Earthen Architectural Heritage (Rehabilitate the earthen

construction in Saharan areas for sustainable development) Case

of Wilaya of Adrar M.Hamiane

1* ;I.Djefour

2 ;H.Merabet

3; D.Bouallala

4 ; A.Zekagh

5 ;Y.Turki

6; M.Saidi

7

1,2,3,7Materials Engineering department. URMPE, University of Boumerdes. Algeria

4BET Tarchid; Adrar Algeria.

5National Office of Management and Protection of Cultural Heritage. Algeria

6National Centre for Architecture in Earth. Ministry of Culture. Algeria

Abstract

The raw earth is a material used for millennia across all continents. Earthen architecture has

many benefits, not only in technical terms (thermal inertia), but also economic (less

expensive) and environmental (available and accessible on-site material, requiring no

transformation).Using recyclable materials to preserve natural resources, optimizing the

thermal inertia of buildings, and integrating renewable energy sources into the building

design or eco-construction are the guarantee of sustainable development. Sustainable

building should be a priority for construction policy in the south. This policy of sustainable

development in the Saharan regions of Algeria will meet the strong demand for housing,

preserve cultural heritage and contribute to reviving traditional knowledge to construction

ensure appropriate architecture to the needs of the population and to its economic resources

and climatic characteristics of the region, as well as the extension of the earthen heritage of

the builders. This objective is to guide our work. Developed and designed based on local raw

materials, mortars and coatings (plasters), are to be compatible with the historic building to

restore and ensure durability. The results of physical and mechanical characteristics of

mortar and coatings compositions developed at the laboratory level, showed effective,

compatible with the characteristics of construction materials building of the Adrar Hospital.

Keywords: Earthen construction, mortar, plaster, characteristic, formulation, Sustainable

development; Adrar Hospital.

1. Introduction

The earth is the simplest natural material we have

at our disposal. It is used by man in construction

for thousands of years to build buildings across all

continents, with techniques and traditions that are

a true living testimony to the history, cultures of

peoples, and the identity of places.

Algerian Sahara belongs to the world's largest

desert. It is the aridity that characterizes the

Saharan climate; water deficit at all levels is due to

the low rainfall, the intense evaporation, the high

temperatures and the high luminosity. Fig.1 Location of the Adrar hospital

Under these conditions we find the Adrar wilaya which is about 1540 km of Algiers (Fig. 1).

It is characterized by its relatively flat topography and desert geomorphology. In these areas

the man has developed construction techniques from the local earth which made the

transactions between the requirements of human life and the arid climatic environment. The

Adrar hospital (photo 1) our study case is located in the capital of the Wilaya. Its function is

to act not only as health care centre but also as preventive establishment and as a school of

health education. It was created in 1942, designed by French

architect of Belgian origin, Michel Luycks . It was built in

earth brick (adobe) and earthen mortar. These walls are carriers

roof composed of arches of different spans and heights. The

adobe (clay, sand and various additions) were made at quarries land outside the city of Adrar.

The building has been abandoned since the early 1980s, which marked its degradation. [1] Photo 1. The Adrar hospital Restoration of Structures of old buildings requires compliance their initial architectures and

knowledge of the characteristics of the materials used. To this end, our study aims to

characterize the building materials of the hospital, consisting primarily of

adobe and mortar. The analytical results will reconstitute identical

building materials and therefore a restoration, which is adequate and

compatible with the materials of

the monument. Sustainable building should be a priority for development

policy in the south. This policy of sustainable development in the

Saharan regions of Algeria will meet the strong demand for housing,

preserve cultural heritage and contribute to reviving the traditional constructive knowledge,

ensure appropriate architecture to the needs of the population and to the economic resources

and climatic characteristics of the region, as well as the extension of the earthen Photo 2. Infiltration of rain water heritage of the builders. It is this objective that guides our work. It is developed based on local

raw materials, mortars and coatings compatible with the historic building to restore and

ensure durability. The results of physical and mechanical characteristics of mortar

compositions and coatings developed at the laboratory level, showed effective, compatible

with the characteristics of construction materials of Adrar hospital.

[2,3]

2. Conservation status of the Adrar hospital

The earthen architecture has evolved through generations using local

materials. The earthen material has proven its validity through time, its

efficiency in architectural solutions, and the ability to appropriate design

against the influence of climatic and environmental factors.

