and magnetic sand or ilmenite sand instead of common sea sand, concrete blocks can be obtained which have all the strength of the ordinary concrete blocks and which weigh, when immersed in water ...

Desert sand is too smooth to bind to make concrete, so sand is taken from river beds such as the Mekong A crisis is engulfing the Mekong River, its banks are collapsing and half a million people ...

You cannot have concrete without sand. River beds are being dug up across Africa to fuel a building boom, with little thought for what this means for the health of the river, and those who depend ...

Then cement, sand and water are mixed together to a crumbly ... mortar and use backer board instead when they can. But a ...

A cement bed, four to six inches thick, should be laid for all pavings, and there should be a thin layer of sand between such foundation and paving blocks. View Full Article in Timesmachine ...