A STARTING MIX IS DECIDED ON

The recommended water:cement ratio is 2 : 1 for starting many of the grouting jobs.

         This is two parts of water to one part of cement, measured by volume.

However, if the majority of cracks are known to be relatively FINE such as 0.030in [0.75mm] or finer , starting with 3 : 1 could be better.

At the other extreme, If cracks are fairly WIDE such as 0.050in [1.25mm], it is usually wise to start with 1 : 1.

          Water : cement ratios are measured by volume in this programme.

          If additives are used in the grout, modifications may be necessary to these ratios.

The aim is to inject the thickest grout possible so as to get maximum durability with the grouting. The starting mix is usually followed by thicker mixes to achieve this.

The mixes should be reviewed during the grouting from time to time. Experience with the initial few holes in a fresh area helps with these reviews.

As shown on the next screen the grout is made up and put into the agitator. It is then pumped around the circulation line.