L-Box for Self Compacting Concrete
The L-Box test measures the ability of SCC mixes to flow between a set of obstructive bars. Final depth of the concrete at the gate and at the end of the trough is measured and the proportional difference expressed as a blocking ratio. Some test methods require timing the flow with a stopwatch.
The L-Box is constructed of durable stainless steel with welded joints and consists of a vertical hopper with a sliding gate at the bottom. There are three bars representing reinforcing steel and a horizontal trough in front of the gate. Fresh concrete is placed in the vertical hopper without consolidating. Lifting the slide gate allows the concrete to flow past the bars into the horizontal trough. The final depth of the concrete at the gate and at the end of the trough is measured and the proportional difference expressed as a blocking ratio.
The vertical section is of 200 x100 x600 mm and the horizontal section is of 700x200x150mm. Three 12mm Dia reinforcement bars are fitted at the base of horizontal section having gap of 40mm.