It meets the needs of the population and their social, Photo 3 Erosion and loss of Mortars and adobes

cultural and economic development. Despite the advantages, strengths and the many features

that make the raw earth, which is the first building material in desert areas, other

disadvantages should be taken into account and improved to a more efficient use. The hospital

is in an advanced state of degradation. This inventory is accelerated in part by the action of

many natural factors: rain, moisture, temperature variation, and erosion .On the other hand, by

the disastrous consequences of actions and interventions of man on the monument.

Among the most important factors of degradation are visible on the monument, we note: the

infiltration of rain water, erosion and loss of mass

(bricks and mortars), stagnation of water on the

terrace, cracking walls and peeling of coatings.

Added to this, the activities that lead man on or

around sites such as:

Misuse of the site, the introduction of new

materials, poor waste management. The photos

from (1 to 4) show some types of these

degradations. [4, 5] Photo N° 4.1 &4.2.craks and peeling of

coating

3. Experimentation Eight (08) samples of mortars and coatings were taken for analysis .Samples was subjected

physical characterization, and analysis of mineralogical and chemical composition. The

flowchart in Figure 2 shows the methodology followed for these analyzes. The tests were

performed at laboratories CETIM, URMPE and ceramics laboratory at the University of

Boumerdes. The analysis results are shown in Tables 1 to 3.

Fig 2. The flowchart shows the methodology followed for these analyzes

Adrar Hospital

sampling

Jointing

Mortars

Coatings

(Plasters)

Characterization

Physical

Characterizatio

Mineralogical,Chimi

cal Characterization

- X-Ray

Diffraction

Analysis

- X-Ray

Fluorescence

Analysis

- M Specific density

- M Apparent density

- PH

- Free CaO

- Humidity

-Open Porosity

- Wall

- Terrace

- Vault

- Basement

- Internal

- External

- Hydrofuge

- Old Wall

layer

Table 1: Summary of physical properties of mortars and plasters samples from the Adrar hospital.

N° Sample Ms

(g/cm3)

Mv

(g/cm3)

H

(%)

PH CaOL

(%)

P

(%)

05 Wall Jointing mortar 2,44 2,01 2,02 8,97 4,48 17.62

06 Basement jointing mortar 2,34 2,15 1,66 8,97 + 8.12

07 Terrace jointing mortar 1,53 1,40 1,14 8,9 + 8.49

08 Vault jointing mortar 2,43 2,23 1,52 8,99 + 8.23

09

Wall old plaster layer

1st

layer 2,42 1,95 0,89 9,34 0,89 19.42

2nd

layer 2.32 1,95 1,14 / 1,14 15.94

10

Terrace plaster

1st layer 2,63 1,96 1,51 8,83 1,51 25.47

2nd

layer 1,58 1,30 0,80 8,73 0,80 17.72

11 outer plaster 2,43 1,92 0,64 10,3 5,6 20.98

12

internal plaster

1st

layer 1,58 1.20 / 9,01 / 24.05

2nd

layer 2,26 1,78 0,87 10,08 0,87 21.23

Legend: Ms: specific density; Mv: apparent density; H (%): Humidity; CaOL: Free lime; P: Porosity

Table 2: Summary of mineral compositions of plasters samples taken from the Adrar hospital

N° Composition internal

plaster

(First

layer)

outer

plaster

wall old

plaster

layer

01 Calcite + + +

02 Halite - - -

03 Anhydrite + - -

04 Gypsum - + +

05 Orthoclase + - -

06 Albite + + -

Table 3. The chemical

composition of plasters

samples taken from the

Adrar hospital

4. Interpretation

4.1. Sampling from the hospital Representative areas were selected for sampling (mortars and plasters). The main composition

of the samples is red clay, except plasters which show white, yellow and red light colors,

signifying the presence of lime, sand and some cement. Samples in their majority have low

porosity or pore with small white and black grains (sand) and sometimes the presence of

gravel, evidence that the raw material taken from quarries has not undergone purification or

sifting.

4.2. Chemical and mineralogical analysis of samples Plasters contains quartz , illite , calcite, gypsum or anhydrite , albite and kaolinite , which

show that both coatings ( old and internal ) are prepared from the raw material ( clay quarry)

with different proportions and additions Adrar sand.

