Natural lime concrete
for fine ruled finish floors
Ingredients
350-400 kg of Saint-Astier® NHL 5 or 300-350 kg of HL 5 (Hourdex® or Tradiblanc®) per cubic metre of aggregates consisting of 1 part sharp sand to 2 parts fine sharp sand.
Mixing
Mix dry to achieve a uniform colour in a pan mixer or roller pan mill. Slowly add clean water until the correct moisture is achieved (semi dry) – just sufficient to allow mix to bind when squeezed in hand. Free fall mixers can cause balling. Mixing time at least 10 minutes. Should not exceed 15 minutes.
Laying
The concrete is placed in a single consistent layer of 10 to 25 mm. It should be well rammed either by hand or with a vibrating screed to the desired level. Lay green on green.
Finishing
Tighten in the surface with a cross-grained wood float to a level plane, polish after initial stiffening with a steel float if desired. Lining out or ruling after 12 hours. A trial panel should always be done before attempting large areas.
Curing
In dry conditions, mist very lightly with clean water for 72 hours (twice a day at least during the first 48 hours and once a day the following 7 days). Protect from extreme heat, freezing, excessive wind, strong direct sunlight and rain. Ambient temperature range should be 8°C-30°C with low to average humidity
Protection
Foot traffic should be avoided for 7-10 days depending on the weather. Cover with protective walkways 12 hours after placing. These should remain in place for at least 2-3 weeks or longer if possible.