Development Of Acrylate Chemical Grouting Materials

Acrylate chemical grouting materials were widely used in seepage proof curtain and crevice repair in concrete work for its advantages such as low viscosity, good fluidity, and injective capability for tiny cracks. At present, however, most of the commercial products of acrylate grouting material have certain toxicities and do not meet the demands of environment conservation. In this term, to develop acrylate grouting materials with safety characteristic becomes a trend, which is also the origin of this thesis.Direct esterification was employed to synthesize two kinds of acrylic ester crosslinkers, namely ethylene glycol diacrylate (EGDA) and pentaerythritol diacrylate (PEDA). Impact factors such as catalyst content, reactant ratio, inhibitor content, temperature and reaction time were investigated to optimize the synthetic process. The optimum reaction conditions of EGDA were: catalyst 1.7% of the total mass, molar ratio of acrylic acid to ethylene glycol 2.5, inhibitor 0.6⁰.7 g/mol acrylic acid, and reaction mixture stirred at 90¹00℃for 5 h. For PEDA, however, the optimum conditions included: catalyst 2.0% of the total mass, molar ratio of acrylic acid to ethylene glycol 2.6, reaction mixture stirred at 105¹15℃for 4 h.Acrylate seriflux was obtained by introducing synthetic crosslinker to acrylate chemical grouting ingredient. Toxicity test was performed by Wuhan University Renmin Hospital according to standard process provided by GB 15193.3-2003. The test result claimed that our seriflux was non-toxic. Mechanical properties of the prepared seriflux were carried on according to the relative testing standards. The results showed that our acrylate seriflux had favorable features. For seriflux, the viscosity was 5.0⁶.0 mpa·s and the permeability coefficient was up to 10^-8 order of magnitude. After sand consolidation, the compressive strength of the sample was 0.506 MPa, and its destructive slope against forcing out was 930 Mpa/cm. Besides, the solid sample had dilatability in water.Acrylate chemical grouting gel was characterized by DSC, FT-IR and SEM, and its swelling ability and thermostability were studied. The results showed that Tg of our gel was low and increased with increasing crosslinker content. The crosslinker was involved in the formation of gel network, for there was no characteristic peak of alkene in the related IR spectrum. The gel had interconnected holes structure and when the crosslinker content increased, the number of holes increased as well as the diameter of holes minished. The crosslinker content also influenced the swelling rate and swelling degree of gel. The gel obtained had temperature sensibility, pH sensibility, and good thermostability.In order to further enhance the mechanical properties of acrylate grouting materials, white carbon black (WCB) was used as a reinforcing agent to prepare a chemical grouting material based on organic/inorganic composite. The introduction of inorganic item improved the performance of our grouting material. When adding 2% WCB, the compressive strength of sand consolidation sample based on composite grouting material was maximized to 0.562 MPa. Moreover, the advantages of original acrylate grouting materials were also kept in WCB-containing organic/inorganic composite.