At present there still cannot find a more cheap fiber materials instead of steel fiber, through the rubble to substitute partly mixing quartz sand to reduce the cost of RPC become necessary.

在目前还不能通过寻找一种更为廉价的纤维材料来代替钢纤维的情况下，通过掺加碎石来替代部分石英砂，以达到降低RPC的造价成为必要。

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Workers dug and blasted earth and rock to reduce everything to street grade, leaving mounds of rubble behind.

WSJ: The Greatest Grid | Museum of the City of New York | Crosshatching a Miracle | By Ada Louise Huxtable