Rapid assessment of life cycle CO2 absorption in conventional and carbonation-injected construction blocks, and microstructural characterization of carbonation-injected pavers

随着时间的推移，水泥基产品（如混凝土）在一个称为碳酸化的过程中吸收大气中的二氧化碳。 碳酸化有助于抵消与波特兰水泥生产相关的一些二氧化碳排放。 水泥生产过程中排放的二氧化碳约有一半来自石灰石的煅烧。 理想情况下，煅烧产生的所有CO2最终通过碳酸化作用被混凝土重新吸收 过程在大多数情况下，碳酸化从混凝土的暴露表面向内缓慢地进行， 几年，几十年，在罗马混凝土的情况下，千年。混凝土的碳化速率是 这是一个经过充分研究的参数，无论是从量化CO2生命周期吸收的角度来看，还是从 量化混凝土本身的使用寿命的观点，因为碳酸化可能是混凝土使用寿命的一个影响因素。 预埋钢筋锈蚀。尽管在腐蚀、碳酸化方面可能有害， 也是有益的，特别是当该方法被结合到新混凝土的早期养护中时。 加速的碳酸化已被证明可以提高抗压强度并降低渗透性。 碳化-喷射技术相对较新，但已在商业上用于混凝土 建筑砌块生产，并正在寻求扩大到混凝土摊铺机行业。然而，摊铺机 暴露于比建筑砌块更恶劣的使用环境，并且需要增强的耐久性。这 研究计划旨在更好地了解碳酸化注入如何影响微观结构， 混凝土摊铺机的性能。除了铺路机的问题，研究计划也解决这个问题 注入碳酸盐的区块比传统制造的区块吸收更多或更少的二氧化碳， 他们的服务寿命。对于碳酸盐注入区块，大部分碳酸盐化发生在前面，但碳酸盐化 随着时间的推移，反应继续发生。具体来说，该研究计划将确定碳酸化率为 传统的和碳酸化注入块在一个模拟自然的长期碳酸化室， 会持续几十年

Over time, cement based products such as concrete absorb atmospheric CO2 in a process called carbonation. Carbonation helps to offset some of the CO2 emissions associated with portland cement production. Approximately half of the CO2 emitted during cement production originates from the calcination of limestone. Ideally, all of the CO2 attributed to calcination is eventually re-absorbed by concrete through the carbonation process. In most cases carbonation slowly progresses from the exposed surface of the concrete inward over a period of years, decades, and in the case of Roman concrete, millennia. The rate of carbonation in concrete is a well-studied parameter, both from the standpoint of quantifying the life cycle absorption of CO2, and from the standpoint of quantifying the service life of the concrete itself, as carbonation can be a contributing factor in the corrosion of embedded steel reinforcement. Although potentially detrimental in terms of corrosion, carbonation can also be beneficial, especially when the process is incorporated into the early-age curing of fresh concrete. Accelerated carbonation has been shown to improve compressive strength, and reduce permeability. Carbonation-injection technology is relatively new, but has been adopted commercially for concrete construction block production, and is looking to expand into the concrete paver industry. However, pavers are exposed to harsher service environments than construction blocks, and require enhanced durability. This research program aims to better understand how carbonation-injection influences the microstructure, and hence the performance, of concrete pavers. In addition to the paver issue, the research program also tackles the issue of whether carbonation-injected blocks absorb more or less CO2 than traditionally-manufactured blocks over their service life. For carbonation-injected blocks, much of the carbonation occurs up front, but carbonation reactions continue to occur over time. Specifically, the research program will determine the carbonation rate for traditional and carbonation-injected blocks in a chamber that simulates the natural long-term carbonation that would occur over a period of decades.