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首页> 外文会议>Workshop on Cement and Concrete - Trends and Challenges; 20011107-20011109; Anna Maria Island,FL; US >FUTURE NEEDS IN CEMENT AND CONCRETE: A NATIONAL HIGHWAY PERSPECTIVE
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FUTURE NEEDS IN CEMENT AND CONCRETE: A NATIONAL HIGHWAY PERSPECTIVE

机译：水泥和混凝土的未来需求：国家高速公路的前景

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摘要

There are a number of factors driving the current and future requirements for concrete as well as other paving materials. First, on a national basis, the primary mode of paving operations is switching from new construction to repair, rehabilitation and reconstruction. Second, because of user demands, most activities will take place under a time constraint due to the need to minimize the disruption of traffic. Cements and concretes will therefore have to set and gain strength faster to enable early opening. Third, concrete mixtures continue to become more complex. Paving concrete typically employs Portland cement plus at least one additional cementitious or pozzolanic material. This complexity will likely only increase, while expertise within the DOTs is decreasing due to staff reductions and retirements. The responsibility for developing mixture designs and proportions is being assigned more and more to the contractor by the DOTs. The trend is towards performance-related specifications for paving concrete, which takes some of the burden off the DOTs, and also gives the contractor added freedom in the mixture design process. Despite the added complexity, the behavior of the cement and other concrete components must be compatible and predictable when combined. Fourth, performance and durability of the concrete cannot be sacrificed because of factors one, two and three. Finally, both initial cost and life-cycle costs of concrete paving should be reduced in order for concrete to maintain or enhance its standing as a competitive paving material.
机译：有许多因素驱动着混凝土以及其他铺路材料的当前和未来需求。首先，在全国范围内，摊铺作业的主要模式是从新建筑转换为维修，修复和重建。其次，由于用户需求，由于需要最小化业务中断，大多数活动将在时间限制下进行。因此，水泥和混凝土将必须凝固并更快地获得强度，以实现早期开放。第三，混凝土混合物继续变得更加复杂。摊铺混凝土通常使用波特兰水泥以及至少一种其他的水泥或火山灰材料。这种复杂性可能只会增加，而DOT内的专业知识却由于裁员和退休而减少。 DOT越来越多地将开发混合物设计和比例的责任分配给承包商。趋势是走向与混凝土性能相关的规范，这减轻了DOT的负担，同时也使承包商在混合物设计过程中拥有更多的自由度。尽管增加了复杂性，但结合时水泥和其他混凝土组件的性能必须兼容且可预测。第四，由于一，二和三因素，不能牺牲混凝土的性能和耐久性。最后，应降低混凝土铺路的初始成本和生命周期成本，以使混凝土保持或提高其作为竞争性铺路材料的地位。

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