Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Lightweight Concrete Mixture
Name: Hector E.
Status: Educator
Age: 50s
Location: N/A
Country: N/A
Date: September 2003


Question:
Could I mix concrete with polystyrene beads and bentonite and get a homogeneous mixed compound that is lightweight?



Replies:
It is possible to make very lightweight concrete with polystyrene beads, but I am not familiar with any mixes that use bentonite for that purpose. (That does not mean it will not work, necessarily, I have just never heard of it.) Normal concrete uses stone, sand, Portland cement, and water. For simple lightweight concrete, I would suggest a combination of polystyrene beads, vermiculite, Portland cement, and water. As a civil engineering college student, I participated in the making of several winning, though fragile, concrete canoes out of this type of mixture back in the 1980's.

Most people think that concrete has to "dry" to get hard, when, in fact, it actually must be kept moist for at least 3 and preferably 7 to 10 days to allow the cement in the concrete to chemically react and harden. (This is known as curing.) So, you should keep your lightweight concrete moist initially to ensure that it reaches its potential for strength. No moisture equals no hardening.

Concrete canoes have become vastly more sophisticated since I was a student 15+ years ago. The University of Wisconsin at Madison has a very good web page detailing their defending 2003 national championship canoe at www.cae.wisc.edu/~canoe/ . As a South Carolinian, I am proud that Clemson University (www.ces.clemson.edu/~canoe/) has been the most successful concrete canoe competitor in recent years. (But, as a University of South Carolina graduate, I'd also like to point out that we used to whip them consistently back in my day...:-)

Andy Johnson



Click here to return to the Engineering Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory