<p>BF: Back filling behind abutments, wing walls and retaining walls with selected granular material (50:50 best quality picked brick chips &amp; sand of min. FM 1.00) of minimum 450 mm width, in layers of 150 mm thickness free from dust, impurities etc. including compaction using plate compactor, watering &amp; dressing, supply &amp; cost of all materials, carrying and labour, hire charge of plate compactor and other tools etc. all complete as per direction of the Engineer-In- Charge. Payment to be made for the compacted volume only for a compaction of 90% of the maximum dry density.</p>