Fuel Flow in Concrete Around Joints at Petrol Stations

At petrol stations, fuels are filled as liquids hazardous to water. Thus, the legal requirements of the Water Resources Act and the Plant Ordinance must be fulfilled when handling water-polluting substances in conjunction with other planning and regulations as well as general building authority approvals. The road surfaces at filling stations at petrol stations are in many cases made from a liquid-tight concrete (FD concrete) in accordance with the planning principles of the DAfStb guideline "concrete construction when handling water-polluting substances", planned, produced and operated in in-situ construction .

The FD concrete described in this guideline seals the concrete surfaces of filling stations at petrol stations by a limited penetration depth of water-polluting liquids into the concrete. The sealing surfaces at filling stations are considered to be leakproof if the penetration depth of the pressurised medium is less than 2/3 of the existing slab thickness. For filling station surfaces made of FD concrete, for example, a maximum characteristic penetration depth of 64 mm is to be applied for the typical intermittent admission of petrol to the concrete sealing surfaces. Due to the high characteristic penetration depth of fuels in FD-concrete, the verification of the joint convolution at the joint edge required in the approvals of the joint sealants for the required exposure time of 144 h with the typical joint sealants made of polysulphide cannot be carried out due to the limitations of the installation depth of the sealant.

The occurrence of liquids in the unprotected joint area below the joint, including a freight estimate, is to be clarified by specific investigations of exposed FD concrete on a joint.