INTERLOCKING BLOCKS AND INTERLOCKING PAVERS CURING PROCEDURES

Because of lack of training most people ignore or are unaware of the curing period and its importance and when the block fails the interlocking technology is blamed and subsequently gets bad press.

In interlocking blocks and interlocking pavers curing is the most important phase and poor curing practice is reason why the cement stabilized blocks fail.

Good curing practice is not followed for one of two reasons. Either the producer is not aware of the need for curing or it is felt that the cost of constructing a suitable curing area is not worth the potential increase in quality.

Experiments have shown that the strength lost due to poor curing can easily reduce the final block bulk strength by 20%. As the block surfaces lose water first, strength loss in these regions is still higher.

The loss of surface strength reduces both the handle-ability (edge and corner chipping during transport) and the durability of the blocks.

And when this happens clients interested in the technology get discouraged because of such cases. Some of the bad practices are blocks are frequently left uncovered and out in the sun to "dry”.

Cement relies on the presence of water to hydrate, forming an interlocking skeleton of calcium silicate hydrate which gives the material its strength.

• CGK1-20 mobile compressed earth block machine

If the interlocking blocks is allowed to prematurely dry then full hydration of the cement does not occur and consequently only part of the cement used contributes to the strength of the block.

If proper curing were implemented, maintaining the molding water content for at least 21 days, then both strength and durability improvements would be seen.

The curing area should be flat and a black polythene paper should be laid on the ground to receive fresh interlocking blocks and interlocking pavers from the press. If you want to reduce expenses you can always use the empty cement bags.

The curing shed doesn’t need to be unnecessarily expensive. It can be done using round timber poles and a shade net. The second hand shade nets are easily available in Naivasha at an affordable cost.

The best practice during the curing period is to water/irrigate the blocks twice a day, in the morning and evening for the 21 days. Always use a watering can when watering your blocks. During this time the blocks should be properly covered using the black polythene paper.