Recycled Concrete Aggregates (RCA) are not enough used in the construction sector due to their high porosity and water absorption capacity. Fine particles which are composed of large amounts of attached hardened cement paste are even more difficult to valorize, while they could be used as mineral admixture in mortar or concrete. The objective of this work is to find a recovery track for this material as mineral addition. The use of a porous powder as mineral admixture in cementitious mortars raises the question of the effective water definition in such systems. Two powders are used, the first one is a grinded hardened cement paste (porous), and the second one is a limestone filler (non-porous). A comparison of the hydration degree, porosity, fresh, and hardened behaviors between cement pastes and mortars manufactured with the two powders is carried out. The results show that the porosity of the grinded hardened cement paste has an impact on the properties of cementitious materials. Depending on the studied properties (fresh or hardened properties), the substitution of cement by the porous powder could be done with, or without taking into account the water absorption. Taking into account the water absorption allows maintaining the fluidity of the mixture but decreases significantly the compressive strength for cement replacement percentages larger than 20%.

再生混凝土集料（RCA）由于其高孔隙率和吸水能力而不能在建筑行业中使用。由大量附着的硬化水泥浆组成的细颗粒甚至更难以估价，尽管它们可以用作砂浆或混凝土中的矿物掺合料。这项工作的目的是找到一种作为矿物添加物的回收途径。在水泥砂浆中使用多孔粉末作为矿物掺合料提出了这样的系统中有效水定义的问题。使用两种粉末，第一种是研磨的硬化水泥浆（多孔），第二种是石灰石填料（无孔）。比较水合度，孔隙率，新鲜度，并用这两种粉末制造的水泥浆和砂浆之间进行硬化行为。结果表明，研磨后的硬化水泥浆的孔隙度对胶凝材料的性能有影响。根据所研究的特性（新鲜或硬化特性），可以在考虑或不考虑吸水的情况下用多孔粉末替代水泥。考虑到吸水率，可以保持混合物的流动性，但是对于大于20％的水泥置换百分比，其抗压强度会大大降低。用多孔粉末代替水泥可以考虑是否吸水。考虑到吸水率，可以保持混合物的流动性，但是对于大于20％的水泥置换百分比，其抗压强度会大大降低。用多孔粉末代替水泥可以考虑是否吸水。考虑到吸水率，可以保持混合物的流动性，但是对于大于20％的水泥置换百分比，其抗压强度会大大降低。