Extend rest period and thermostatic period, increase thermostatic temperature also could reduce the dry shrinkage rate of standard curing concrete sand mortar, evidently improve its volume stability.

延长预养时间和恒温时间、提高恒温温度可以降低蒸养纯水泥砂浆的干缩率，使其体积稳定性得到明显改善。

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Concrete is a mixture of sand and cement.

混凝土是沙和水泥的混合物。

《牛津词典》

Sand DAMS, which are constructed out of concrete barriers 1-5m high and backfilled with sand, were voted as the best idea from five different proposals.

用混凝土护栏建造的1至5米高且用沙回填而成的砂坝从5个不同方案中脱颖而出，被选为最佳方案。

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Portland cement is a material that holds together the sand and crushed stone in concrete.

VOA: special.2009.12.01

The mine was shut down by the U.S. Mine Safety and Health Administration due to the unsafe buildup of sand and concrete material in the main shaft of the mine.

FORBES: Hecla's Lucky Friday Mine Rehabilitation Slightly Ahead Of Schedule, Restart In Early 2013

No production from the mine is expected this year after the federal Mine Safety and Health Administration ordered the Silver Shaft to be closed for removal of built-up sand and concrete material.

FORBES: Hecla Officials Anticipate Clean-Up Of Mine Shaft Can Begin In Few Weeks

The temporary closure of the Silver Shaft at the Lucky Friday mine was ordered last year by the federal Mine Safety and Health Administration for removal of built-up sand and concrete material.

FORBES: Update:Hecla Plans To Reopen Lucky Friday Mine In 1Q; Loss Reported In 3Q