Method for absorbing and fixing carbon by using concrete porous aggregate and concrete

Abstract

The invention provides a method for absorbing and fixing carbon by using a concrete porous aggregate, which comprises the following steps: soaking the porous aggregate in a suspension containing non-corrosive ions of Ca2 and/or Mg < 2 + >, fully stirring and drying to obtain a pretreated aggregate; the porous aggregate is selected from one or more of coral aggregate, ceramsite aggregate and recycled brick aggregate; the porosity of the porous aggregate is 40-60%; and placing the pretreated aggregate in a closed environment, introducing CO2 gas for carbonization, and drying again to obtain the modified porous aggregate. According to the method, CO2 can be effectively stored in pores of the porous aggregate (accounting for about 20% of 1m < 3 > of concrete), and the situation that the pH value of a cement matrix is reduced due to carbon absorption and carbon sequestration in a conventional method is avoided, so that the adverse effect on concrete reinforcements is reduced. When the modified porous aggregate is applied to concrete, the carbon absorption amount of the concrete can be increased; the physical properties, such as the water absorption rate, are improved. 本发明提供一种利用混凝土多孔骨料吸碳固碳的方法，包括以下步骤：将多孔骨料浸泡在含Ca2和/或Mg2+的无腐蚀性离子的悬浮液中，充分搅拌后烘干，得到预处理骨料；所述多孔骨料选自珊瑚骨料、陶粒骨料和再生砖骨料中的一种或多种；所述多孔骨料的孔隙率为40～60％；将所述预处理骨料置于密闭环境中并通CO2气体碳化，再次烘干，得到改性多孔骨料。该方法能够有效地将CO2存储在多孔骨料的孔隙中(约占1m3混凝土的20％)，并避免采用常规方法吸碳固碳造成水泥基体的pH值下降，进而减小对混凝土钢筋造成的不利影响。改性多孔骨料应用在混凝土中，能够提高混凝土的吸碳量；提高其物理性能，如吸水率。