quambi house - Great Lakes Council

2BatchingBatching will be undertaken using gauge boxes or similar receptacles which allow accurate reproduction of the batchvolumes. Materials measured in such receptacles shall be struck off level with the top.Under no circumstances shall materials be batched using shovels or any container which cannot be struck off level. Sandwill be of a moisture content which does not affect the ability for it to be volume batched.The nominal sand mix proportion may be varied in the range of 2½ to 5 parts to produce a mix of the required strengthand permeability to match the brick or stone. Final proportions will be approved by the Engineer following the making,curing and testing of trial mixes.As a guide to the final proportions, the air voids content of the sand should be determined and the binder proportionedsuch that the binder, in a plastic condition, has a volume slightly in excess of the air voids. This will ensure workabilityand strength of the mix. A test method for determining air voids is appended.The pozzolan shall be batched at a nominal proportion of 1 / 10 the lime volume. This proportion may be varied if directedby the Engineer to produce mixes of different cured strengths.MixingProcedureSuitable personal protective equipment as set out in the lime manufacturer’s MSDS shall be worn at all times whenhandling quick lime.The dry ingredients, with a total volume not exceeding the capacity of the mixing equipment, shall be placed in a mortarmill (preferable) or other approved mixer. If a mortar mill is not available, best results may be obtainable using handtools.Water shall be introduced gradually as the mix is turned over and mixing continued until a workable mix has beenobtained and steam ceases. If excessive steam evolves early in the mixing process, the amount of water used should beincreased immediately.Mill mixing or stirring and hoeing shall continue for at least 5 minutes after all reaction has ceased.Preparation for useIf the mortar has been mixed by hand it may need sieving to remove oversized particles. Such particles would normallybe broken down in a mortar mill unless they are contaminants (e.g. non-lime rock).The fresh mortar shall be placed in a suitable container or on a board and covered with plastic sheeting and/or wethessian and left for 24 hours: it shall then be “knocked up” before use. Additional water may be added during knockingup to produce the required workability.Alternative preparationIt has been found that the properties of the resulting mix can be enhanced significantly if the lime, sand and water aremixed and allowed to stand, protected from drying out, for a period of some weeks. The pozzolan is then added beforeuse.UseUnless otherwise directed and where the mix is to be used for repointing, repointing shall not be less than 25 mm deep.The masonry to be repointed shall be thoroughly soaked prior to repointing: this may require a number of applications ofwater over a number of days. Joints shall be repointed struck to the required shape. Excess mortar shall not be allowed tospread over the brick surface.The work shall be shaded if required and mist sprays may be used to prevent the work drying out.Completed sections of wall are to be covered in hessian bags which are to be kept wet continuously for a period of atleast seven (7) days following mortar application.©Bill Jordan & AssociatesVersion 6/10Hot Lime Mortar Specification