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LITERATURE REVIEW
The historic mine shafts have been collapsing and this is a major concern as far as public safety
is concerned. The collapse of majority of the shafts is attributed to the failure after deterioration
of the masonry materials which has been used for lining operations. In the construction of the
modern shafts, the provision of support is achieved mainly by the use of the concretes. The
analysis of the stability of the shaft would call for proper understanding of the properties of the
materials which has been used for the lining activities. The behaviour of both concrete and
masonry is considerably affected by the long term exposure to water depending on the
environment. It ids for this reason that the paper focuses on the effects of weathering on the
masonry constructed structures. The historical buildings have their structural skeleton made up
of stone bricks or clay bricks in some cases. In some cases they are made of the blocks which are
bonded with mortar so that a large variety of texture can be composed (Gentilini et al 2012).
The performance of the elements of masonry in terms of the structures has undergone evolution
during the previous years as large material science and technical knowledge reveals. In the
previous years, there has been development of different agents which are used in the bonding of
the bricks. In this particular long list, gypsum was the first one to be discovered in the period
around 2500 B.C. This was later followed by the lime water. In the present studies, there are
several additives which have been discovered and they make the modification of the physical
properties of mortar to be much easier. The presence of the ovens that have very large
capabilities of very high temperatures allows for the modification of the mortar’s special
properties.
Deterioration of Mortar through chemical Causes

Hydraulic Mortar Damage
Mortars are usually based on the pozzolanic components as well as hydraulic cement. They are
characterized by both the formation which is guided by hardening of two crucial substances of
the mixture. These mixture products include calcium silicates and calcium aluminates. These
particular compounds are known to be responsible for the long term as we’ll as short term
resistance of these components to pastes. According to their properties, they suffer from the
attack by sulphates in which the ion group plays major roles, SO4 2- ion. The SO4 2- ion is
usually capable of converting such kind of phases into the strength reduction as the crystals of
salts (Lanas, Sirera and Alvarez 2006).
The physical process resulting to masonry decay phenomena.
These processes as a result of freeze-thaw cycle affecting the geo materials those were there even
in the past in crucial works having the low porosity materials given. The salt attack vulnerability
is very subtle to porosity. This most occurred to the two masonry structures in the form of the sea
which is mostly affected by the wall face pulverization which may be slow process but cannot be
avoided since the process sine it results from salt crystallization brought about by wet breeze on
the wall face (McCabe, Smith and Warke 2007).
The external pores of every crystallization process are expanded and being filled up leading to
formation of detaching powder having no immediate effect. While the superposition of many
cycles within a long period may lead to a total disruption of both the mortar and bricks. This
pulverization is being suffered even by low porosity natural geo materials such as Moropoulou
and Theoulakis. The detailed of aging salt breeze impelling effect to the medieval masonry belt
of Rodi city which is made up of stones containing bio calcarenite.

The salt attack on the material of masonry can also result from the environmental modifications.
Therefore, the Holland next to the sea shore discussed the masonry walls deterioration.
Especially in this case, a number of flood from the sea within the low lands mate the
underground streams very salty. The rise of capillary in the water surface may result to salt
dissolution into masonry walls, this happen even if there is no contact with the breeze from the
sea. The most crucial thing in the cultural conservation is the case of the Venice. The major
building of Venice has provided a detailed analysis showing the ability as well as the Venetian
workmanship know-how of controlling the capillarity that rise from the foundation of a building
which is immersed inside the lagoon water. The Istria stones were used to build foundations as
well as basement of walls as per the selection of Venetian who has a need to understand the
knowledge of the role of the stone porosity (Franzoni et al 2014).
Figure 1: Showing the pattern of mortar decay as a function of the ions sources of sulphates.
Within this shield, masonry has been associated with low porosity (or high cooked temperature)
which brick up to a single meter above the level of the ground then the construction continues
using porous bricks which are fairly cheap. However, in the meantime, the level of the sea as
well as lagoon configuration changed, while the goth of tidal leading to flooding Venice that is

the ‘’Italian acqua atla’’ thus facilitating the rate of which the height is increasing with (Yavuz
2010)..
Whereby the Venetians construction system has been nullified with the outcome therefore the
rate of deterioration increase dramatically, so that MOSE one of the system known for closing
doors for lagoon embankment had not been achieved besides it long duration plan. The
discussion of phenomena of degradation is shown in the figure bellow. In the presentation of a
very heavy brick pulverization that the Castro Caro fortress undergoes. The detachment of the
plaster b the crystallized salt due to a high rise of capillarity within the interface is presented at
the center. The one on the right consist of spots of sodium sulphates are present in the bricks
surface within the Venetian wall caused by evaporation as well as wetting of water in form of
lagoon (Williams and Robinson 1981).
Salt crystallization within the porous material review
The crystals form in the pore of a brittle material may give out a huge pressure on the surface of
the pore having detachment to silver as well as other initiation of micro cracks. The most
dangerous salt is considered to be the sulphates and chlorides of sodium as far as clay bricks and
stones are put into consideration. The problematic factor is that it is very impossible to explain at
the level of micromechanical. The formation of the crystal is always due to change in relative
humidity, rate of evaporation as well the temperature, because to support which is not regular
causing the development crystal. The irregular nucleation occurring in a poor correlation towards
the phase leading to some changes to the controlled experiment next to the thermodynamic
equilibrium (Sass and Viles 2010)

