Lime burning tradition in field kilns : a case study of the Jämtland tradition in Sweden
This study focuses on the local lime tradition in the region of Jamtland, in central Sweden. Local lime was used when building the medieval stone churches and since they are in a need of restoration there is subsequently a need for understanding the use of local lime. The geology of Jamtland contains several layers of limestone in the folded mountains. There is a broad spectrum ranging from pure Silurian limestone to clay containing Ordovician limestone, giving all kinds of lime from pure air lime to strong hydraulic lime. The preserved historic mortarshave mostly been made with the hydraulic lime. Several old field kilns have been preserved in the forest landscape as prehistoric monuments, showing the model of the local lime burning tradition. This paper discusses the process of identifying the historic lime kiln constructions and their burning technique. It also describes the process of slaking this hydraulic binder in order to produce a lime mortar with workability and compatibility required from a restoration mortar. Newly-produced samples of lime mortar have been compared with historic ones in thin section microscope for further understanding.
Hydrauliskt kalkbruk Produktion och användning i Sverige vid byggande från medeltid till nutid.
This dissertation in its entirety, i.e. this publication prepared for a doctorate and now presented together with the licentiate thesis from 2004, deals with the production and utilisation of hydraulic lime mortar, including natural cement and pozzolana mortar, in historic buildings in the Nordic countries, especially in Sweden, from the Middle Ages until present time. The disseratation covers a field of knowledge where the collected knowledge still is meagre. There was a historic stage in a general endeavour to produce mortar with hydraulic characteristics, which also led to the development of Portland cement. The author is of the opinion that such an endeavour has existed for a long period; in Sweden at least since the 18th century. This is investigated with and supported by a survey of the production and utilisation of hydraulic lime mortar and also natural cement and pozzolana mortar through the course of time. 
 
Two investigations are included in the licentiate thesis. The first deals with the situation concerning knowledge and research with regard to the production and utilisation of hydraulic lime, hydraulic lime mortar, natural cement and pozzolana mortar from a historical perspective. The second deals with the occurrence and deposits of limestone that has been possible to utilise for the production of natural hydraulic lime; and similarly the raw materials for production of natural cement and pozzolana mortar, for instance brick for brickdust lime mortar and burned alum shale for alum shale lime mortar. 
 
The production of lime and other materials is linked in this dissertation to still existing buildings and constructions. This study includes a detailed presentation of composition, material properties and also production. This is achieved by four sub-surveys covering four types of mortar: (1) natural hydraulic and sub-hydraulic lime mortar, (2) natural cement, (3) brickdust lime mortar and (4) alum shale lime mortar. The intention is to characterise and illustrate by the four sub-studies investigations for what purposes these materials have been used, i.e. in what objects, with application as mortar, grout and finishing mortar, or in the manufacturing of facade ornaments for example. Natural hydraulic and sub-hydraulic lime mortar was in use already during the Middle Ages. However, the conditions dealt with in this dissertation refer mainly to the latter part of the 17th century and the 18th, 19th and 20th centuries. In contrast natural cement was in use during the 19th century only. 
 
The investigations included in this doctoral dissertation are based on own and other available building-archaeological investigations and observations and also mortar studies. The building investigations were made in connection with restoration projects and facade restoration. The mortar investigations consist of quantitative and qualitative microscopic analyses of thin section as well as chemical analyses and to some extent also SEM/EDS and XRD analyses. The large number of thin section analyses and chemical analyses, and the large number of analysed components, is unique for the investigations of hydraulic lime mortar in Sweden. The analyses thus provide completely new information regarding these kinds of mortars. 
 
This study demonstrates that hydraulic lime mortar is a traditional building material that has had an essential role in buildings in Sweden from the Middle Ages to present time. A lot of lime mortars from before the 17th century are sub-hydraulic according to this investigations. During second half of the 17th century the knowledge about hydraulic mortar was developed. At that time could the hydraulic effect rise and 1770 the swedish cement, the alum shale mortar, was devised. 
 
Title in English: 
HYDRAULIC LIME MORTAR 
Its Production and Utilisation in Sweden in Buildings from the Middle Ages until present Time. 
 
Title in Swedish: 
HYDRAULISKT KALKBRUK 
Produktion och anvandning i Sverige vid byggande fran medeltid till nutid. 
 
Language of original text: Swedish with a summary in English. 
Part I: Printed dissertation: 333 pages, 5 figures, 11 tables, bibliography. 
Part II: DVD catalogue: 360 pages, 1 appendix, 357 figures, 11 tables. 
Licentiate thesis: Part I: Printed thesis: 173 pages, 10 figures, bibliography. Part II: CD catalogue: 247 pages, 2 enclosures
Mechanical behaviour and durability of high volume fly ash cementitious composites
The purpose of this research is to separate different morphological particles of ASTM class F fly ash, and study their effect on mechanical behaviour and durability of high volume cementitious mixtures. In this research wet separation of raw fly ash is carried out, which resulted in three layers of different morphological particles. The first layer of particles float, comprise of about 1-5% of fly ash, is identified as cenospheres or hollow spheres. The second layer of particles is measured to be 55-60% of raw fly ash and consisting of porous spherical and rounded particles rich in Si and Al. The third layer particles is measured to be about 35-40% of raw fly ash. High volume fly ash cementitious composites containing second or third layer particles are tested under compression and bending, highlighting a higher strength and ductility in comparison to cementitious ones containing raw fly ash particles. KEYWORDS. Cementitious matrix; Raw fly ash; Second layer particles; Third layer particles.