Evaluation of the Behaviour of Lime and Cement Based Mortars Exposed at Elevated Temperatures

== Abstract ==

Exposure to fire and elevated temperatures is diachronically a significant decay 
factor, influencing the stability of structures. Cement and lime-based mortars have a different 
behavior when exposed at elevated temperatures, usually testified by the post-fire preservation 
state  of  historic  and  contemporary  constructions.  In  this  paper,  the  correlation  of  their 
properties  is  envisaged,  in  order  to  identify  the  key  elements  of  their  performance.  To  this 
direction, five compositions of cement and lime based mortars were manufactured and tested, 
after their exposure at 200oC, 400oC, 600oC, 800oC and 1000oC. The binders used concerned 
CEM  I42.5Ν  (C),  hydrated  lime  (L)  and  natural  pozzolan  (P),  while  the  systems  applied 
regarded C, C:L (1:1), L, L:P (1:1) and L:P:C (1:0.8:0.2) (parts per weight). The aggregates 
used were natural of siliceous origin and their gradation varied from 0-4mm to 0-8mm. The 
B/A ratio was 1/2 by weight and the W/B ratio was adjusted in order to maintain workability 
around 15±1cm. The  physico-mechanical  properties  of  the  specimens,  were  recorded  before 
and after their exposure at the selected temperatures. From the evaluation of the results, it was 
concluded that the mortars’ behavior was different at the early temperature rate (up to 600oC) 
according to their type, whereas the results were more comparable at the extreme temperature 
level.  Generally  it  was  observed  that  although  the  initial  strength  of  the  lime-based  mortars 
was  low  (1-4MPa),  they  presented  a  more  stable  and  efficient  performance  at  the  elevated 
temperatures, rendering them probably more resistant at the first stages of fire actions. Cement-
based  mortars  seemed  to  present  a  better  performance  at  the  highest  temperatures  of  800oC
and 1000oC.

== Full document ==
<pdf>Media:Draft_Content_655909731p645.pdf</pdf>
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