Research Series Report No. 112 The Pennsylvania Housing Research Center Sustainability of Residential Concrete Report prepared by: Pragati Singh Dr Andrew Scanlon December 2013 Pennsylvania Housing Research Center Penn State University 219 Sackett Building University Park, PA 16802 Telephone: (814) 865-2341 Facsimile: (814) 863-7304 E-mail: [email protected] Web Site: www.phrc.psu.edu Penn State is an equal opportunity, affirmative action employer, and is committed to providing employment opportunities to minorities, women, veterans, individuals with disabilities, and other protected groups. Nondiscrimination: http://guru.psu.edu/policies/AD85.html The Pennsylvania Housing Research Center (PHRC) exists to be of service to the housing community, especially in Pennsylvania. The PHRC conducts technical projects—research, development, demonstration, and technology transfer—with the support of numerous agencies, associations, companies and individuals. Neither the PHRC, nor any of its supporters, makes any warranty, expressed or implied, as to the accuracy or validity of the information contained in this report. Similarly, neither the PHRC, nor its supports, assumes any liability for the use of the information and procedures provided in this report. Opinions, when expressed, are those of the authors and do not necessarily reflect the views of either the PHRC or any one of its supports. It would be appreciated, however, if any errors, of fact or interpretation or otherwise, could be promptly brought to our attention. PHRC | 219 Sackett Building | University Park, PA 16802 i Sustainability of Residential Concrete Summary: Concrete is an established construction material known for its strength, durability and versatility. Its application in buildings consists of construction of foundations, structural frames, interior & exterior walls and slabs. In addition to its excellent structural properties, Concrete's environmental friendly features make it one of the most preferred construction material. Concrete is a green material in all stages of its life span. It can be made from by-products of manufacturing and power plants and it can be crushed and recycled as an aggregate for further use after its service life. The advantages of concrete buildings are numerous. Concrete has inherent property of thermal mass, energy efficiency and resistance to natural disasters. Concrete buildings have better air quality and reduced maintenance and energy costs. The sustainable concrete structures can lead to sustainable future for generations. This report highlights the important properties of concrete that make it a sustainable material. The report also discusses few latest technologies like insulated concrete forms and pervious concrete that further improve the sustainability of concrete. i Contents 1. Introduction ................................................................................................................................. 1 1.1 Objective ............................................................................................................................... 1 1.2 Advantages of concrete homes ............................................................................................. 1 2. Carbon Footprint ........................................................................................................................ 4 2.1 Cement production ................................................................................................................ 4 2.2 Operational contribution ....................................................................................................... 5 2.3 Reduction of residential carbon footprint ............................................................................. 6 3. Thermal Mass............................................................................................................................. 7 3.1 Using thermal mass in design ............................................................................................... 7 3.2 Energy efficiency due to thermal mass ................................................................................. 7 3.3 Drawbacks............................................................................................................................. 8 3.4 Summary ............................................................................................................................... 9 4. Thermal Transmission ............................................................................................................. 10 4.1 Insulation and thermal resistance ........................................................................................ 13 4.2 Design against thermal bridging ......................................................................................... 15 5. Service Life of Concrete (Concrete Durability)........................................................................ 16 5.1 Moisture .............................................................................................................................. 16 5.2 Freeze-thaw cycles .............................................................................................................. 17 5.3 Exposure to chemicals (alkali, sulfate, de-icing salts) ........................................................ 17 5.4 Corrosion of reinforcing bars .............................................................................................. 18 5.5 Abrasion .............................................................................................................................. 18 6. Concrete Structures: Resistance to natural disasters ................................................................. 19 6.1 Hurricane and high wind resistance .................................................................................... 19 6.2 Improving resistance against hurricane damage ................................................................. 20 6.3 Fire resistance ..................................................................................................................... 21 6.4 Flood resistance .................................................................................................................. 23 7. Pervious Concrete ..................................................................................................................... 24 7.1 Necessity of pervious concrete ........................................................................................... 24 7.2 Usage................................................................................................................................... 24 7.3 Properties ............................................................................................................................ 25 7.3.1 Compressive strength ................................................................................................... 25 7.3.2 Water-cement ratio....................................................................................................... 25 7.3.3 Cemetitious material .................................................................................................... 26 ii 7.3.4 Porosity and pore structure .......................................................................................... 26 7.3.5 Resistance to environmental factors ............................................................................ 27 7.4 Mix design .......................................................................................................................... 27 7.4.1 Use of recycled concrete aggregate ............................................................................. 28 7.5 Construction ........................................................................................................................ 29 7.6 Clogging .............................................................................................................................. 30 7.7 Benefits ............................................................................................................................... 30 7.7.1 Environmental benefits ................................................................................................ 30 7.7.2 Using pervious concrete to achieve LEED Points ....................................................... 31 7.7.3 Economic benefits ........................................................................................................ 31 7.7.4 Acoustic adsorption ..................................................................................................... 31 7.7.5 Water purification ........................................................................................................ 32 8. Insulated Concrete Forms ......................................................................................................... 33 8.1 Configuration ...................................................................................................................... 33 8.2 Advantages .......................................................................................................................... 34 8.3 Energy efficiency ................................................................................................................ 34 8.4 Comparative study .............................................................................................................. 36 8.5 Life cycle assessment .........................................................................................................