Presentation of the main context that deliberates vulnerability of brick to salt weathering is done
as per the number of experimental evidences. Some scholars gauged the spore size distribution of
modern as well as medieval bricks by taking into account both the damaged together with units
in good conditions. Generally, the bricks with greater void content (eV > 40%) and of large
number of pores with an average diameter of ρp = 0.2 ÷ 2 μm are regarded as bricks highly prone
to deterioration. Units of the same family subjected to saline conditions during the experiment
process indicated a loss of mass within the range of ∆ m = 6% ÷ 15%.
A comparison of the available test results with a general agreement on the perceived features are
as indicated in the figure below. Information presented by the laboratory study defining specific
range of critical pore diameters ratify mass loss obtained from field study for the exposed walls
in Holland. An average porosity of p > 30% is realized from the reports presented by the two
studies. Volumes of voids that extend past this value are termed to be ongoing attack (Momeni et
al 2015).
Ultimately, it can be concluded that bricks pulverization concerning astronomical risk class
based on yearly reduction of wall thickness per annum is directly proportional to the time span of
temporal window whereby humidity as well as temperature venture into the critical ranges.

Figure 2: Distribution of pore size for mortars and bricks
The first discussion is on salt attack following the rise in water capillary, and is through the use
of data obtained from Venice building regarded to be a typical example, in which the nastiest
results on the surface of the wall is curbed within the strip of the wall with an oscillating water
head 1.2 + 0.2 m above ground surface. This is then followed by an explanation of weathering
process resulting from exposition of marine spray, through the use of decay survey indications of
Vanvitelli’s mole in Ancona, a detailed investigation is also involved in this particular case
concerning climatic changes impacts together with increase in air contaminated with different
species of chemicals (Papida, Murphy and May 2000).
VANVITELLI’S MOLE WEATHERING IN ANCONA
In this section, application of the available climatic parameters database in Ancona, an
evaluation has been conducted on the environmental condition frequencies bursting the trend of
decay of Vanvitelli’s brickwork over a given period from the time of completion of construction
process up to the present date. Proposals are currently suggested on evaluation of empirical laws
damage on brick as well as motor, and numerous information.

Installation of this military building was done in the year 1750 at a strategic place within the
artificial island of Ancona’s harbor, with a very strong masonry fortress wall building made of
units of clay bricks. The extensive contamination on air and the excessive exposition to sea
breeze along the neighboring harbor resulted into higher rates of degradation of the materials
used for construction thereby affecting the life of Mole. These phenomena indulged to convey
diffused interventions from the year 1860. During that particular time layers of the bricks were
already weathering and the withers of the motors used had pictures of cavities and losses
(Jayasinghe and Mallawaarachchi 2009).
It was up to the year 1980 when consideration of motor components along the depth was applied
following the completion of an extensive study conducted by scholars based on X-ray
diffraction. Analysis reports on the obtained results showed that cement motor occupied 25mm
of the external region while the contaminant of gypsum extended to 100 mm in depth. The
external region also comprised of particles of ettringite as the region is in access with carbon
dioxide and cold air, conditions that initiates the conversion of gypsum.
Figure 3: Samples of masonry wall decay caused by weathering process (Fookes, Dearman and
Franklin 1971)

A list of various zones without mortar repair is given in the work of a scholar by the name
Collepardi presenting a final average width loss for motor as an approximate of 20 mm. in the
year 1930, a natural calamity, great seismic shake occurred greatly impacting the degraded
regions, though were extensively reinstated. An extended repair on some parts of the destructed
zones were also conducted within the year 1970, drawing to a conclusion that there are even
shorter time intervals between one intervention work with another in lifetime of Mole, depicting
a significant increase in conditions that enhances degradation of chemo-physical factors in the
course of time (Verstrynge et al 2014).
This proposed study mainly attempts to give a clear distinctive relationship explanation on
factors of the climate like temperature T, Relative Humidity RH together with the perceived
chemo-physical degradation on materials. A linear regression technique is applied in determining
the extended variables for the entire lifetime (1750 - 1973) considering the available data within
the period of 1973 to 2010. A list is then created for the time windows comprising of climatic
states auspicious to crystallization of salt formation of thaumasite and ettringite (Ludovico and
Chastre 2012).
Conferring to average temperature per anum, the obtained values are within the range of 100 C to
13.3 0 C within 1750 and 1980, with an abrupt shoot to 15.5 0C in the year 2009. Relative
humidity however depicts a complex trend indicating an increase from 73.5% at commence of
the construction process to 80% by 1980, but at the final end, a great reduction to 72% is realized
in the year 2009 following the global warming effect. Such trend indications enable the
possibility of giving clear definition of reference values for the surveyed zones; the service life
mean temperature represented by TR was recorded to be 12.9 0C, while RHr, the mean relative
humidity was recorded as 79.68%.

