Development of Method for Measuring Residual Expansion of Cores Taken from Concrete Structures Affected by ASR

本研究提出了一种加速试验方法，用于早期判断受ASR影响的混凝土残余膨胀率。目前的方法是测量混凝土芯部的残余膨胀，不符合海水除冰盐等渗透混凝土并促进ASR的环境。因此，我们通过研究一种加速测试方法来解决这个问题，该方法将混凝土芯浸入NaOH或NaCl溶液中。得到了以下结果：1。贮藏温度的影响在低溶液浓度下贮藏温度过高时，r膨胀的影响较小，而在高溶液浓度下，r膨胀随贮藏温度的升高而增大。溶液种类及其浓度对asr膨胀的影响在低贮藏温度下溶液浓度过高时，asr膨胀较小，而在高贮藏温度下随着溶液浓度的升高而增大。浸在NaOH溶液中的岩心在早期产生的膨胀比浸在NaCl溶液中的岩心大。初始碱含量对混凝土膨胀率的影响初始碱含量越高的混凝土芯在NaOH溶液浸泡前的膨胀率越大。4、ASR对混凝土劣化程度的影响对于浸泡在NaOH溶液中的混凝土，试验开始前混凝土劣化程度越深，试验开始后堆芯的ASR膨胀越小。加速养护条件的提出基于研究范围内得到的结果，提出了一种早期判断混凝土残余膨胀率的加速养护条件。

This study developed an accelerated test method to judge the residual expansivity of concrete affected by ASR at the early stage. The current method, which measures the residual expansion of the concrete core, does not correspond to environments where seawater deicing salts, etc. penetrate concrete and promote ASR. Therefore, we addressed this problem by examining an accelerated test method with which the concrete cores were immersed in an NaOH or NaCl solution.The following results were obtained:1. Effect of Storage TemperatureASR expansion became small when the storage temperature rose excessively in the low solution concentration, but it increased with rising storage temperature in the high solution concentration.2. Effects of Kind of Solution and its ConcentrationASR expansion became small when the solution concentration rose excessively at low storage temperature, but it increased with rising solution concentration at high storage temperature. The core immersed in the NaOH solution generated larger expansion at the early stage than the core in the NaCl solution.3. Effect of Initial Alkali Content of ConcreteASR expansion of the core with a higher initial alkali content before immersion in the NaOH solution was larger.4. Effect of Degree of Concrete Deterioration due to ASRFor the concrete immersed in the NaOH solution, when the deterioration of the concrete had progressed more before the start of the test, the ASR expansion of the core after the start of the test became smaller.5. Proposal of Accelerated Curing ConditionBased on the results obtained within the range of this study, an acclerated curing condition was proposed to judge the residual expansivity of concrete at the early stage.