Concrete Experts Investigates Tipping Floor
The facility’s Owner processes municipal solid waste by receiving and unloading truck loads of assorted solid wastes onto a specially designed floor, called a ‘tipping floor.’ Once discharged, or dropped from the bed-height of a variety of truck types, onto the tipping slab, such wastes are examined by the Owner, sorted, and each type is finally pushed along the tipping floor surface using rubber tired loaders toward chutes which direct the sorted material to trucks waiting below. Thus, tipping floors experience extreme loads expected to wear in the normal course of operations.
Because of the extreme loads imposed on tipping floors from impact, sliding, abrasion, scraping, wheel and tire loads, and direct contact with solid waste, which is often accompanied by various potentially aggressive chemicals, such floors usually feature a top-most ‘wearing surface’ layer composed of a specialty material which is particularly hard, tough, chemically resistant, durable, and strong.
A specialized topping material failed prematurely. It was used as the exposed, 1" thick, working, upper surface of a slab specifically installed to armor an aggressively used industrial floor. Observed failure reportedly manifest early as “light-colored spots” or localized points somewhat uniformly present on the floor surface that became progressively larger. This was accompanied by unexpectedly rapid surface abrasion, wear and reduction of topping slab thickness. Separately, the coloration of the topping slab was variegated and blotchy, neither with any recognized pattern, in areas unrelated to the points of progressively enlarging distress. Similar, but unseen, failure reportedly occurred more or less simultaneously, and progressed at the bond line between the topping layer and its substrate. In some areas, the substrate was the concrete slab original to the facility, prepared to receive the topping slab. In other areas, the substrate was concrete fill material installed above the original concrete slab to reestablish elevations selected to achieve a generally uniform topping slab thickness.
BFI is a Concrete Expert Witness Firm that investigates concrete construction defects.