"Billions of tons of cement are injected into the ground world-wide each year to increase ground strength and to create barriers to water flow. Examples of its use in construction include building foundations, reservoir dams and tunnel walls. This activity is termed 'permeation grouting'. Use of permeation grouts are recorded as far back 1802, when cement grout was injected into holes in the ground beneath a sluice at Dieppe to stabilise the foundations, which were failing. More recently, £5M was spent injecting over 42,000 tonnes of cement grout into the ground to stabilise mine workings for the construction of the Emirates Arena and the Sir Chris Hoy Veladrome for the 2014 Commonwealth Games in Glasgow. Whilst technology has substantially improved over the last two centuries, the basic principles of cement grouting have remained largely the same.
A key aim of this project is to revolutionise the grouting industry by developing the first 'detectable' grout. A fundamental issue with all grout injection is the inability to detect where the grout has gone once it has been injected into the ground. This lack of knowledge can result in significant grout wastage, drilling of unnecessary wells, a lack of data for efficient injection and an inability to detect 'gaps' in grout walls where containment of water is critical; for example in dams and surrounding waste disposal sites.
The ability to detect the location of grout beneath the ground, both during and after grout injection will transform industry practice. It will allow for more efficient design of grout walls, will reduce the risk of un-grouted 'gaps' in the rock through which water can leak, and will minimise the volume of cement needed. Cement production accounts for 5% of the worlds CO2 emissions to the atmosphere each year, hence this research will have a positive impact on meeting global climate emission targets."
"We are looking to replace traditional cements for sealing cracks in rocks to create barriers to water flow. Cements have a high carbon footprint.
We have shown that we can use bacteria to precipitate minerals (calcium carbonate) to seal rock fractures instead. Calcium carbonate is natural mineral that is common the ground and is more environmentally friendly than cement."