Grantee Research Project Results

2011 Progress Report: Alkali-Activated Cement (AAC) as a Sustainable Building Material

EPA Grant Number: SU834759
Title: Alkali-Activated Cement (AAC) as a Sustainable Building Material
Investigators: Barsoum, Michel , Moseson, Alexander J. , Crook, Abraham
Current Investigators: Barsoum, Michel , Moseson, Alexander J. , Crook, Abraham , Spencer, CJ
Institution: Drexel University
EPA Project Officer: Page, Angela
Phase: II
Project Period: August 15, 2010 through August 14, 2012 (Extended to August 14, 2013)
Project Period Covered by this Report: August 15, 2010 through August 14,2011
Project Amount: $75,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet - Phase 2 (2010) Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Awards , P3 Challenge Area - Sustainable and Healthy Communities , P3 Challenge Area - Chemical Safety , Sustainable and Healthy Communities

Objective:

Our research pursues the advancement and application of AACs through three specific aims respectively focused on basic science, commercial viability, and application in the developing world. Through the collaboration of three universities, experiential education at the pre-college, undergraduate, and graduate level is central to our approach. To actualize the potential benefits of AACs to people, prosperity, and the planet, we pursue three specific aims:

Aim 1: Research: Determine the relationships between chemical, microstructural, and performance properties of AACs

This is accomplished using various analytical techniques including microscopy, spectroscopy, mechanical testing, and statistical design of experiment. This aim is central to solving the challenges facing AACs.

Aim 2: Development: Investigate performance using key ASTM tests

Examples of such tests include time of set, strength, autogenous and drying shrinkage, freeze-thaw resistance, and three-point concrete beam bending. This aim is central to understanding the practical benefits and barriers to applications of AACs.

Aim 3: Application: Develop low-cost AACs for use in developing countries

AACs have been developed in response to the unique challenges and opportunities of Mumbai, India, as a high-quality yet affordable building material for to benefit slum dwellers.

Progress Summary:

Aim 1: Determine the relationships between chemical, microstructural, and performance properties of AACs

One refereed journal publication has been accepted for publication inCement and Concrete Composites. Another has been through several rounds of review. Through these publications, we presented evidence that: i) granular limestone is an active component in the alkali-activated system studied and, ii) formulae with up to 68% limestone content and no OPC are competitive in performance with OPC, while reducing CO₂and energy by up to 97%. Further study on the role of limestone has not been pursued, due in part to a Masters student scheduled to do it leaving the university.

Aim 2: Investigate performance using key ASTM tests

Progress has been made towards passing the requirements of ASTM C1157, in part through the systematic testing of scores of formulations. It remains, however, to find a reliable way to simultaneously pass the requirements both for initial set-time and 1-day strength.

Meetings were held with several existing and potential industry partners, to guide development toward commercialization. Some of the new contacts were made as a result of this project being the subject of a Drexel business plan competition team, which placed second in the competition. Business development was further made possible by the support of Ravi Malhotra, through the iCAST Triple Bottom-Line Impact Award. Difficulty in obtaining patents, due to copious prior art, remains the key obstacle to obtaining venture capital funding. A proposal to the Pankow Foundation passed the first round; a decision on funding will be made mid-December.

Aim 3: Develop low-cost AACs for use in developing countries

This was the most successful of the aims in this reporting period. One of the student leads, Alexander Moseson, was a Visiting Scholar for 6 months at the Indian Institute of Technology (IIT), Mumbai.Under the mentorship of Prof. D.N. Singh, and with the help of a recent graduate as a laboratory technician, Moseson developed a product line of AACs that meets the requirements of respective Indian Standards, using local materials, methods, and labor. A sidewalk was poured as a pilot test (Fig. 1), and certified third-party testing confirmed the majority of the results.

Figure 1: Pour of Pilot Sidewalk (Footpath)

On the campus of IIT Bombay. Pictured in foreground left to right, are Prof. D.N. Singh, the author, and a representative of a major cement producer

In addition to technical development, Moseson investigated the sociopolitical aspects of applying the material, especially with respect to empowering slum dwellers through its manufacture and use (in lieuof the originally planned review article on cementitious materials from around the world). This resulted in a paper submitted to a refereed journal, which details the context and practical options to implement the cement so that it benefits of higher quality and lower cost (up to 44%) are enjoyed by slum dwellers. The technical and socio-political results were summarized in a conference proceedings paper, and form the capstone of Moseson's recently defended Ph.D. thesis.

Further, the research team was retained by the Mennonite Central Committee (MCC) of Bangladesh to investigate two types of alternative cementitious material: Sorel Cement and soil-based geopolymers. Both theoretical and empirical investigation was conducted, and a comprehensive report delivered.

Future Activities:

A gate-to-gate life-cycle analysis was conducted as part of one of the journal articles currently in review. An optimized AAC formula achieved a competitive 28 day paste strength of 64 MPa, yet would produce ~ 25 kg CO₂/tonne and require ~ 50 kWHs/tonne, representing 97% reductions in both CO₂ and energy compared to OPC, and 93% reductions for a typical concrete mix. Material costs for optimized mixtures are ~$32 - $45/tonne, so it could be sold at a discount to OPC, primarily benefitting consumers, or sold at a premium for its ecologically benign characteristics, primarily benefitting producers. If used as a replacement for OPC in typical concrete it could save 40% on cost and 93% on CO₂ and energy. Similarly, in India, cost savings were as high as 44%, yielding a savings on concrete of 7% and on a typical slum improvement project of 3-5%. CO₂ and energy reduction was as high as 92%, providing further opportunity for economic benefit through carbon credit sales. In short, progress has been excellent on certain fronts, and challenging on others.

Journal Articles on this Report : 1 Displayed | Download in RIS Format

Publications Views

Other project views:	All 6 publications	1 publications in selected types	All 1 journal articles

Publications

Type	Citation	Project	Document Sources
Journal Article	Moseson AJ, Moseson DE, Barsoum MW. High volume limestone alkali-activated cement developed by design of experiment. Cement and Concrete Composites 2012;34(3):328-336.	SU834759 (2011)	Full-text: alexmoseson.net - Full Text PDF Exit Abstract: ScienceDirect - Abstract Exit

Supplemental Keywords:

uilt environment, materials and chemicals, green chemistry, environmentally benign substitute, waste to value, sustainable construction materials, green building, alternative construction material

Progress and Final Reports:

Original Abstract

2012

Final Report

P3 Phase I:

Alkali-Activated Slag Cements as a Sustainable Building Material  | Final Report