Stabilisation of jointing sand in block paving

This paper discusses the problem of loss of jointing sand in block paving, how to avoid attendant loss of interlock, and possible damage to the pavement structure from ingress of water. Reasons for the erosion of jointing sand so far identified are: (1) Action of jet blast and propeller wash from aircraft engines; (2) Use of vacuum sweepers for cleaning block‐paving areas; (3) turbulent water flow over pavement surface; and (4) degradation and pumping of laying‐course materials. Various materials have been used to try to stabilize the jointing sand; some have provided a temporary solution to the problem. However, the most effective means of preventing erosion problems has been found to be the use of a specially formulated liquid prepolymer that retains elasticity after curing and is thus able to sustain the essential flexible nature of the block‐paving system.