Stabilizer and straddle tool holder for agricultural tractor without own stability.

摘要

A porous cement for use in well bores comprises 45-75% of a siliceous aggregate, 5-25% of sodium silicate having a sodium oxide/silicon dioxide ratio of 1.6-3.6, 1-6% of iron, lead or zinc oxide as insolubilizing agent, 0-1% of ammonium or sodium bicarbonate as accelerator, 0-3% of sodium silicofluoride, and 15-30% of water, the particle size of the aggregate, metal oxide, bicarbonate and silicofluoride being less than 4 mm (5 US mesh) and at least 10% of the aggregate particles being 0.074-0.149 mm (100-200 US mesh).