DURABLE MORTARS OF A PORTUGUESE MILITARY STRUCTURE FROM THE XVITH CENTURY

Transcription

1 ICDS12 International Conference : from construction to rehabilitation For Your LOGO DURABLE MORTARS OF A PORTUGUESE MILITARY STRUCTURE FROM THE XVITH CENTURY DS 12 LNEC Lisbon 31 May - 1June 2012 Maria do Rosário Veiga - rveiga@lnec.pt António Santos Silva - ssilva@lnec.pt Martha Tavares - tavares.martha@gmail.com Ana Rita Santos - arsantos@lnec.pt IC Nádia Lampreia - nlampreia@lnec.pt LNEC Lisbon 31 May - 1June 2012 Case Study LNE C The Fortress of N. Sra. da Luz, located in Cascais coast. This Portuguese military structure, probably originally of the XVth century, has a trace witch is considered unusual in the Portuguese military architecture and was constructed within the program of construction of the defensive line of the coast. in: from Civitates Orbis Terrarum, of Georgius Braun It is one of the oldest monuments in the municipality of Cascais.

2 International Conference : from construction to rehabilitation Case Study - In 1488 the old Tower of St. António (Joanina Tower) was built by D. João II. - In 1580, this tower was transformed into a fortress with three Bastions. - With the 1755 earthquake of Lisbon, part of the structure of the fortress was damaged, including the Joanina Tower. The structure suffered major architectural transformations being surrounded by walls. Today, the fortress belongs to the Municipality of Cascais, who made a project of recovery and revitalization of the monument, with the objective to implement a museum. Characterisation of METHODOLOGY In Situ analysis Physical and Mechanical analysis X-ray diffraction analysis XRD Humidimeter Thermogravimetric and Differential thermal analysis TGA - DTA Microstructural analysis using the scanning electron microscope with energy dispersive X- ray spectroscopy SEM-EDS Wet chemical analysis Durometer hardness (Shore A) Ultrasonic test Compressive strength test Water absorption test

3 International Conference : from construction to rehabilitation Characterisation of METHODOLOGY In Situ analysis Humidimeter Durometer hardness (Shore A) Physical and Mechanical analysis ultrasonic test compressive strength test Water absorption test These tests main aim is to contribute to assessing the conservation status of renders and their functional capacity. Characterisation of METHODOLOGY X-ray diffraction analysis XRD Thermogravimetric and Differential thermal analysis TGA - DTA Microstructural analysis using the scanning electron microscope with energy dispersive X-ray spectroscopy SEM-EDS Wet chemical analysis These tests main aims are to determine the current composition of the mortars, in order to define the initial composition and their chronology, and evaluate the compounds of degradation in order to provide information about the mortars conservation state.

4 International Conference : from construction to rehabilitation The selection of samples was made according to LNEC methodology for characterization of mortars in ancient buildings. The importance of the different zones in terms of techniques and materials was taken into account. Joanina Tower (XV-XVI century) Interior wall 1 st coating systems Interior wall 2 nd coating systems NSL TJ1 I NSL TJ1 I NSL TJ1 E NSL TJ1 E Render mortar composed by four layers. The 1 st layer (interior to exterior) has brown colour and the 2 nd and 3 rd layers are white coloured (the 3 rd is stucco 1 mm thick). The last layer is a painting layer with ochre colour. Render mortar composed by three layers. The 1 st and 2 nd layers (interior to exterior) have white colour (the 2 nd is stucco). The last layer is a painting layer with ochre colour. 1 st layer mortar NSL TJ1 -I External surface NSL TJ1 -I painting layer stucco

