混凝土裂縫自癒合之研究

Abstract

本試驗係利用自養護劑為主，化學結晶劑為輔用於混凝土中，研究混合藥劑對混凝土力學性質、耐久性質及滲透性質等的影響。本試驗分為三個階段，第一階段藉由統整分析歷屆研究自養護混凝土之資料，而後施作不同水灰比的混凝土試體並找出可讓自養護藥劑發揮最大之效用，亦可讓化學防水劑產生效果之配比。第二階段為利用不同之養護環境，了解在固定配比的狀況下混凝土力學、耐久行為，並研究相互之關係。第三階段為將試體劈裂後進行滲透，觀察其癒合之成效。 研究結果顯示，自養護混凝土在硬固與濕養護時由於藥劑有良好的吸水及導水效能，可促進水化反應，較控制組能使強度提早成長，使混凝土在28天時即能達到控制組90天之強度，添加化學結晶劑在早期對強度增益較不明顯，標準養護下，其抗壓強度反而會低於控制組，而到養護中後期才漸與控制組追平。而在耐久性方面(電阻率、RCPT)方面，無論是空氣養護或是標準養護，自養護混凝土都優於控制組及其他各組，有效克服不良環境帶來的影響。試體癒合成效上，藥劑C組為自養護混凝土添加化學結晶劑，在癒合表現上優於其他各組，56天時最大癒合值可以達到2mm，而控制組較難觀察出有明顯癒合上之變化。 關鍵字：混凝土、自癒合、自養護

This study aims to develop self-healing concrete by using SCA (self-curing admixtures) and other chemical materials. There are three stages. The first stage is to find out the best SCA type and dosage to be used with water-proofing admixtures. The second stage is to study the effect of curing condition under a fixed mix proportions to determine the mechanical properties and durabilities and the interaction of them. The third stage is to split the specimens and investigate the self-healing performance. The results showed that under wet curing condition, the combined admixtures can accelerate the strength development and reached 90 day strength of the controlled specimens at 28 days. The water-proofing admixture did not show similar results and the strength was even lower than the controlled group at early ages. On the durability test, the electrical resistance and RCPT of the SCA group showed better results than all other groups. On the self-healing, the combined SCA and water-proofing admixture showed the best results and can reduce the crack width by 2mm at 56 days.

Keywords: concrete ,self-healing, self-curing