Yang Sungchul, Lee Hyewon
School of Architectural Engineering, Hongik University, 2639 Sejong-ro Jochiwon, Sejong 30016, Korea.
Materials (Basel). 2021 Mar 17;14(6):1478. doi: 10.3390/ma14061478.
In the present study, a recycled concrete aggregate (RCA) coating treatment using a cement paste dissociation agent (CPDA) with different mixing methods was newly incorporated in RCA concrete mixtures. First, a preliminary test program was conducted to determine the proper dosage of the CPDA solution throughout its RCA concrete test results from compressive strength, flexural strength, and elastic modulus. Then, a series of experimental tests were carried out to investigate the effect of RCA coating treatment, different mixing method such as the equivalent mortar volume (EMV) method and conventional method, and different RCA replacement ratios on durability test results of RCA concrete such as drying shrinkage values and rapid chloride penetration test (RCPT) values. The test results showed that all RCA concretes mixed with the coated RCAs were found to be workable regardless of different mix methods, with the slump and air contents of all the mixes being almost identical. All the concrete specimens, which were mixed with the coated RCAs with CPDA solution, represented lower drying shrinkage and RCPT values than those mixed without RCA coating treatment, regardless of different mix proportioning methods or RCA replacement ratios. This holds for the concrete specimens proportioned with the EMV method, regardless of different RCA replacement ratios.
在本研究中，采用水泥浆体解离剂（CPDA）并通过不同混合方法对再生混凝土骨料（RCA）进行涂层处理，这是一种新应用于RCA混凝土混合料中的方法。首先，开展了一个初步试验项目，通过抗压强度、抗弯强度和弹性模量等RCA混凝土试验结果来确定CPDA溶液的合适用量。然后，进行了一系列试验，以研究RCA涂层处理、不同混合方法（如等效砂浆体积（EMV）法和传统方法）以及不同RCA替代率对RCA混凝土耐久性试验结果（如干燥收缩值和快速氯离子渗透试验（RCPT）值）的影响。试验结果表明，所有与经涂层处理的RCA混合的混凝土，无论采用何种不同的混合方法，均具有良好的工作性，所有混合料的坍落度和含气量几乎相同。所有与用CPDA溶液处理过的RCA混合的混凝土试件，无论采用何种不同的配合比方法或RCA替代率，其干燥收缩值和RCPT值均低于未进行RCA涂层处理的试件。对于采用EMV法配合比设计的混凝土试件，无论RCA替代率如何，均是如此。
