Talk:Lime mortar

message: The National Park Service U.S. Department of the Interior, 2 Preservation Briefs, Repointing Mortar Joints in Historic Masonry Buildings,Robert C. Mack, FAIA, and John P. Speweik,is a great guide to help answer questions about Lime Mortar.
Topics include....
»Historical Background
Identifying the Problem Before Repointing
»Finding an Appropriate Mortar Match
»Properties of Mortar
»Mortar Analysis
»Components of Mortar
»Mortar Type and Mix
»Budgeting and Scheduling
»Contractor Selection
»Execution of the Work
»Visually Examining the Mortar and the Masonry Units
»Summary
»Conclusion
»Selected Reading
--HLHiatt (talk) 20:46, 28 September 2010 (UTC)
thread_title:  2 Preservation Briefs 

message: Proportions given don't specify materials so they're useless, especially from an encyclopedic POV. Anyone able to clarify? --mikaultalk 01:37, 21 July 2009 (UTC)
thread_title:  Lime with Cement section 

message: First, the history is all wrong. Both in Europe and in North America, lime was not replaced by portland cement in the 19th Century, but by low-fired hydraulic cements produced from argillaceous (high clay) limestones. In Europe, it was called Roman Cement (no connection to the cement produced by the Romans) and in North America it was called Natural Cement. Natural and Roman cements were the dominant hydraulic binders on both continents throughout the 19th Century, with portland cement only achieving market dominance at the turn of the 20th Century.
Next, the inference that portland cements (or natural cements for that matter) are inappropriate for historic restoration is simply false. Tens of thousands of historic buildings (if we select pre-1900 as an arbitrary definition of "historic") were built with these hydraulic cements. Nowhere in the restoration mainstream has there been any credible argument made for restoring natural cement or portland cement buildings with lime. In-kind restoration is generally the agreed-upon default, provided original materials are available, performed well in the first place and are known to work as well in restoration as they did in original construction. (NOTE: An earlier comment on this page correctly references the failure of lime as a restoration material in salt-contaminated masonry. This would be justification for rejecting lime in such applications in favor of an alternative that works better, such as natural cement.)
Finally, references to combinations of lime and cement being unacceptable is highly controversial and not settled technical fact. While the Smeaton project concluded that mixtures of cement and lime lower than 1 part cement to 1 part lime may be prone to early failure, there are thousands of buildings built and/or repointed with ASTM C270 Type O mortar (the proportion specifications of which include 1:2:9 cement-lime-sand as a possible proportion) which have not failed prematurely. The RILEM historic mortars committee, currently developing a new standard, has concluded that portland cement or other hydraulic cements can be added to non-hydraulic limes at levels as low as 10% without negative results.
Edisoncoatings (talk) 03:47, 6 October 2009 (UTC)
thread_title:  Lots of Incorrect Information  

message: I do not want to edit the article directly since people might reference this to obtain a recipe but the information in the mix section might be misleading as it directly advises that in the 1:3 ratio, lime putty should be used. From what I have been reading (for example in http://www.buildingconservation.com/articles/mythmix/mythmix.htm ) this ratio should be for quicklime and also should be describing the addition of water. The water is added to the quicklime until a paste consistency is achieved, then the 3 parts sand are dumped on top and left for a while before the whole thing is turned and mixed completely.
If we use 1:3 quicklime:sand and added water as my information suggests, the discrepancy between the historical findings and the putty recipe is explained: "analysis of mortar samples from historic buildings typically indicates a higher ratio of around 1 part lime to 2 part aggregate/sand was commonly used" . The recipe on a 25kg sac of Holcim NHL5 lime I recently bought in France is as follows: 25kg quicklime powder (about 20 litres from bag measurements), 60 litres of sand, 11 litres of water. This would result in a mix of 20+11 : 60 which is approximately 1:2 which agrees with the historical findings.
Can somebody with actual experience please verify that all this actually makes sense?  —Preceding unsigned comment added by Aris637 (talk • contribs) 21:47, 21 July 2010 (UTC)
thread_title:  Mix section, quicklime not putty 

message: It is stated that hydrated lime (Ca(OH)2) eventually turns back to calcium carbonate (CaCO3) by combining with carbon dioxide (CO2) from the air, but this obviously does not add up.  The end products of the cycle are calcium carbonate AND water (H2O).  This is correctly stated in other sources, but I have not seen any explanation of what happens to the water released.  As lime mortar is porous, presumably the water migrates to the surface and evaporates.  Or does some of it remain permanently in the mortar, retained by capillary attraction?  Can someone who knows the score add something?109.146.48.57 (talk) 18:21, 12 May 2015 (UTC)
replies: text: I'm not sure of the chemistry details in this case, but I suspect the water becomes a hydrate, a dry solid. You may know that copper sulphate is a solid dry blue crystal, but it also contains water, and if you heat it to the point where the 'hidden' water leaves it, it becomes anhydrous, a dry white powder. To be a solid cement seems to imply that water is retained in a dry crystal.31.51.85.128 (talk) 18:51, 12 May 2016 (UTC)
replies: text: Someone tidy-minded can clean this current comment up after it's entertainment value expires. I just wanted to note the occasion, apparently I answered just now, a question that is exactly a year and a half-hour older than my reply! Apparently my TARDIS is on the blink, again...31.51.85.128 (talk) 18:56, 12 May 2016 (UTC)
thread_title:  Completing the cycle 

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thread_title:  External links modified