5 International Conference : from construction to rehabilitation Joanina Tower (XV-XVI century) Interior wall 1 st coating systems Interior wall 2 nd coating systems NSL TJ1 I NSL TJ1 I NSL TJ1 E NSL TJ1 E Render mortar composed by four layers. The 1 st layer (interior to exterior) has brown colour and the 2 nd and 3 rd layers are white coloured (the 3 rd is stucco 1 mm thick). The last layer is a painting layer with ochre colour. Render mortar composed by three layers. The 1 st and 2 nd layers (interior to exterior) have white colour (the 2 nd is stucco). The last layer is a painting layer with ochre colour. painting layer stucco Internal surface NSL TJ1 -E External surface NSL TJ1 -E Joanina Tower (XV-XVI century) Interior wall 1 st coating systems Interior wall 2 nd coating systems The wall region with a hole NSL TJ1 I NSL TJ1 E NSL TJ2 Render mortar composed by four layers. The 1 st layer (interior to exterior) has brown colour and the 2 nd and 3 rd layers are white coloured (the 3 rd is stucco 1 mm thick). The last layer is a painting layer with ochre colour. Render mortar composed by three layers. The 1 st and 2 nd layers (interior to exterior) have white colour (the 2 nd is stucco). The last layer is a painting layer with ochre colour. Render mortar composed by a single and uniform layer whit white colour NSL TJ2

6 International Conference : from construction to rehabilitation Joanina Tower (XV-XVI century) Entrance zone wall (old door) Entrance zone wall (previously buried) NSL TJ3 NSL TJ4 NSL TJ3 Render mortar composed by three layers whit different colours: brown, yellow/ochre and white. Render mortar composed by two layers. The 1 st layer (interior to exterior) has brown colour and appears to be clay. The 2 nd layer has white colour and is rich in ceramic materials. Joanina Tower (XV-XVI century) Entrance zone wall (old door) Entrance zone wall (previously buried) NSL TJ3 NSL TJ4 Render mortar composed by three layers whit different colours: brown, yellow/ochre and white. Render mortar composed by two layers. The 1 st layer (interior to exterior) has brown colour and appears to be clay. The 2 nd layer has white colour and is rich in ceramic materials. NSL TJ4 1 st layer 2 nd layer

7 International Conference : from construction to rehabilitation South Bastions (XVIII-XIX century) Interior wall (with high humidity levels) NSL BS5 Render mortar composed by a single and uniform layer with white colour. NSL BS5 North Bastions Interior wall (small room) NSL BN6 XVIII-XIX century NSL BN7 XX century NSL BN6 Render mortar composed by a single and uniform layer with white colour. Render mortar composed by a single layer applied in three sublayers with white colour. NSL BN7

8 International Conference : from construction to rehabilitation Wall (XVII-XVIII century) South Wall NSL MS8 NSL MS9 Render mortar composed by a single layer whit white colour and painting Coating systems composed by four layers. Interior to exterior: light colour mortar (5mm), painting white ochre colour, light colour mortar and painting white ochre colour. NSL MS8 painting layer Wall (XVII-XVIII century) South Wall NSL MS8 NSL MS9 Render mortar composed by a single layer whit white colour and painting Coating systems composed by four layers (two system). Interior to exterior: light colour mortar (5mm), painting white ochre colour, light colour mortar and painting white ochre colour. NSL MS9 2 nd system 1 st system painting layer

9 International Conference : from construction to rehabilitation Wall (XVII-XVIII century) West Wall NSL MP10 Render mortar composed by a single layer with white colour and lime painting white ochre colour. NSL MP10 Results and Discussion painting layer CHEMICAL, MINERALOGICAL AND MICROSTRUCTURAL ANALYSIS From the analysis of test results performed it can be concluded that: The existing layers of paint and stucco (NSL TJ1-I, NSL TJ1-E, NSL MS8, NSL MS9, NSL MP10) are based on calcitic air lime. The pigment used in coloured layers is of mineral origin; painting layer stucco With the exception of NSL BS5 sample, that is of dolomitic air lime, all mortars have calcitic air lime as a binder; With the exception of NSL BN7 mortar sample, in all other samples the occurrence of pozzolanic reactions between lime and aggregates was detected, forming hydraulic compounds of calcium silicates. The use of fragmented siliceous sands, in particular quartz, feldspar and basalt, as well as the aggressiveness of the environment, and long reaction times were the main factors contributing to these occurrences;

