m 885 m »& m • i mm UNIVERSITY^ PENNSYLVANIA LIBRARIES COMPOSITE REPAIR OF SANDSTONE James Weldon Dossett A THESIS in Historic Preservation Presented to the Faculties of the University of Pennsylvania in Partial Fulfillment of the Requirements forthe Degree of MASTER OF SCIENCE 1998 H^ /isor Reader i. Matero Dr. A. Elena Charola AssociateProfessorofArchitecture LecturerinHistoricPreservation K sAjl^' Graduate Group Chair >G. Matero AssociateProfessorofArchitecture h^t Ms/ A/A |oz/m?/l>72*y UNIVERSITY OF PENNSYLVANIA " LIBRARIES 1 TABLE OF CONTENTS CONTENTS » LIST OF FIGURES v CHAPTER ONE: INTRODUCTION TO COMPOSITE REPAIR OF SANDSTONE 1 USE OF SANDSTONE AS A BUILDING MATERIAL 1 SANDSTONE DECAY 1 Sandstone Composition 2 Environment 3 Use 6 SANDSTONE TREATMENTS 7 Cleaning 8 Consolidation 10 Repairof Sandstone 1 COMPOSITE REPAIR 12 Color and Texture 13 WaterVaporTransmission and WaterAbsorption 14 Bond Strength 15 Strength 15 Dimensional Stability 16 16 Durability Composition 16 Sample Formulae forComposite Repair 20 CHAPTER TWO: TESTING PROGRAM 23 MATERIALS 23 Binder 23 Sand 26 Acrylic Admixture 28 Jahn M 70 #2 30 Stone. 31 COMPOSITE REPAIR FORMULAE 32 METHODOLOGY OF TESTING 34 Consistency 35 ii Composite Repairof Sandstone Table ofContents Time of Setting 39 Shrinkage During Curing 41 Thermal Expansion 44 WaterVaporTransmission 45 WaterAbsorption byTotal Immersion 48 Flexural Strength and Modulus of Elasticity 50 Bond Strength 52 Frost Resistance 56 Salt Crystallization 58 Accelerated Weathering 59 Abrasion Resistance 61 CHAPTER THREE: RESULTS AND CONCLUSIONS 63 CONSISTENCY 63 TIME OF SETTING 65 SHRINKAGE DURING CURE AND THERMAL EXPANSION 67 WATER VAPOR TRANSMISSION AND WATER ABSORPTION 68 FLEXURAL STRENGTH AND MODULUS OF ELASTICITY 71 BOND STRENGTH 74 FROST RESISTANCE 76 SALT CRYSTALLIZATION 79 ACCELERATED WEATHERING 81 ABRASION RESISTANCE 82 SUMMARY CONCLUSIONS 84 Lime Putty Based Formulations 86 Riverton Hydrated Hydraulic Lime Based Formulations 87 Hybrid Formulations - Portland Cement and Lime Putty 88 Jahn M 70 90 REFERENCES 92 APPENDIX A: TEST RESULTS 99 CONSISTENCY 100 TIME OF SETTING 101 WATER VAPOR TRANSMISSION 102 WATER ABSORPTION 105