Figure 4: Figure of Primordial wall study in Venice: distribution of pore size, compressive
strength of brick
The turning point for Ancona climatic evolution was marked to be 1980. By use of complete
meteorological data of bilinear distribution, it becomes a common knowledge that the effect of
global warming increases the periods facilitating the crystallization of salt while contrariwise
withstanding the formation of ettringite. With thaumasite, no matching is done for the formation
conditions at all and this closely proposes the observation made that there is no inferred chemical
indications realized within the recently completed mole surveys. The observation from the
experimental studies has shown that structures of masonry suffer greatly from a spectrum of the
phenomenon of aging. This results from chemical changes as well as stone mechanical
deteriorations (Benavente et al 2006).
The other components affected include mortars and clay bricks. The ambient conditions which
turn such effects as a consequence of the environment which is aggressive and suffers from the
increase of the pollution are treated as a requirement. In this chain, the key factor is the porous
characteristics of the materials which have been in use particularly in the traditional construction
industries. One of the effects which have been observed includes the brick pulverization, mortar

rendering and blistering (Ulusoy 2007). Despite the fact that the loss of mass in a single cycle is
small generally, the number of cycles per year as well as, the service life can sufficiently
superpose a noticeable deterioration. This finally leads to the promotion of the mechanical
damage due to stress concentration of the structure. The chances of preventing the aging
phenomenon is usually linked to the available data translation into the formulas for the analysis
which can later be integrated to be part of the entire system or included into the finite element
analysis. The presented problem is actually very crucial in the strategic preparation for the
protection of the heritage of the architecture.

REFERENCES:
Benavente, D., Linares-Fernández, L., Cultrone, G. and Sebastián, E. (2006). Influence of
Microstructure on The Resistance to Salt Crystallisation Damage in Brick. Materials and
Structures, 39(1), pp.105-113.
Fookes, P., Dearman, W. and Franklin, J. (1971). Some engineering aspects of rock weathering
with field examples from Dartmoor and elsewhere. Quarterly Journal of Engineering Geology
and Hydrogeology, 4(3), pp.139-185.
Franzoni, E., Gentilini, C., Graziani, G. and Bandini, S. (2014). Towards the assessment of the
shear behaviour of masonry in on-site conditions: A study on dry and salt/water conditioned
brick masonry triplets. Construction and Building Materials, 65, pp.405-416.
Gentilini, C., Franzoni, E., Bandini, S. and Nobile, L. (2012). Effect of salt crystallization on the
shear behaviour of masonry walls: An experimental study. Construction and Building Materials,
37, pp.181-189.
Jayasinghe, C. and Mallawaarachchi, R. (2009). Flexural strength of compressed stabilized earth
masonry materials. Materials & Design, 30(9), pp.3859-3868.
Lanas, J., Sirera, R. and Alvarez, J. (2006). Study of the mechanical behavior of masonry repair
lime-based mortars cured and exposed under different conditions. Cement and Concrete
Research, 36(5), pp.961-970.

Ludovico-Marques, M. and Chastre, C. (2012). Effect of salt crystallization aging on the
compressive behavior of sandstone blocks in historical buildings. Engineering Failure Analysis,
26, pp.247-257.
McCabe, S., Smith, B. and Warke, P. (2007). Sandstone response to salt weathering following
simulated fire damage: a comparison of the effects of furnace heating and fire. Earth Surface
Processes and Landforms, 32(12), pp.1874-1883
Momeni, A., Khanlari, G., Heidari, M., Bagheri, R. and Bazvand, E. (2015). Assessment of
physical weathering effects on granitic ancient monuments, Hamedan, Iran. Environmental Earth
Sciences, 74(6), pp.5181-5190.
Papida, S., Murphy, W. and May, E. (2000). Enhancement of physical weathering of building
stones by microbial populations. International Biodeterioration & Biodegradation, 46(4),
pp.305-317.
Sass, O. and Viles, H. (2010). Wetting and drying of masonry walls: 2D-resistivity monitoring of
driving rain experiments on historic stonework in Oxford, UK. Journal of Applied Geophysics,
70(1), pp.72-83.
Ulusoy, M. (2007). Different igneous masonry blocks and salt crystal weathering rates in the
architecture of historical city of Konya. Building and Environment, 42(8), pp.3014-3024.
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Williams, R. and Robinson, D. (1981). Weathering of sandstone by the combined action of frost
and salt. Earth Surface Processes and Landforms, 6(1), pp.1-9.
Yavuz, H. (2010). Effect of freeze-thaw and thermal shock weathering on the physical and
mechanical properties of an andesite stone. Bulletin of Engineering Geology and the
Environment, 70(2), pp.187-192.