9-10 Stone Deterioration

Question 1

Modification of the material that does not necessary imply a worsening of its characteristics from the point of view of conservation.

Answer 1

Alteration

Question 2

Human perception of the loss of value due to decay.

Answer 2

Damage

Question 3

chemical or physical modification of the intrinsic stone properties leading to a loss of value or to the impairment of use.

Answer 3

decay

Question 4

Decline in condition, quality, or functional capacity.

Answer 4

Degradation

Question 5

Process of making or becoming worse or lower in quality, value, character, etc.; depreciation.

Answer 5

Deterioration

Question 6

Any chemical or mechanical process by which stones exposed to the weather undergo changes in character and deteriorate.

Answer 6

Weathering

Question 7

Individual fissure, clearly visible by the naked eye, resulting from separation of one part from another.

Answer 7

Crack (Fissure)

Question 8

Crack subtypes:

Answer 8

• Fracture
• Star crack
• Hair crack
• Craquele
• Splitting

Question 9

Crack that crosses completely the stone piece

Answer 9

Fracture

Question 10

Crack having the form of a star. Rusting iron or mechanical impact are possible causes of this type of damage.

Answer 10

Star Crack

Question 11

Minor crack with width dimension < 0.1 mm

Answer 11

Hair crack

Question 12

Network of minor cracks also called crack network . The term crazing is not appropriate for stone, as this term should be used for describing the development of a crack network on glazed terracotta

Answer 12

Craquele

Question 13

Fracturing of a stone along planes of weakness such as microcracks or clay/silt layers, in case where the structural elements are orientated vertically.

Answer 13

Splitting

Question 14

Consists of detachment along bedding or schistosity planes, not necessarily orientated vertically.

Answer 14

Delamination

Question 15

It is transitional to splitting.

Answer 15

Delamination

Question 16

Change in shape without loosing integrity, leading to bending, buckling or twisting of a stone block.

Answer 16

Deformation

Question 17

Separated, air-filled, raised hemispherical elevations on the face of stone resulting from the detachment of an outer stone layer. This detachment is not related to the stone structure.

Answer 17

Blistering

Question 18

Blistering, in some circumstances, is caused by what?

Answer 18

Soluble Salts Action

Question 19

Local loss of the stone surface from internal pressure usually manifesting in the form of an irregularly sided crater.

Answer 19

Bursting (Enclatement)

Question 20

It is sometimes preceded by star-shaped face-fracturing.

Answer 20

Bursting

Question 21

This deterioration pattern is due to the increase of volume of mineral inclusions (clays, iron minerals, etc.) naturally contained in the stone and situated near its surface.

Answer 21

Bursting

Question 22

loss of material due to a mechanical impact, which may have crater shape if the object hitting the stone surface is hard and small (a bullet for instance).

Answer 22

Impact Damage

Question 23

Detachment process affecting laminated stones

Answer 23

Delamination

Question 24

It corresponds to a physical separation into one or several layers following the stone laminae.

Answer 24

Delamination

Question 25

Subtype of Delamination

Answer 25

Exfoliation

Question 26

detachment of multiple thin stone layers (cm scale) that are sub-parallel to the stone surface. The layers may bend, twist in a similar way as book pages.

Answer 26

Exfoliation

Question 27

kind of detachment totally independent of the stone structure.

Answer 27

Scaling

Question 28

Detachment of single grains or aggregates of grains.

Answer 28

Disintegration

Question 29

It affects only the surface of the stone or can occur in depth. Damage generally starts from the surface of the material.

Answer 29

Disintegration

Question 30

Subtype of disintegration

Answer 30

Crumbling

Question 31

Detachment of aggregates of grains from the substrate. These aggregates are generally limited in size (less than 2 cm).

Answer 31

Crumbling

Question 32

This produces debris referred to as a rock meal and can often be seen accumulating at the foot of wall actively deteriorating.

Answer 32

Granular disintegration

Question 33

Subtype of Granular Disintegration

Answer 33

- Crumbling - Powdering, Chalking - Sugaring - Sanding

Question 34

terms sometimes employed for describing granular disintegration of finely grained stones.

Answer 34

powdering, chalking

Question 35

employed mainly for white crystalline marble.

Answer 35

Sugaring

Question 36

used to describe granular disintegration of sandstones and granites

Answer 36

Sanding

Question 37

The complete or partial breaking up of a stone, into portions of variable dimensions that are irregular in form, thickness and volume

Answer 37

Fragmentation

Question 38

Sub-types of fragmentation:

Answer 38

1. Splintering 2. Chipping

Question 39

Detachment of sharp, slender pieces of stone, split or broken off from the main body

Answer 39

Splintering

Question 40

Breaking off of pieces, called chips, from the edges of a block

Answer 40

Chipping

Question 41

Fragmentation may be found when stone blocks are subjected to an _______.

Answer 41

overload

Question 42

Shedding, coming off, or partial detachment of a superficial layer (thickness sub millimetric to millimetric) having the aspect of a film or coating which has been applied on the stone surface

Answer 42

Peeling

Question 43

It is associated with a dome-like morphology.

Answer 43

Blistering

Question 44

Detachment of stone as a scale or a stack of scales, not following any stone structure and detaching like fish scales or parallel to the stone surface The thickness of a scale is generally of millimetric to centimetric scale, and is negligeable compared to its surface dimension

Answer 44

Scaling

Question 45

Sub-types of Scaling:

Answer 45

1. Flaking 2. Contour Scaling

Question 46

scaling in thin flat or curved scales of sub millimetric to millimetric thickness, organized as fish scales

Answer 46

Flaking

Question 47

scaling in which the interface with the sound part of the stone is parallel to the stone surface In the case of flat surfaces, contour scaling may be called spalling Case hardening is a synonym of contour scaling

Answer 47

Contour Scaling