Reverse Engineering of Historical Mortar and Plaster

- Ecofriendly Construction Materials -

Royal Botanic Garden1st Annual Scientific Day

Thursday January 12, 2012Amman, Jordan

Dr. Ayoup M. GhrairDr. Adi Said, Eng. Nailah al-Dawod,

Dr. Riham Miqdadi, Eng. Kamal Nuimat

Introduction• Natural and human factors have caused rapid

degradation in architectural heritage. As well as,some conservation projects at various historicalsites have had a negative impact on archaeologicalvalues because incorrect materials and techniqueswere applied during the conservation process.

• This project focuses on Reverse Engineering ofHistorical Mortar and Plaster to be used asecofriendly construction materials in greenbuildings and conservation applications.

IntroductionMortar types

- Lime mortar (hydraulic or non hydraulic) is one of theoldest known types of mortar, dating back to the 4thCentury BC and widely used in Ancient Rome and Greece

- Gypsum mortar is common to Ancient Egyptianconstruction

Plaster types- Lime plaster

- Gypsum plaster

Objectives• Study the composition of original mortars and

plasters to reconstruct their recipes

• Develop duplicate mortars and validate theirapplicability in the laboratory and on-site tests

• Establish standard specifications for mortars ofeach site

• Establish a permanent conservation team andtrain workers group from the local community intraditional mortar and plaster techniques

Collection of Samples

Al-Tuba Palace

Mshash cistern, inner face and outer face plaster.

Mar-Elias Church

and Ajloun castle

Figure 1. Mshash cistern, inner face plaster

Figure 4. Al-Tuba castle, anhydrous gypsum mortar

Figure 3. Different colors of fired bricks Mar-Elias Church southwells

Figure 2. Mshash cistern, infilling mortar

Petrographic Study

XRD Mineralogy study

Figure 1. XRD Spectra for Mar-Elias Church, well plaster.

Figure 2. XRD Spectra for Al-Tuba castle, upper part mortar

Figure 3. XRD Spectra for Al-Tuba castle, lower part mortar

Figure 4. XRD Spectra for Mshash castle, outer face plaster.

Table 1. Picking minerals under anoptical microscope

Inclusions

Inner layer

Plaster %30

Outer layer

Plaster %29

Grog 15 46

Aggregate 57 19

Lime 25 35

Charcoal 0.3 0.2

Quartz (Sand) 3 0.1

Total 100%

Table 2. Chemical analyses of total elements, acid soluble elements, losses at various temperatures for plaster and mortar samples

Element

(%)

Al-Tuba Castle

Lower part

Mortar

25

Al Tuba Castle

Upper part

Mortar

28

Mar-Elias church

wells plaster

24

Mar Elias

Church

Grave yard

Plaster

31

Mshash Cistern

Outer face

Plaster

29

Mshash Cistern

Inner face

Plaster

30

SiO2 7.06 19.11 17.3 6.65 19.58 16.70

Al2O3 1.19 2.10 4.23 0.80 3.73 2.12

Fe2O3 0.48 0.91 1.23 0.27 1.00 1.11

TiO2 0.09 0.19 0.28 0.19 0.21 0.20

P2O5 1.86 1.13 0.10 -- 0.37 --

CaO 34.24 32.78 39.72 49.60 43.19 42.65

MgO 0.56 1.23 0.6 0.43 0.64 0.80

Na2O 0.06 0.0 0.07 1.48 0.06 0.09

K2O 0.13 1.35 0.11 0.11 1.81 1.93

SO4 26.02 3.35 0.74 0.91 2.54 0.90

Loss at 105oC 0.91 5.58 1.12 1.34 0.89 1.12

Loss at 250oC10.84 5.74 2.26 1.59 1.71 1.80

Loss at 500oC15.50 16.39 6.84 4.02 4.72 5.22

Loss at 650oC20.13 28.45 17.45 15.57 17.80 14.20

Loss at 1000oC 22.73 35.36 36.03 39.03 33.09 34.32

Expected Outcome

By the end of the time framework designed for thefirst phase of this research, the following results areto be expected:

• Establishment of standard specifications for themortar of each site

• Durability and improved efficiency in repairingmortars in our architectural heritage

• Creation of a fully trained restoration team

Conclusion and Outlook

Mixes Lime Grog Gypsum Aggregate Sand Carbon&Ash

Mix 1 15 5 60 10 5 5

Mix 2 25 10 0.0 15 45 5

Mix 3 30 15 0.0 40 10 5

Mix 4 Will be designed

Mix 5 Will be designed

Proposed mixes of various materials estimated from the chemical analyses of total elements, acid soluble elements, losses at various temperatures and material balance calculations.

The final evaluation of the mortar and plaster will be done based on Bottger (1997), Knofel and Huesmann (1993) and Omeri (2009).)

Compressive strength ≥ 1.5 N/mm2

Tensile strength > 0.2 N/mm2

Elasticity modulus < 10 N/mm2

Water absorption < 10 kg. m-2.h-0.5

Thank you for your attention.