On the theoretical carbon storage and carbon sequestration potential of hempcrete
On the theoretical carbon storage and carbon sequestration potential of hempcrete
复制标题
DOI：
10.1016/j.jclepro.2020.121846
复制
发表时间：
2020-09-01
影响因子：
11.1
通讯作者：
Srubar, Wil V., III
中科院分区：
文献类型：
--
作者：
Arehart, Jay H.;Nelson, William S.;Srubar, Wil V., III
大麻混凝土是一种天然绝缘材料，以其良好的热性能和低制造排放而闻名。大麻混凝土是一种生物复合材料，由大麻纤维和石灰基粘合剂组成，该粘合剂由熟石灰和水硬性粘合剂（例如天然水硬性石灰和普通硅酸盐水泥）或火山灰粘合剂（例如偏高岭土）组成。虽然可以通过在大麻混凝土中使用大麻纤维来实现长期的生物碳储存，但可以通过粘合剂的碳化来实现额外的碳储存。本研究通过推导基于水泥水化和碳化化学基础的理论模型来量化大麻混凝土粘合剂的总理论原位 CO(2)e 封存潜力，从而推进了先前的碳化建模方法。为了估计可通过原位粘结剂碳化回收的制造 CO(2)e 排放百分比，使用 U 值为 0.27 W/(m(2)K) 的 1 m(2) 墙体组件的等效功能单元 (FU)，对 36 种不同粘结剂含量和密度的大麻混凝土配方进行生命周期评估，实施该模型。我们的模型估计，与粘合剂生产相关的初始碳排放量的 18.5% 至 38.4% 可以通过原位碳化来封存。考虑到生物碳储存，我们预测大麻混凝土的总生命周期CO(2)e排放量可能为负，本文考虑的大麻混凝土混合物配方的最低为-16.0 kg CO(2)e/FU。然而，我们估计一些大麻混凝土配方可以表现出净正排放，特别是含有波特兰水泥的高密度混合物（> 300 kg/m(3)），从而说明了材料选择和配比在设计碳储存大麻混凝土中的重要性。
Hempcrete is a natural insulation material that is well known for exhibiting favorable thermal properties and low manufacturing emissions. Hempcrete is a biocomposite, consisting of hemp shiv and a lime-based binder composed of hydrated lime and either a hydraulic (e.g., natural hydraulic lime and ordinary portland cement) or pozzolanic binder (e.g., metakaolin). While long-term biogenic carbon storage can be achieved via utilization of hemp shiv in hempcrete, additional carbon storage can be achieved via carbonation of the binder. This study advances previous carbonation modeling approaches by deriving a theoretical model based on the fundamentals of cement hydration and carbonation chemistry to quantify the total theoretical in situ CO(2)e sequestration potential of hempcrete binders. To estimate the percentage of manufacturing CO(2)e emissions that can be recovered through in situ binder carbonation, the model is implemented in life cycle assessments of 36 hempcrete formulations of various binder contents and densities using an equivalent functional unit (FU) of a 1 m(2) wall assembly with a U-value of 0.27 W/(m(2)K). Our model estimates between 18.5% and 38.4% of initial carbon emissions associated with binder production can be sequestered through in situ carbonation. Considering biogenic carbon storage, we predict that the total life cycle CO(2)e emissions of hempcrete can be negative, with a minimum of -16.0 kg CO(2)e/FU for the hempcrete mixture formulations considered herein. However, we estimate that some hempcrete formulations can exhibit net-positive emissions, especially high-density mixes (> 300 kg/m(3)) containing portland cement, thereby illustrating the importance of materials selection and proportioning in designing carbon-storing hempcrete.