Lab Note #4
Mar 20, 2014

Good Evening Backers,

Thanks again for helping us make some great strides. We are 2 steps closer to saving the world with all the concrete in it.

And its all because of your support.

We currently have ALL our materials and we hit the ground running.

Attached to this lab note are first 24 hours of hydration for the two Geopolymer grouts that we have designed.

That's right I said grout and not concrete. Our first round of testing we are identifying a process to use different waste materials (specifically coal combustion residue,CCR). We have 10 samples of CCR - 5 were about to landfilled when they were collected and 5 are the creme' de la creme' of CCR.

The two mixes we conducted used the following materials:

GEO46 - Mid/High Grade Slag, High Grade Class F Fly Ash, Hydrated Lime, Binder/Water ratio - 0.45

GEO47 - Mid/High Grade Slag, Extremely Low Grade Class C Ash, Binder/Water (b/w) ratio - 0.45

The fresh properties were:

GEO46 - 2 cm slump, sticky mess - reduce lime content and increase Class F Fly Ash

GEO47 - 12 cm slump, fluid, close to segregation - reduce b/w and HRWR

After 24 hours the samples were set up. Below you'll see some semi-adiabatic temperature curves of these mixes.

As you can see, the geopolymer grouts have a much lower temperature of hydration than an ordinary Portland Cement (OPC). OPCs make up the hydrated cement matrix of concrete - the grey stuff.

The geopolymers have a dramatically different series of events when compared to the smooth and predictable transition of the OPC. GEO47, which has the nastiest and dirtiest CCR had an excessively large peak temperature within 5 hours and then died off, with a small climb towards the end of 24 hours. GEO46, the creme' de al creme', had more of a gradual curve. Our process will have to be able to switch between the two grades so that we will be able to make these disaster relief homes no matter the material quality.

At 14 days we'll be crushing the samples and I'll be posting the strengths. In between then I'll also be posting the remaining 3 days on the temperature curves.

The 2 mixes will be iterations where we will be refining the water, binders and chemicals to reach a 28 day compressive strength of 5000 psi (+/-500 psi) while maintaining a semi-fluid slump.

We are having an awesome time with this project.

If you have any questions don't hesitate to ask.



Please wait...