| Summary: | 博士 === 國立中央大學 === 土木工程研究所 === 99 === The polymer used in the cement matrix to improve its performance is seen as the development trends of organic and inorganic compound materials, and it also achieves some success. However, it is more important to integrate the connection between the generation and application of polymers than to research individually in the respective field. It can make the researchers in the organic polymer field understand better the needs of the users; relatively, it also makes the users in the inorganic cement matrix, who are originally strange to polymers, from the viewpoint of using effectiveness, offer some suggestions to achieve continuous rotation P (Plan) - D (Do) - C (Check) - (Action). It is a benign improving cycle that effectively improves the research interaction and enhances the products. In this study, acrylic ester is used for the medium, from series of planning, acquisition of the ester through basic reaction, to the analysis test assessment in the laboratory, and further improvement. In this way, we complete a good research cycle. In addition to the preliminary effectiveness, we also provide a good template.
The test results of powder-polymer mortar showed that the powder-polymer mixed with the accelerator had a 30-60 minute retarding effect, which could increase the flowability of modified mortar, especially for a long time (90 ~120 minutes) with the increasing flowability of 5 to 10%; in part experimental conditions, the polymer modified cement mortar had increasing effects on Flexural and compressive strength; the water-absorptivity and the water-absorbing expansion rate also effectively reduced. Besides, it was found, with different types and dosages of the superplasticizers which were mixed to control the equally initial fluidity, the powder- polymer would affect the effectiveness of the cement mortar.
From the esterification of acrylic acid and three different kinds of alcohols,ethanol, ethylene glycol and diethylene glycol, we got Poly Acrylic Ester (PAE). Through the powdered characteristics and the screening process of fresh mixed and hardened paste, the test results showed that glycol acrylate powdered polymer mixed with the accelerator had a 30-60 minute retarding effect, which could increase the flowability of fresh mixed mortar, especially for a long time (90 ~120 minutes) with the increasing flowability of 5 ~10%; the water-absorptivity and the water-absorbing expansion rate also effectively reduced. But it was not so good in strength, showing that the powdered polymer had certain restrictions when it was applied.
From the esterification of acrylic acid and five different kinds of alcohols,ethanol,ethylene glycol,diethylene glycol,lauryl alcohol and stearyl alcohol, we got Poly Acrylic Ester polymer in liquid. Compressive assessment test results showed that at the acid-alcohol mole ratio of 0.2, glycol acrylate polymer had the most effective modification,and the hardened properties were the best with the additive of 0.1%. Compared with the control group,after modification,the 28-day compressive strength of the modified cement paste,mortar and concret improved separately by 12.7%, 8.6% and 9.9%; the 28-day flexural strength and adhensive strength of the modified mortar improved separately by 10.0% and 73.9%；besides,the flowability of the modified mortar effectively increased by 9.8%, and 10.8% less water absorption; the dry shrinkages of different ages (length change) effectively decreased by 7.1%-14.5%, and the perventage of final weight loss of the soundness test decreased by 23.4%. In addition,in the supersonic velocity test, the velocity of the modified mortar improved by 6.9%, the dynamic elastic modulus by 33.3%, and in the rapid chloride ion penetration test (RCPT), 6-hour cumulative passing electricity of the 56-day-age specimen decreased by 19.8%, showing its promotion of durability and compactness. The SEM observation also confirmed that the PAE’s membrane formed in the modified cement matrix.
Purified by the three alcohols,ethanol,ethylene glycol and diethylene glycol,and through acid-alcohol ratio,temperature,time,catalyst and other parameters,we probed into the optimized study of purification. The comprehensive test results showed that we could get the best modified Glycol Acrylate and Diethylate glycol Acrylate with higher reaction temperature (90 ℃), moderate reaction time (60 minutes) and the right amount of concentration of catalyst (1% of the total weight of acid and alcohol). The best esterification rate is respectively 17.87% (at the ethylene glycol mole ratio of 0.271) and 19.66% (at the diethylene glycol mole ratio of 0.291 ). We got the best purification by adding 1.0% dose of hydrogen peroxide and Diethylate glycol Acrylate polymer had the most remarkable effect of modification by the additive of 0.1%. Compared with the control group,after modification,the 28-day compressive strength of the modified cement paste,mortar and concret improved separately by 14.8%, 15.1% and 14.1%; the 28-day flexural strength and adhensive strength of the modified mortar improved separately by 12.1% and 116.7%.Besides,the flowability of the modified mortar effectively increased by 6.3% less water absorption; the dry shrinkages of different ages (length change) effectively decreased by 36.2%~52.7%, and the perventage of final weight loss of the soundness test decreased by 15.4%. In addition,in the supersonic velocity test, the velocity of the modified mortar improved by 0.2%~5.9%, the dynamic elastic modulus by 33.3%, and in the rapid chloride ion penetration test (RCPT), 6-hour cumulative passing electricity of the 28-day-age specimen decreased by 2.82%, showing its promotion of durability and compactness. In the concrete fire damage kiln simulation experiments,the strength reduction of the specimen improved by 39.3%, also confirming that it could prolong the concrete resistant strength under high temperature.
Ultimately, the performance-cost assement results show that the optimized liquid polymer modified cement mortar, its performance-cost value is higher than that of ordinary Portland cement mortar, the highest or even up to 3 times.
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