South Carolina Brick Masonry - Green Forever Insights in Preservation and Restoration South Carolina Preservation Month Workshop, May 14, 2010
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South Carolina Brick Masonry - Green Forever Insights in Preservation and Restoration South Carolina Preservation Month Workshop, May 14, 2010 Drayton Hall 1780 Denis A. Brosnan, PhD, PE Institute for Innovation in Building Materials And The National Brick Research Center Clemson University Today’s Five Part Presentation 1. Something Old – Something New in “Sustainability”. 2. First Brick Made at Mount Pleasant Since 1860. Grad students from USC make bricks in 2010. 3. Bricks. 4. Mortar. 5. Case Studies. PART 1 Something New Environmental Movement: From the Environment is a “Sink” To Conservation Protection Sustainability Sustainability “All humans should be able to enjoy a decent level of well being taking from nature sustenance without interfering with the continuity of nature and without harm to other life forms on the planet.” AIA’s Environmental Resource Guide (1996) Founder in 2001 of Johnston Design Group, Scott Johnston leads an architectural firm that is dedicated to environmentally sustainable design. The firm has been recognized nationally with numerous awards and publications for excellence in sustainable design. The practice offers sustainable design consulting and the authoring of green design guides, conservation development planning, historic preservation and adaptive reuse consulting, and architectural services for a variety of education, mixed use, affordable housing, and custom residential projects. Scott Johnston AIA, Greenville, SC ASTM Sustainability Standards: E 2432-05, “Standard Guide for General Principles of Sustainability Relative to Buildings”. E 2129-05, “Standard Practice for Data Collection for Sustainability Assessment of Building Products”. E 917- 05, “Standard Practice for Measuring Life-Cycle Costs of Buildings and Building Systems”. Do these standards accurately reflect the longevity of masonry materials? Guide for environmental performance claims. Example of an Industry Association Publication Brickwork is durable and . Brick building can be and are reused. However, Tech Note 15 seems to discourage use of salvaged bricks. People in 1886 took bricks from the ruins for construction of their buildings. All About Clay Bricks Prof. James Campbell’s Book Has Been Available for About Five Years The Egyptians were smart! They knew how Something VERY Old to fire pottery to meet specific purposes. The world’s oldest mud bricks were discovered in Jericho near the Dead Sea (about 8300 to 7600 BC) with dimensions of 260 X 100 X 100 mm. Later bricks from the same site were longer and flatter (400 X 150 X 100 mm). The picture above shows an image from the Tomb of Rekh-mi-Re (1450 BC). The Egyptian bricks contained straw to strengthen the bricks and to reduce drying shrinkage from the alluvial clays. These were possibly the world’s FIRST composite materials. First Fired Bricks – Mesopotamia The earliest fired bricks were found in Mesopotamia (Iran) made about 5000 BC and used to form a drain. Pottery was developed about 7000 – 6000 BC. Thus, water resistance (“durability”) was a first reason to make fired bricks, as the area had frequent floods. Nevertheless, records from 2003 BC indicate fired bricks were 30 times more expensive than mud bricks. According to Campbell, “It took a civilization of much greater sophistication to … afford fired bricks”. James Campbell in Brick, A World History (2003) Ziggurat Choga Zanbil (1250 BC) Palace Throne Room, 604 – 652 BC Brickmaking was greatly improved by the Babylonians, who developed glazed bricks. Fired bricks in Babylon remained expensive at about five time the cost of mud bricks. The Romans Roman Tomb, 150 AD (Inset – Roman Brick Shapes), Notice the color of the bricks as “salmon”. This led to the tradition of coating bricks with stucco in Southern Europe. Britain! Is this a brick masonry building? Bricks Imported to the Colonies “The body of the church is built of brick imported from England”, www.stjamesec.org/brickchurch.html. THIS IS UNLIKELY! A large ship could carry about 6000 bricks. While bricks were imported into New York, particularly from Holland (yellow and black bricks), most claims of imported bricks seem to be claims of a status symbol coveted in the 1700’s. See Houses Near McClellanville, SC of Bricks Imported from England (1904). Fire Resistance Becomes a Great Motivator: London (1666), Charleston (1861), Chicago (1871), Clemson (1894), San Francisco (1906), etc. Beginnings in Charleston Loading Levy at Lexington Plantation Something Old/Something New • To understand “Greenness” of brick masonry, you first consider the proven durability of fired bricks. Buildings 2000-3000 years old are still standing. • Early motivation to use fired clay bricks included