07 Illite - - +

08 Kaolinite - - +

09 Quartz + + +

10 Dolomite - + -

11 Sepiolite - - -

12 Bassanite, high, syn - - -

13 Potassium tecto-

alumotrisilicate

-

-

+

14 Feldspar - + -

15 Aragonite - + -

N °

Sample'

s name

loss

on

ignitio

n (%)

Sum

of

conce

ntratio

n

(%)

SiO2

(%)

Al2O

3

(%)

Fe2O

3

(%)

CaO

(%)

Mg

O

(%)

SO3

(%)

K2O

(%)

Na2

O

(%)

P2O

5

(%)

TiO

2

(%)

01

Internal

plaster

(1st

layer)

12,15

100

58,05

7,44

3,89

10,67

2,17

1,50

2,31

0,96

0,05

0,8 0

02

Internal

plaster

(2nd

layer)

40,50

100

6,80

1,50

0,58

45,95

1,76

1,74

0,30

0,76

0,04

0,09

03

External

plaster

25,30 100 34,41 2,75 1,53 26,28 6,33 1,57 0,76 0,37 0,04 0,66

04

Wall

old

plaster

layer

9,76

100

67,69

5,73

2,86

8,62

1,50

0,73

1,73

0,66

0,03

0,67

The compositions of the raw materials of adobe, mortars and plasters wall is (80% sand and

20% clay) , basement (80% sand and 20% clay) , terrace (85% sand and 15% clay) , vaults (

87.5 % sand and 12.5 % clay).

4.3. Physical characteristics It is noted that the samples have a PH between (8.73 to 10.30), which shows the basic

character of the clay due to the mineralogical composition. All samples contained the free

lime, proof of presence of carbonate materials. The wall jointing mortar and the outer plaster

contain 4.48 % sequentially and 5.6 % of free lime, suggesting the addition of lime is used as

a stabilizer with clay. Open porosity of basement, jointing and vaults mortars varies between

(8.12 % and 8.49 %), which may explain a better state of conservation of basement and

some vaults adobes bricks and mortars.

The values of moisture samples are considered low (it is between (0.64 % and 2.02 %) , this is

due to that the samples were collected , stored, and then measured in an environment where

the temperature is high and the humidity is very low. We noted that the open porosity of

plasters decrease from the first layer to the last layer.

5. Conclusion. We note that the red clay main component of mortars and plasters is not highly plastic clay, it

does not contain montmorillonite. The red color is mainly due to the presence of iron oxide.

The approximate composition of raw materials used for the preparation of mortars, plasters

and adobes vary from (12.5 to 20% clay and 80 to 87.5 % sand). These are local raw

materials, taken not far from the monument and its surroundings. Basement mortars and

vaults have an open porosity between 8.12 and 8.49 %, which partly explain their

conservation. Terrace mortars have a porosity of 25.47 % for the first layer and 17.72% for

the second layer. Their damage or deterioration is due to storm water infiltration and damage

caused by these waters in the monument.

Mortars and plasters contain in their compositions: quartz, calcite, illite, gypsum or anhydrite,

which shows that the raw material is composed of local sand dune, red clay or their

combination and a percentage of sebkha substances. Mortars and plasters, also emphasize the

use of local raw material. Physical characteristics have enabled us to locate these materials in

relation to references and formulate compositions that have better performance.

A sustainable development means a development process that balances the ecological,

economic and social and establishes a virtuous circle between these three poles. Facing the

housing situation took an alarming proportion in Algeria and especially in the south and

causing a degradation threatening the quality of life of the population, earth is the material

that best satisfies this equation. A recyclable material, abundant, optimizes the thermal inertia

of buildings and preserves the traditional know-how and meets the need of housing in areas of

southern Algeria.

6. References

[1]Imane , D., Hafida,M . , Messaoud,H . , (2012), Design and characterization of adobes ,

mortars and clay plasters for restoration of the Adrar hospital, Boumerdes , Algeria . Magister

Thesis , University M'Hamed Bougara Boumerdes , p101 -233 .

[2]Bruno , P., (2005) , Earthen materials, Technical building and restoration (ed.), Eyrolles,

France , pp. 62-75 .

[3]Hugo , H., Hubert . G., (2006) Treaty of earthen architecture building, (ed.),Incidentally,

Craterre , France , P260 -289.

[4]Messaoud , H., (2011) , Expertise report of the hospital Adrar conservation .Algera.

[5]Djelloul , D., (2011) , Report of the Study Office of Adrar . (BET Tarchid ) .Algeria