Partnership for Advancing Technologies in Housing: An Integrated Program to Examine the Moisture-related Performance of Fiber-cement Composites

PATH：研究纤维-水泥复合材料水分相关性能的综合项目干湿循环对纤维-水泥复合材料的影响以及由此产生的损伤机制尚未得到广泛系统的研究。这种基础知识的缺乏限制了我们准确预测纤维水泥材料使用寿命的能力，也限制了我们选择纤维水泥复合材料的能力，这些材料在预期湿度波动的环境中表现出良好的性能。为了充分了解纤维膨胀/收缩对纤维-水泥复合材料体系的影响——纤维、周围脆性基质以及复合材料整体性能的变化，需要一个全面的研究计划。该综合研究项目将由土木工程的混凝土技术专家和造纸科技的纸物理学家组成的研究小组进行，其目标是将周期性水分变化引起的微观结构变化与纤维-水泥复合材料宏观力学性能的变化联系起来。所提出的研究目标是：(1)评估反复润湿和干燥（雨和热）循环对木纤维尺寸变化的影响，纤维/水泥浆界面的物理粘合，以及纤维与基体之间的粘合强度；(2)评估是否可以通过定制纤维加工来改善粘合。该提案包括制备特殊排列纤维水泥复合材料，这将为定性和定量微观结构分析提供更好的机会。

PATH: An Integrated Program to Examine the Moisture-related Performance of Fiber-cement CompositesThe effect of wet/dry cycling on fiber-cement composites and the resulting mechanisms of damage have not been the subject of an extensive systematic examination. This lack of fundamental knowledge limits our ability to accurately predict service lives of fiber-cement materials and our ability to select materials for fiber-cement composites which are expected to exhibit good performance in exposures where moisture fluctuations are expected. A comprehensive research plan is necessary to fully understand the implications of fiber swelling/shrinking on the fiber-cement composite system - the changes that occur in the fiber, surrounding brittle matrix, and the performance of the composite as a whole. The objective of the integrated research project, to be undertaken by a research team composed of concrete technologists from Civil Engineering and paper physicists from Paper Science and Technology, is to link changes that occur on a microstructural level as a result of cyclical moisture changes to the changes in macroscale mechanical properties of the fiber-cement composite. The goals of the proposed research are (1) to assess the effects of repeated wetting and drying (rain and heat) cycles on dimensional changes of wood fibers, physical bonding at the fiber/cement paste interface, and bond strength between the fiber and matrix and (2) to assess if improved bonding can be produced through tailoring the fiber processing for this application. The proposal includes preparation of special aligned fiber cement-composites that will offer improved opportunities for both qualitative and quantitative microstructural analysis.