Masonry Magazine October 1994 Page. 30
Recommended Practices (all weather)
The incremental procedures toward masonry construction include the following:
* Purchase of materials
* Materials receipt and storage
* Production of masonry mortar
* Scaffolding-access to working face
* Masonry construction
* Protection of completed masonry
Purchase of materials
During the purchase of materials, a manufacturer's Certification of Compliance should be received for all materials. The purchaser should be aware that some recommendations regarding all weather conditions may not result in a uniform aesthetic appearance for the completed structure.
The purchaser should be aware that some recommendations regarding all weather conditions may not result in a uniform aesthetic appearance for the completed structure. It is frequently recommended that the use of alternate Type III portland cement for the conventional Type I portland cement will provide some protection from cold weather effects. Such changes will affect the aesthetics of the completed structure, as color of mortar may be changed by cement composition.
sonry mortar ingredients and masonry units. These documents and their approved submittal reduce testing for compliance of mortar to the property specifications requirements of ASTM C 270°, when required to submit same. Additionally, the materials supplier/manufacturer should be consulted regarding the weather protection that will be provided from plant to project site. Shrink-wrapped units and weather resistive packages will ease on-site protection.
Materials receipt and storage
Materials delivered to the project site should be critically inspected for damage and non-conformance to applicable product specification before acceptance. Significant changes from previously accepted shipments, be it color, presence of cracks, chips, etc., should be recorded and an immediate decision should be made to accept or reject the delivery.
Materials storage should be attentive toward maintaining the products in the "as-recd" condition or upgrading the quality if deemed essential. Materials accepted below product standards can be upgrade or culled, but both require additional handling. Materials should be stored so the cementitious materials and units are high and dry to prevent water entry from melting snow or ice, rain or ground water. The storage area should not be adjacent a traffic throughway where water or soil could affect the material. Sand should be discharged on a mud slab or some other protective device to avoid native materials being introduced into the mixture.
Production of masonry mortar
Masonry mortar production remains essentially similar, regardless of climatic conditions. Temperatures effects are most significant. The temperature of the materials and the machinery for the production of the masonry mortar should be noted with some corrective action if the temperatures become excessive-hot or cold. The primary objective is the production of uniform batches with close control of the quantities of individual materials charged into the mixer. On-site production of the masonry mortar may be accomplished using batch mixers or dry blend mixers.
Batch mixing by shovelsful can be successful. Full bag measures of cement and full or partial bag measures of hydrated lime should be used with mixer capacity selected based on using these measures. To calibrate "shovelsful," a cubic foot measure should be used to establish the number of shovelsful of sand to produce the desired batch volume. Water additions should be by water meter or volume. The volume of mortar in the mixer should be noted and thereafter subsequent batches should be of equal volume. The mortar volume of each batch, thus, becomes a quality control measure.
Dry blend mixers accept the quality control exercised by the supplier of the preblended cementitious materials and mason's sand. Dry sand is combined with cementitious material. The dry blend mixtures may be contained in a silo or bag container. The dry blend is either discharged into a conventional batch mixer or into the throat of an auger mixer.
COLD WEATHER CONSTRUCTION PROCEDURES
* Code Requirements:
* Apply when ambient temperature is below 40 F
* 40 F to 25 F Heat mortar to 40 F to 120 F
Maintain mortar above freezing
* 25 F to 20 F Heat mortar to 40 F to 120 F
Heat both faces of masonry
Install windbreaks when wind velocity is greater than 15 mph
* Cold weather temperatures included in project specification.
* Master plan for cold weather masonry construction:
* No masonry construction
* Construct interior wythe during cold weather; await warm weather for construction of exterior wythe.
* Enclose structure and provide heat.
* Mortar production in weather protected enclosure.
* Provisions made for heating sand, water, and mixer.
* Provisions made for maintaining mortar warm on mortar board.
* Provisions made for enclosures to serve as windbreaks and allow heating masonry.
* Other