Abstract

Incorporating lightweight aggregate (LWA) in concrete decreases its density. The high porosity of LWA contributes to low density but also high absorption characteristics. LWA absorbs water even in a freshly mixed concrete mixture when their pore is not fully filled with water. On the contrary, an excessive saturation of LWA causes release of bleed water. Both situations make the concrete mixture unstable. Equilibrium in Laplace pressures between LWA and the surrounding cement binder determines the water absorption or desorption inside a fresh mix of lightweight aggregate concrete. A physical model derived from the pressure balance is proposed, and well predicts the water transport of LWA.

摘要

在混凝土中加入轻骨料 (LWA) 会降低其密度。LWA 的高孔隙率有助于实现低密度和高吸收特性。当 LWA 的孔隙未完全充满水时，即使在新混合的混凝土混合物中，LWA 也会吸收水分。相反，LWA 的过度饱和会导致渗水的释放。这两种情况都会使混凝土混合物不稳定。LWA 和周围水泥粘合剂之间的拉普拉斯压力平衡决定了轻骨料混凝土新鲜混合物内部的吸水或解吸。提出了从压力平衡导出的物理模型，并很好地预测了 LWA 的水运移。