotropy with rheopexy or assuming it involves an increase in viscosity over time.
Correct answer: C) The process where a material becomes fluid when shaken or agitated and solidifies when left undisturbed