There is a sad “game” called Russian roulette. Russian Roulette is a game of chance with the potential for disastrous results.
Cement mixing with shovels on the ground is like placing one bullet in the cylinder, spinning and then pulling the trigger. Shovels in Haiti replace the bullets, because when shovels do the mixing, the odds of disaster go up during an earthquake.
We would never want people to live in a structure that was mixed with this type of random result. Yet in Haiti we see a Roulette-style gamble happening at thousands of construction sites around the country. Instead of a gun with a bullet, it is buckets that could contain a deadly mixture. Buckets filled with concrete of random consistency. A concrete that might have 2800 psi strength in one bucket and then 800 in the next.
Engineers have tested the concrete block and the foundation mixes that come from this practice and they suggest that the odds of another disaster is high.
The poor use shovels on the ground to mix concrete. They shovel-in some aggregates and some cement with water and then they turn it over and over to create several bucket loads of wet mix. The buckets scoop-up this mixture and move it up a ladder to pour a roof above their heads. Bucket by Bucket they fill the columns that hold up several floors of these concrete slabs. Shovel by shovel they create this random recipe for the next structural failure.
We might justify this construction method by saying things like:
* We only hire contractors who have been mixing on the ground for years.
* We mix on a piece of plywood to avoid contamination of the materials.
* We have tested our shovel mix at 2800 psi
Please let logic bring some clarity to this practice and ask a few questions:
Is the shovel volume the same every time? When the shovel folds the material over, does it move with consistency? Does the same volume of cement spread evenly over the entire mixing area? Is more water concentrated in some areas than others? Is the laborer tired, or is he weaker than others in the same mixing area? Did the bucket dip from a good mix of concrete or a weak spot?
This method of concrete mixing is like a rolling the dice in a poor man’s game of chance.
The hope for Haiti is the opportunity to build back better using the support of our donations. The generous donations of well-meaning people certainly do not want to see Russian Roulette by the bucket load.