Currently, many countries around the world face serious problems related to coastal erosion. The use of natural fillers extracted from shallow areas as well as from rivers for coastal regeneration and beach nourishment generates additional environmental impacts that affect plants and animal communities, water circulation and coastal dynamics, amongst others. On the other hand, construction and demolition wastes (CDW) are becoming more abundant worldwide, generating additional environmental impacts related to water pollution due to leaching of contaminants, as well as loss of landscape quality. In this work it is proposed that CDW can be better suited to replace natural gravel for coastal erosion management. In addition, the use of CDW for beach regeneration will help to reduce the use of natural sources and thus to reduce the environmental impacts produced by extraction. This study investigates the physical characteristics of some fractions of construction and demolition wastes (CDW), particularly concrete, ceramics, asphaltic, and mixture material, to be used as filler to regenerate beaches, replacing the traditional filler generally used elsewhere. A wet ball milling method was used to adequate the physical characteristics (i.e. such as sphericity, roundness, and roughness) of the aggregates of CDW to be used for beach regeneration. The effects of the water mass to solid mass ratio (W/S), mass of sample to the mass of the balls (S/B), as well as ball milling time on the shape of CDW aggregates were studied. The optimum conditions to generate the required aggregates were W/S = 1, S/B = 0.5 and 1 h of ball milling. As particle size is considered an important parameter to avoid water turbidity, it is recommended to use particles with size greater than 2 mm, and the shape of the generated aggregates was calculated and compared to natural beach gravel. Wet ball milling significantly increased their roundness and contributed to a decrease of surface roughness, thus the final material presented high similarity with standard beach gravel aggregates. The durability of the material was also studied and compared to commercial gravel and beach gravel. The results show that weight loss during durability tests mainly depends on chemical composition of the CDW aggregates assayed. The chemical composition and mineralogical phase identification of CDW show the absence of hazardous elements and the presence of dolomite, quartz and calcite as principal phases. Inorganic composition of the CDW was also determined in order to comply with the Spanish Technical Instruction for the Environmental Management of Marine Extractions to obtain sand. Additionally, leaching tests of organic and inorganic substances were carried out according the European Standard EN12457/4 which specifies a compliance test providing information on leaching of granular wastes and sludges under specified experimental conditions, particularly a liquid to solid ratio of 10 L/kg dry matter for materials with a particle size below 10 mm (without or with limited size reduction). All generated aggregates complied with standard requirements, thus based on the satisfactory results produced by wet ball milling treatment on the physicals characteristics of CDW aggregates as well as on their chemical composition and results of the leaching tests, it is proposed the use of CDW as filler in beach and coastal regeneration.

目前，世界上许多国家都面临着与海岸侵蚀有关的严重问题。使用从浅水区和河流中提取的天然填料用于海岸再生和海滩营养会产生额外的环境影响，影响植物和动物群落、水循环和海岸动态等。另一方面，建筑和拆除废物 (CDW) 在世界范围内变得越来越丰富，由于污染物的浸出以及景观质量的损失，产生了与水污染相关的额外环境影响。在这项工作中，提出 CDW 可以更适合替代天然砾石进行海岸侵蚀管理。此外，使用 CDW 进行海滩再生将有助于减少自然资源的使用，从而减少开采对环境的影响。本研究调查了建筑和拆除废物 (CDW) 的某些部分的物理特性，特别是混凝土、陶瓷、沥青和混合材料，用作填充物以再生海滩，取代通常在其他地方使用的传统填充物。湿式球磨法用于使用于海滩再生的 CDW 聚集体的物理特性（例如球形度、圆度和粗糙度）充分。研究了水质量与固体质量比 (W/S)、样品质量与球质量 (S/B) 以及球磨时间对 CDW 骨料形状的影响。S  = 1, S/ B = 0.5 和 1 小时球磨。由于粒径被认为是避免水浑浊的重要参数，建议使用粒径大于 2 mm 的颗粒，并计算生成的聚集体的形状并与天然沙滩砾石进行比较。湿球磨显着增加了它们的圆度并有助于降低表面粗糙度，因此最终材料与标准沙滩砾石骨料具有高度相似性。还研究了材料的耐用性，并将其与商业砾石和海滩砾石进行了比较。结果表明，耐久性试验期间的重量损失主要取决于所测定的 CDW 骨料的化学成分。CDW的化学成分和矿物相鉴定表明没有危险元素和白云石的存在，石英和方解石为主要相。还确定了 CDW 的无机成分，以符合西班牙海洋开采环境管理技术指导以获取沙子。此外，有机和无机物质的浸出测试是根据欧洲标准 EN12457/4 进行的，该标准规定了一项合规性测试，提供有关在特定实验条件下浸出颗粒废物和污泥的信息，特别是液固比为 10 L/kg 干适用于粒径小于 10 毫米的材料（没有或有限地减小尺寸）。所有生成的骨料都符合标准要求，