The formation and deposition of tufa precipitate from the leachate of the recycled concrete aggregate (RCA) within fibers of a nonwoven geotextile, as can potentially occur in a transportation infrastructure drainage system, is simulated in a laboratory environment. Two sets of modified column tests were conducted in this study with cycles of wetting and drying for 1 year in order to study the rate of RCA tufa precipitation. Results of measured changes in the infiltration capacities showed that, even with precipitated tufa, the RCA/geotextile system serviceability remains similar to the virgin aggregate (VA)/geotextile system at the end of the 12-month testing. Evaluation of the deposited tufa precipitation within geotextile samples showed that RCA tufa is dominated by calcite and gypsum minerals. Estimated quantities of RCA tufa deposition by existing models developed for natural environments, showed that they either grossly overestimate the observed behavior (calcite model) or underestimate it (gypsum model). Image analysis technique and chemical calculations based on leached dissolved solids were utilized successfully to develop models to predict the precipitation of RCA tufa in macroscales during the service life of a subdrain.

中文翻译：

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与再生混凝土相邻的暗渠中的化学堵塞和土工布适用性

在实验室环境中模拟了非织造土工织物纤维内再生混凝土骨料 (RCA) 渗滤液中石灰华沉淀物的形成和沉积，这可能发生在交通基础设施排水系统中。在这项研究中进行了两组改进的柱子测试，湿和干循环为 1 年，以研究 RCA 凝灰岩沉淀的速率。渗透能力的测量变化结果表明，即使使用沉淀的凝灰岩，RCA/土工织物系统的适用性在 12 个月的测试结束时仍与原始骨料 (VA)/土工织物系统相似。对土工织物样品中沉积的凝灰岩沉淀的评估表明，RCA 凝灰岩以方解石和石膏矿物为主。为自然环境开发的现有模型估计的 RCA 凝灰岩沉积量表明，它们要么严重高估了观察到的行为（方解石模型），要么低估了它（石膏模型）。成功地利用基于浸出溶解固体的图像分析技术和化学计算来开发模型，以预测在亚排水管使用寿命期间宏观尺度的 RCA 凝灰岩沉淀。