As we continue to examine the issues that caused much of the crumbling rubble in Haiti, we discover more items that need attention. Concrete block production has become a major problem for Haiti’s reconstruction.
Much of the cement-based construction products have two common deficiencies; too little cement and poor blending of the raw materials.
Bad block continues to be produced and used to rebuild the country. But now there are organizations like CementTrust and AIDG who are attempting to change the quality of construction materials in the poorest regions of the world.
Peter Haas, who runs Appropriate Infrastructure Development Group (AIDG) has worked hard to improvement block production in Haiti and he shares a simple way to test the quality of a block.
“If you want to build a building here, you should get a block, hold it a meter and a half off the ground and drop it. If the block shatters, you don’t buy a block from the person. These are simple tests that the masons here didn’t know to do.”
Peter and others are training Haitian masons to do these simple tests in a way to avoid bad materials.
Peter continued his discussion on block by explaining that, “In Haiti a block is maybe an eighth of the weight of a concrete block that you’d buy in the U.S.”
A concrete block weighs about 42 lbs (19 kg) normally, so 1/8th equals only 5.25 lbs (2.39 kg) for a low quality block.
Unfortunately the Haitian’s will have a repeat performance of the current rubble piles unless they fix the blocks.
This solution starts with good education for trades people that teaches that good recipes are critical to the strength of the product.
CementTrust suggests that the next important component is the use of appropriate technology that blends the raw materials to effectively hydrate the cement. Until the cement and water combination coats the aggregates completely there will never be a consistently strong product.
These steps will be the only way to advance the quality of block and have most of the blocks pass the drop test. More importantly, we want the Haitian’s new homes to pass the earthquake and hurricane tests.
What do you think should be done to make better block?