durability – water resistance and fire resistance. • The Romans perfected brickmaking – establishing methods to make durable brick for Northern Europe by firing them “harder”. • A thriving brick industry developed in South Carolina in the 1700’s along the coast. Questions on Part I? Part 2 USC Grad Students Make Bricks on Lexington Plantation One goal of this project was to illustrate methods to make restoration bricks for Fort Sumter National Monument. Students - Sarah Swinney and Lee Durbetaki. Tempering the Clay Sarah and Lee were doing a special project For Dr. Bob Weyeneth, Professor of History, Director – Public History Program, University Lee Ready to “Throw” a Brick of South Carolina. Skove Kiln, Photo in the Charleston Museum Skove Kiln, Colonial Williamsburg Sarah and Lee’s Bricks in a Kiln at Clemson Wall at Fort Sumter USC Student’s Bricks Questions on Part 2? Part 3 Some Key Properties of Bricks Property Originates From Consequence Strength Partial vitrification in firing. Load bearing capacity. Indicated by “ring” or “thud”. Absorption Porosity in the fired brick. Assists in mortar adhesion, but excessive absorption leads to durability concerns. Color Mineral constitution of the Red bricks contain hematite brick (chemical analysis). (Fe2O3), black bricks contain magnetite (Fe3O4), and yellow bricks (lime). White bricks contain little iron oxide. Soluble salts Soluble constituents in the Discoloration called fired brick (or mortar). efflorescence. Durability Too many “fine pores” in Freezing of water or salt the brick (Those generally saturated brick causes “spalling” less than about 5 microns). in the wall. Comparing Modern and Old Brick Properties Property Bricks Made Before Modern Molded ~1900 Bricks Compressive Commons: 5293 Average Strength (CS), psi 2000-4000 ( =1822 psi) Facing Bricks: 4500-6800 ASTM C216 SW 3000 Average Specification on CS (2500 for any individual unit) Cold Water Commons: 7 – 16 < 14 (implied); Absorption (CWA), Facing: 7 - 15 Have different % specs for SW and MW bricks. Boiling Water Commons: 9-23 < 17 (average) and Absorption (BWA), Facing: 11-19 < 20 (for any % individual unit) CWA/BWA Commons: 0.67-0.93 < 0.78 Average (C/B or S) Facing 0.66-0.91 < 0.80 (for any individual unit) Durability concerns for old brick usually involve high absorptions and high CWA/BWA. SAMPLE Lexington Fort Fort Fort Fort Plantation #1 #2 #13 #31 Brick are fired to develop a glass (Modern) phase that serves to bond Family 1250oC firing 2 1 3 4 particles together permanently. temp. This phase is primarily XRF responsible for the durability of Al2O3 12.27 10.56 7.01 7.71 7.25 bricks. SiO2 78.32 80.41 78.74 77.23 82.44 Fe2O3 5.53 4.00 3.49 6.07 4.14 TiO2 1.23 1.33 1.01 1.41 1.24 Bricks are first characterized by MgO 0.42 0.57 7.44 0.49 0.86 CaO 0.60 0.59 0.59 0.74 0.97 their absorption properties (cold Na2O <0.5 <0.5 <0.5 <0.5 <0.5 water absorption or CWA and K2O 1.17 1.34 0.57 1.55 1.29 LOI 0.30 0.47 0.48 boiling water absorption or BWA). Other XRD Q,T,C,S Q,T,C,A3S2 Q,T,C,A3S2 Q,T,C,A3S2 NA The ratio CWA/BWA or C/B Physical Properties CWA 8.47 15.26 18.64 13.86 19.59 reflects the pore structure of BWA 17.81 21.05 23.43 23.54 24.95 the brick and is related to C/B 0.57 0.72 0.80 0.59 0.79 freezing and thawing Crushing Strength 4386 3556 NA NA NA durability. Porosity and Density BD 2.02 1.62 1.57 1.61 1.52 Most people are very concerned AP 29.04 34.18 36.76 35.93 38.01 with compressive strength. It Fraction >10 , % 58.52 Fraction, 1-10 , % 37.11 requires further consideration. Fraction <10 , % 4.37 8.4 1.9 4.4 9.4 Compressive Strength is measured by loading the brick to failure (left). The compressive strength is the load at failure divided by the area of the loaded face. In the process, the brick tends to slightly become “pancake shaped” resulting in tensile cracking. Most old hand-made bricks have a compressive strength of 2000 – 3000 psi (lb/in2). The reason for the range in properties is the uneven heat distribution in skove kilns. It was the usual practice to sort bricks by color and/or “ring” with light colored bricks called “commons” – for use in interior locations. The bricks that had experienced higher temperatures were classified as facing bricks and always used on the exterior. The average load on individual bricks in a wall is less than 25 psi (1.25% of strength). There is no exact relationship between durability and compressive strength! Usually the durability is best estimated using the water absorption characteristics. Other Brick Considerations in Restoration: Modulus of Elasticity – the ratio of stress to strain or an index of “stiffness”; Restoration bricks should not be stiffer than the majority of bricks on the structure. The method of forming and the degree of firing affect stiffness. Water Vapor Permeability – the rate of vapor transmission is usually high in old bricks due to their high porosity.