SGER: Are High Carbon Fly Ashes (HCFAS) Effective Stabilizers for Soft Organic Soils?

已发现水泥质C类粉煤灰以及其他胶结剂对于软质无机土壤是非常有效的稳定剂，但对于稳定软质有机土壤基本上无效。 然而，由PI开发的初步试验数据表明，软质有机土壤可以有效地用水泥质高碳粉煤灰（HCFAs）稳定，即，有机碳含量为3%的粉煤灰。 本SGER的目的是探索使用HCFAs稳定软有机土的可行性。 这个概念是新颖的，因为一个长期未解决的问题（软有机土壤的稳定）正在解决一个新的方法与材料（HCFA），目前填埋。这一概念也具有很高的风险，因为所开发的数据集非常有限，表明六氯环己烷确实是软质有机土壤的有效稳定剂。 然而，潜在的回报是巨大的。这项研究的成功结果可以使HCFAs成为稳定软质有机土壤的首选材料（迄今尚未解决的问题），促进可持续发展和可持续建筑实践，降低建筑成本，并通过减少填埋的飞灰量来改善环境。 有待检验的假设如下：（i）软质有机土壤可以有效地稳定与HCFAs和（ii）HCFAs中的有机碳是主要因素负责成功稳定的有机土壤与HCFAs。 一个由四个任务组成的研究计划，提出了测试这些假设。 这些任务包括三种软质有机土和三种HCFAs的物理和化学表征，它们代表了广泛的有机质（土壤）和有机碳（粉煤灰）含量，有机土和HCFAs混合物的无侧限压缩测试，微观结构分析，以评估这些混合物中的胶结作用，以及固化速率的评估，以间接评估有机物含量和有机碳含量如何影响胶结动力学。

Cementitious Class C fly ashes, as well as other cementing agents, have been found to be very effective stabilizers for soft inorganic soils, but are essentially ineffective at stabilizing soft organic soils. However, preliminary test data developed by the PIs has shown that soft organic soils can be effectively stabilized with cementitious high-carbon fly ashes (HCFAs), i.e., fly ashes with organic carbon content 3%. The objective of this SGER is to explore the feasibility of using HCFAs for stabilizing soft organic soils. This concept is novel because a long-standing unsolved problem (stabilization of soft organic soil) is being solved by a new approach with a material (HCFA) that is currently landfilled. The concept is also high risk, because a very limited data set has been developed showing that HCFAs are indeed effective stabilizers for soft organic soils. However, the potential rewards are substantial. Successful results from this study could make HCFAs the material of choice for stabilizing soft organic soils (a problem heretofore unresolved), foster sustainable development and sustainable construction practices, reduce construction costs, and improve the environment by reducing the volume of fly ash being landfilled. The hypotheses to be tested are as follows: (i) soft organic soils can be effectively stabilized with HCFAs and (ii) the organic carbon in HCFAs is the primary factor responsible for successful stabilization of organic soils with HCFAs. A research program consisting of four tasks is proposed to test these hypotheses. The tasks include physical and chemical characterization of three soft organic soils and three HCFAs that represent a broad range of organic matter (soil) and organic carbon (fly ash) contents, unconfined compression testing of mixtures of the organic soils and HCFAs, microstructural analyses to evaluate cementation in these mixtures, and an evaluation of curing rates to indirectly assess how the organic matter content and organic carbon content affect cementation kinetics.