Construction World April 2023

The shortage of natural sand, a non-renewable resource, is a growing environmental issue for concrete production.

CHRYSO CLEAR Test is an innovative and quick service from CHRYSO Southern Africa to analyse sand.

varying clay conditions in the source material at each of these. “With this customer, it made sense for them to standardise on using CHRYSO® Quad CLEAR®; not only could it solve the challenges arising where swelling clay occurred but, where this challenge was not present, it still delivered the required benefits such as water reduction and concrete flow,” he explains. The other area where concrete users could face challenges is regarding the fines content of their sand. Crusher sand will often have either too little or too much of this fine material and neither condition is ideal in achieving optimal concrete performance. “The solution in this situation is our CHRYSO® Quad GRAFT® (Gap Gradation Fixing Technology) which we also add to our plasticiser for applications where the customer encounters an excess or lack of fines in their source material,” says Flannigan. “Where natural sand is still being used in the mix as a filler, the proportion of this material can be reduced.” He concludes with the warning that climate change is likely to exacerbate the issue of challenging sands, and this is particularly so in countries like South Africa where increased flooding is likely to introduce more silt, clay and organic material into rivers – which are a key source of natural sand. 

CHRYSO Gap Gradation Fixing Technology allows the use of manufactured sand which contains fines levels that are either too high or too low. MEETING THE CHALLENGES OF SAND • CHRYSO® Quad CLEAR® (Clay Enabling Admixture Response) addresses the challenge of swelling clays in natural sand, which can inhibit the performance of plasticisers. • CHRYSO® Quad CLEAR® Test identifies swelling clays in sand to alert users to apply corrective action. • CHRYSO® Quad GRAFT® (Gap Gradation Fixing Technology) allows the use of manufactured sand which contains fines levels that are either too high or too low.

The CHRYSO Quad solutions significantly drive down sand procurement costs and the carbon footprint on transportation through using local resources.

29 CONSTRUCTION WORLD APRIL 2023