{"603875":{"#nid":"603875","#data":{"type":"event","title":"PhD Defense by La Sasha Walker","body":[{"value":"\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003ESchool of Civil and Environmental Engineering\u003C\/strong\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003EPh.D. Thesis Defense Announcement\u003C\/strong\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003ESustainable Solution to Recycled Concrete: Improving Structural Applications\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003E\u0026nbsp;\u003C\/strong\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003EBy\u003C\/strong\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003ELa Sasha Walker\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003EAdvisors:\u003C\/strong\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003EDr. Reginald DesRoches (COE - Rice University) \u0026amp; Dr. Kimberly Kurtis (CEE)\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003ECommittee Members:\u003C\/strong\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003EDr. Lawrence Kahn (CEE), Dr. Susan Burns (CEE), and\u0026nbsp; Dr. T. Russell Gentry (COA)\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003EDate \u0026amp; Time:\u003C\/strong\u003E Thursday, March 29, 2018 at 2 pm\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003ELocation:\u003C\/strong\u003E Sustainable Education Building, 122\u003C\/p\u003E\r\n\r\n\u003Cp\u003EConcrete debris is an underutilized resource often used as a non-structural fill material or even landfilled. For instance, in\u003C\/p\u003E\r\n\r\n\u003Cp\u003E2014, the United States landfilled approximately 375 million tons of concrete, some of which could have been utilized to offset\u003C\/p\u003E\r\n\r\n\u003Cp\u003Ethe 1 billion tons of stone aggregate produced that same year. To evaluate sustainable solutions to this issue, the present study\u003C\/p\u003E\r\n\r\n\u003Cp\u003Einvestigates various options to expand the use of recycled concrete in structural applications. Specifically, this study addresses\u003C\/p\u003E\r\n\r\n\u003Cp\u003Ethe knowledge gaps with using recycle concrete in structural concrete by focusing on two main aspects: (1) use of recycled\u003C\/p\u003E\r\n\r\n\u003Cp\u003Econcrete aggregate varying in the maximum size as a complete replacement of coarse aggregate, and (2) use of recycled\u003C\/p\u003E\r\n\r\n\u003Cp\u003Econcrete fines, particle size of 74\u0026mu;m or less, as partial replacement of cement at 15% and 20%.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe structural and durability behavior of mixes are evaluated using a variety of standard test methods including compressive\u003C\/p\u003E\r\n\r\n\u003Cp\u003Estrength, shear and flexure behavior, rapid chloride penetration test, surface resistivity, and accelerated mortar bar test.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EFurthermore, the potential increase in the reactivity of recycled concrete fines through ball-milling and calcining is investigated\u003C\/p\u003E\r\n\r\n\u003Cp\u003Eusing isothermal calorimetry, X-ray powder diffraction, thermogravimetric analysis, and particle size analysis. Results show\u003C\/p\u003E\r\n\r\n\u003Cp\u003Erecycled aggregate concrete provide adequate strength and durability comparable to natural aggregate concrete at 100%\u003C\/p\u003E\r\n\r\n\u003Cp\u003Ereplacement of coarse aggregate. Recycled aggregate concrete in comparison to natural aggregate concrete at the same MSA\u003C\/p\u003E\r\n\r\n\u003Cp\u003Ehad similar compressive strength (generally within +\/- 10%) of ordinary concrete, which exhibited strength of 6 ksi at 28 days,\u003C\/p\u003E\r\n\r\n\u003Cp\u003Eflexural strength of 780 psi at 28 days, and shear strength of 800 psi at 28 days, respectively. Both natural aggregate concrete\u003C\/p\u003E\r\n\r\n\u003Cp\u003Eand recycled aggregate concrete had high to moderate permeability levels at the water-to-cement ratio evaluated.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThermogravimetric analysis shows that recycled concrete fines do not exhibit pozzolanic reactivity and therefore act as filler in\u003C\/p\u003E\r\n\r\n\u003Cp\u003Ecement systems. Activation techniques did enhance the reactivity of recycled concrete fines, as assessed through examination\u003C\/p\u003E\r\n\r\n\u003Cp\u003Ecement hydration kinetics and these improvements were linked to increases in surface area, reductions in impurities, and\u003C\/p\u003E\r\n\r\n\u003Cp\u003Emodified chemical composition. Of the activation methods explored, calcining at 750\u0026deg;C produced the most reactive recycled\u003C\/p\u003E\r\n\r\n\u003Cp\u003Econcrete fines. This work demonstrates that recycled concrete can be used for structural applications to reduce the amount of\u003C\/p\u003E\r\n\r\n\u003Cp\u003Econcrete debris in landfills and the usage of natural resources.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":"","field_summary_sentence":[{"value":"Sustainable Solution to Recycled Concrete: Improving Structural Applications"}],"uid":"27707","created_gmt":"2018-03-16 13:17:27","changed_gmt":"2018-03-16 13:17:27","author":"Tatianna Richardson","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2018-03-29T15:00:00-04:00","event_time_end":"2018-03-29T17:00:00-04:00","event_time_end_last":"2018-03-29T17:00:00-04:00","gmt_time_start":"2018-03-29 19:00:00","gmt_time_end":"2018-03-29 21:00:00","gmt_time_end_last":"2018-03-29 21:00:00","rrule":null,"timezone":"America\/New_York"},"extras":[],"groups":[{"id":"221981","name":"Graduate Studies"}],"categories":[],"keywords":[{"id":"100811","name":"Phd Defense"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1788","name":"Other\/Miscellaneous"}],"invited_audience":[{"id":"78761","name":"Faculty\/Staff"},{"id":"78771","name":"Public"},{"id":"174045","name":"Graduate students"},{"id":"78751","name":"Undergraduate students"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}}}