10 International Conference : from construction to rehabilitation Results and Discussion CHEMICAL, MINERALOGICAL AND MICROSTRUCTURAL ANALYSIS From the analysis of test results performed it can be concluded that: The existing layers of paint and stucco (NSL TJ1-I, NSL TJ1-E, NSL MS8, NSL MS9, NSL MP10) are based on calcitic air lime. The pigment used in coloured layers is of mineral origin; With the exception of NSL BS5 sample, that is of dolomitic air lime, all mortars have calcitic air lime as a binder; Air Lime With the exception of NSL BN7 mortar sample, in all other samples the occurrence of pozzolanic reactions between lime and aggregates was detected, forming hydraulic compounds of calcium silicates. The use of fragmented siliceous sands, in particular quartz, feldspar and basalt, as well as the aggressiveness of the environment, and long reaction times were the main factors contributing to these occurrences; Results and Discussion CHEMICAL, MINERALOGICAL AND MICROSTRUCTURAL ANALYSIS From the analysis of test results performed it can be concluded that: The existing layers of paint and stucco (NSL TJ1-I, NSL TJ1-E, NSL MS8, NSL MS9, NSL MP10) are based on calcitic air lime. The pigment used in coloured layers is of mineral origin; With the exception of NSL BS5 sample, that is of dolomitic air lime, all mortars have calcitic air lime as a binder; With the exception of NSL BN7 mortar sample, in all other samples the occurrence of pozzolanic reactions between lime and aggregates was detected, forming hydraulic compounds of calcium silicates. The use of fragmented siliceous sands, in particular quartz, feldspar and basalt, as well as the aggressiveness of the environment, and long reaction times were the main factors contributing to these occurrences;

11 International Conference : from construction to rehabilitation Results and Discussion CHEMICAL, MINERALOGICAL AND MICROSTRUCTURAL ANALYSIS From the analysis of test results performed it can be concluded that: Siliceous sands from maritime origin, probably from the site, were used in all the mortars. Among the siliceous aggregates (predominantly quartz and feldspar), with exception of sample NSL TJ4 (2 nd layer), the use of basaltic aggregates was identified. The use of ceramic fragments in samples (NSL TJ1-E, NSL TJ4-1 st layer and NSL BN7) is also to be noticed; Some of the mortars show high levels of soluble salts, including chloride and sulphate ions. However, there was no evidence pointing out to microstructural phenomena of chemical degradation. Results and Discussion CHEMICAL, MINERALOGICAL AND MICROSTRUCTURAL ANALYSIS From the analysis of test results performed it can be concluded that: Siliceous sands from maritime origin, probably from the site, were used in all the mortars. Among the siliceous aggregates (predominantly quartz and feldspar), with exception of sample NSL TJ4 (2 nd layer), the use of basaltic aggregates was identified. The use of ceramic fragments in samples (NSL TJ1-E, NSL TJ4-1 st layer and NSL BN7) is also to be noticed; Some mortars showed high levels of soluble salts, including chloride and sulphate ions. However, there was no evidence pointing out to microstructural phenomena of chemical degradation.

12 International Conference : from construction to rehabilitation 1.0 kg/m 2.min 1/2 Results and Discussion CHARACTERIZATION OF MECHANICAL STRENGTH AND WATER BEHAVIOUR 6.2 kg/m 2.min 1/2 5.5 kg/m 2.min 1/2 6.5 kg/m2.min 1/2 NSL TJ2 (a), NSL TJ2(b) and NSL BN6 samples have the highest absorption capillarity coefficients (> 5.5 kg/m 2.min 1/2 ) and NSL TJ1-E and NSL BN7 the lowest values (< 1.0 kg/m 2.min 1/2 ). 0.4 kg/m 2.min 1/2 0.5 kg/m 2.min 1/2 Results and Discussion CHARACTERIZATION OF MECHANICAL STRENGTH AND WATER BEHAVIOUR 1.7 N/mm N/mm N/mm 2 The compressive strength of NSL TJ2 (a), NSL TJ2 (b), NSL BS 5 and NSL BN6 samples are reduced (< 1.7 N/mm 2 ); The modulus of elasticity shows a high deformability (E 1500 N/mm 2 ). 0.8 N/mm 2

