Grantee Research Project Results
2019 Progress Report: Recycled Glass: Cement/Fly Ash Substitute in CLSM
EPA Grant Number: SU839469Title: Recycled Glass: Cement/Fly Ash Substitute in CLSM
Investigators: Solanki, Pranshoo , Jin, Guang , Bierma, Tom
Institution: Illinois State University
EPA Project Officer: Callan, Richard
Phase: I
Project Period: December 1, 2018 through November 30, 2019 (Extended to June 1, 2020)
Project Period Covered by this Report: December 1, 2018 through November 30,2019
Project Amount: $15,000
RFA: P3 Awards: A National Student Design Competition Focusing on People, Prosperity and the Planet (2018) RFA Text | Recipients Lists
Research Category: P3 Challenge Area - Air Quality , P3 Awards
Objective:
The primary objective of this project is to reduce air pollution by significantly increasing the use of recycled glass as a substitute for Portland cement and fly ash in concrete projects. Use of recycled glass currently faces a number of barriers. This project investigates the use of recycled glass in a unique construction material (controlled low-strength material, CLSM) that has the potential to overcome these barriers and accelerate broader adoption of recycled glass as a cement/fly ash substitute. The specific objectives of Phase I are to determine the relationships between three input material (recycled glass) parameters and four product (CLSM) performance measures. These relationships will allow CLSM users and producers to specify mixes that will reliably meet construction project objectives. The use of recycled glass as a cement/fly ash substitute would not only prevent air pollution from Portland cement production, it would also benefit local recycling programs and help limit costs for concrete products. It is expected to be particularly helpful in rural areas where transportation costs create high prices for cement and fly ash as well as poor local markets for recycled glass.
Progress Summary:
- An attempt was made to clean and crush single-stream waste glass which indicated that desired gradation can be achieved.
- A total of 20 mixtures of CLSM were prepared by using different proportions of finer and coarser portion of glass powder as a fly ash substitute in CLSM. Each mixture was tested for flowability and cylindrical specimens were prepared by using split molds fabricated in the laboratory.
- Further, this research examined the effect of mix proportions namely, water to cementitious (w/c) ratio and glass content, on the flowability and compressive strength of CLSM mixtures.
Conclusions: Based on the results following conclusions could be drawn:
- Single-stream waste glass could be cleaned and crushed to obtain desired gradation. However, crushing single-stream waste glass is labor intensive and milling equipment is recommended for crushing.
- Based on flow consistency results, waste glass powder has the potential to be a suitable replacement of cementitious material in CLSM. However, consistency flow were found to be dependent on time of mixing and amount of water. Therefore, proper mixing and control of water in CLSM containing waste glass is recommended.
- Compressive strength was found to improve with increase in finer portion of the glass powder, i.e., ACAS glass percentage. The finer ACAS glass percentage of 50% or more is recommended to achieve strength greater than control specimens. Substitution of fly ash with 100% finer ACAS glass produced maximum strength of CLSM specimens. However, additional study is needed to find the optimum percentage and size of waste glass which can be used to achieve strength level recommended by specifications.
- Flowability of mixes was found dependent on w/c ratio and in general, flow of mixes increases with increase in w/c ratio. Finer glass content improved flowability, however, coarser glass was found to decrease flowability.
- Lower w/c ratio produced higher compressive strength. However, mixes containing high volumes of coarser glass was found more strength-sensitive towards change in w/c ratio.
- The density of CLSM specimens correlated well with the moisture content. Lower moisture content produced denser CLSM structure.
Future Activities:
- Study samples under Scanning Electron Microscope (SEM) -- Selected CLSM, glass, cement, fly ash and sand samples will be observed using analytical techniques, namely, SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive Spectroscopy) located in the Materials Research Laboratory (MRL) of UIUC. A JEOL JSM 6060LV Low Vacuum Scanning Electron Microscope available in the MRL of UIUC will be used to visually observe the coated specimens in accordance with ASTM C 1723. The JEOL JSM 6060LV is fitted with energy dispersive X-ray spectrometer (EDS). The EDS will be used for elemental analysis and digital X-ray mapping of the specimen. We believe that the micrographs and elemental analysis maps obtained from SEM/EDS will assist us in rationalizing macro-behavior, i.e., UCS of CLSM.
- Engage rural community -- The mayor of Durango has expressed interest in the proposed research and exploring ways in which Durango could benefit, based on the research results (see attached letter of support). A local ready-mix plant (Four Corners Materials) and civil engineering firm (Russell Planning & Engineering) have also expressed potential interest and willingness to participate. These and other partners in the community will be interviewed to explore potential benefits and barriers for glass-based CLSM and determine the best next-steps for introducing glass-based CLSM in Durango, surrounding communities, and nearby tribal areas.
Journal Articles:
No journal articles submitted with this report: View all 2 publications for this projectSupplemental Keywords:
pozzolan, flowable fill, glass powderRelevant Websites:
'Better and greener:' ISU project focuses on recycling, sustainability Exit
ISU Student Team Receives EPA Grant For Sustainable Construction Project Exit
EPA awards $15,000 for student project on sustainable construction Exit
Student project on sustainable construction wins EPA grant Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.