Preparation And Properties Of Slag/Metakaolin Based Geopolymer Materials

Slag/metakaolin based geopolymer material is a new kind of inorganic material, which includes two parts, the characteristic structure of cement-C-S-H-(silicate hydrate) and a three-dimensional network structure of geopolymer-Si-O--Al-O unit. It has many advantages, such as broad source of raw materials, low energy consumption, low pollu tion, simple preparation technology, rapid hardening, early strength and low dry shrinkage and so on. Compared with the traditional cement, it is a material with good application prospect since it is fully consistent with the policy of adjusting and optimizing industrial structure and strengthening the though outline of construction of ecological civilization, which are referred in the "Thirteenth Five-year" plan. Using blast furnace slag, metakaolin, sodium silicate, sodium hydroxide solution, quartz sand and deionized water as raw materials, this thesis investigated the preparation and properties of slag/metakaolin based geopolymer materials, lightweight foam materials of slag/metakaolin based geopolymer materials, and fiber-toughening geopolymer materials by the method of alkali excitation. After system optimization of processing parameters, the following main results were obtained:For the slag /metakaolin based geopolymer materials, when m(MK)/m[(MK+ BFS)]=0.25, modulus of sodium silicate is 1.3 and water glass content is 20wt%, quartz sand content is 15wt%, liquid-solid ratio of 0.7, curing temperature of 70?, curing time of 12 hours, the geopolymer materials have optimal performance with seven-day compressive strength of 97.86 MPa, which can be used to be road repair materials.For the lightweight foam materials of slag/metakaolin based geopolymer, when m(MK)/m[(MK+ BFS)]=0.35, hydrogen peroxide content is 1.6 ml, water glass content is 25wt%, stable foam agent content is 0.5wt%, liquid-solid ratio is 0.85, firstly room temperature curing for 2 h, followed by holding at 70 ? for another 12 h, the lightweight foamed materials have optimal performance with compressive strength of 6.76 MPa and bulk density of 0.61g/cm~3 and the coefficient of thermal cond uctivity of 0.103 W/( m·k), which have better heat preservation and heat insulation effect.For the HPMC and fiber toughening geopolymer materials, when m(MK)/m[(MK+BFS)]=0.25, HPMC content is 0.2wt%, polyacrylonitrile fiber content is 0.8wt%, water glass content is 20wt%, fine aggregate content is 15 wt %(where quality ratio of the fine sand and coarse sand is 3:1), liquid-solid ratio is 0.9, curing temperature of 70 ?, curing time of 12 hours, the toughening geopolymer materials have optimal perfor mance with compressive strength of 106.79 MPa and flexural strength of 12.16 MPa, which can be developed for construction wall material.