In the Zoetermeer Bentwoud the Dienst Landelijk Gebied of the Ministry of Agriculture, Nature and Food Quality has experimented with six types of semi-pavement. The cheapest material there, concrete granulate, proved to be one of the best. This crushed and sieved concrete waste, sorted by size, appeared at first instance to be loose and dusty, but after a year it had hardened, solidified and was highly satisfactory, according to the Dienst.
Natuurmonumenten had previously constructed five experimental strips in the Dwingelderveld National Park, consisting respectively of flachkorn, KoMex, KFP-mix in two different grain sizes and duo-mix. The bike path in question is popular with recreational cyclists in summer. The five materials were judged, among other things, on ease of cycling, the degree of weed growth, innate recovery after wet or dry periods, sensitivity to frost and blending into the landscape. All materials proved to be somewhat affected by frost periods. Duo-mix and KFP-mix did not resist long droughts very well. In the end a slightly improved version of KoMex was preferred. KoMex contains three types of hammered stone, among others calcareous sandstone and a binding agent.