科研之友
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摘要
The quarrying of marble, a well-known ornamental stone, has a substantial positive impact on Portugal's economy, but it also generates large environmental impacts. The amount of waste produced during quarrying can be as much as 80% of all stone/soil extracted. That waste is then dumped near the quarry, where it accumulates indiscriminately because a viable alternative for its disposal has not yet been found. In this context, solutions must be found that can transform this waste into a by-product and restore some of its economic value. The main goal of this study was to evaluate the influence of the replacement of primary aggregates (PA) with marble aggregates. No additions or admixtures were used, as those could change the fresh or hardened properties of the resulting concrete and disguise the influence of the replacement under study. This evaluation required the production of three concrete families. The conventional primary aggregates (PA; basalt, granite and limestone) were replaced in the three families by coarse marble aggregates (CMA) at ratios of 20%, 50% and 100% of the total volume of aggregates. These mixes were tested in the concrete's fresh state for workability and density and in its hardened state for compressive strength, water absorption by capillarity and immersion, carbonation and chloride penetration. The results indicate that there are no significant differences between a concrete produced using CMA and one made with PA in terms of durability, making the use of this waste as concrete aggregate perfectly feasible. The mechanical properties of the concrete made with CMA were assessed in the scope of concurrent work also performed at the Instituto Superior Tecnico (Lisbon, Portugal).
- 出版日期2014-2-15