13 International Conference : from construction to rehabilitation Results and Discussion CHARACTERIZATION OF MECHANICAL STRENGTH AND WATER BEHAVIOUR These results indicate that Joanina Tower, Walls and partly of North Bastions mortars are cohesive and are in good state of conservation. Conclusions -The N. Sra. da Luz fortress, built around 1580, was subjected to numerous interventions over the centuries.

14 International Conference : from construction to rehabilitation Conclusions -The N. Sra. da Luz fortress, built around 1580, was subjected to numerous interventions over the centuries. -The experimental analysis identified three groups of mortars, from different periods: Joanina Tower Conclusions -The N. Sra. da Luz fortress, built around 1580, was subjected to numerous interventions over the centuries. -The experimental analysis identified three groups of mortars, from different periods: Joanina Tower Wall

15 International Conference : from construction to rehabilitation Conclusions -The N. Sra. da Luz fortress, built around 1580, was subjected to numerous interventions over the centuries. -The experimental analysis identified three groups of mortars, from different periods: Joanina Tower Wall Bastions Conclusions The Joanina Tower mortars are constituted by: - Calcitic air lime and siliceous aggregates, mainly quartz with some altered basaltic grains. - Pozzolanic reactions between lime and aggregates were found in these samples, which showed good mechanical characteristics. These mortars are probably from XV th -XVI th century

16 International Conference : from construction to rehabilitation Conclusions The Bastions mortars were dated as the most recent in the Fortress. - The South Bastion mortar is constituted by dolomitic air lime. aggregate-binder interface filled with hydromagnesite These mortars are probably from XVIII th -XIX th century - The North Bastion mortar is constituted by calcitic air lime and siliceous sand (without basaltic grains) and it doesn t show any pozzolanic reactions. Probably from the XX th century Conclusions The Walls mortars are composed by calcitic air lime and aggregates with well distributed grain dimensions, mostly quartzitic but also incorporating altered basaltic grains. Pozzolanic reactions were detected but in a lower level compared with those from Joanina Tower. These mortars could date from XVII th or XVIII th century

17 ICDS12 International Conference : from construction to rehabilitation 12 LNEC Lisbon 31 May - 1June 2012 Conclusions The antiquity, durability and diversity of these mortars DS evidence their historical and technical importance. These facts, along with their general good condition, are the main reasons to recommend the preservation and IC conservation of these mortars. LNE C LNEC Lisbon 31 May - 1June 2012 The authors wish to thank The Câmara Municipal de Cascais (Cascais Town Council) for collaboration in this study, especially for all the information provided. The Fundação para a Ciência e Tecnologia (Portuguese Foundation for Science and Technology) for the financial contribution to this work, within the scope of Research Projects LIMECONTECH Conservation and durability of historical renders: compatible techniques and materials PTDC/ECM/100234/2008.

18 ICDS12 International Conference : from construction to rehabilitation For Your LOGO DURABLE MORTARS OF A PORTUGUESE MILITARY STRUCTURE FROM THE XVITH CENTURY 12 LNEC Lisbon 31 May - 1June 2012 DS THANK YOU for your attention Maria do Rosário Veiga - rveiga@lnec.pt António Santos Silva - ssilva@lnec.pt Martha Tavares - tavares.martha@gmail.com Ana Rita Santos - arsantos@lnec.pt LNE C IC Nádia Lampreia - nlampreia@lnec.pt