Study of Influencing Factors on Compressive Strength of Alkali-Activated-Slag Concrete

• Main Authors: Kuan-Ming Chen, 陳冠銘
• Other Authors: Ta-Peng Chang
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/z2tn72

碩士 === 國立臺灣科技大學 === 營建工程系 === 105 === In this study, the solutions of sodium hydroxide and sodium silicate were used as the alkali activator to activate slag to make the alkali-activated cementitious binder, which was in turn used to produce the activated slag concrete. The parameters of water-solid ratio and the dosages of activator, silicon-sodium ratio in mix proportion were changed to investigate their effects of various combinations of parameters on physical properties and compressive strength of the alkali-activated slag concrete. The research results show that: (1) The slump of fresh alkali-activated slag concrete was in the range from 220 to 270 mm, and the slump flow was in the range from 370 to 660 mm, and the increase of water-solid ratio can improve the flowability of alkali-activated slag concrete. Experimental results showed the water in the mix proportion will directly affect the workability. (2) The increase of dosages of activator could enhance the material strength such that the compressive strengths of all mixture at 28 days were in the range from 21.37 to 52.29 MPa. An increase of 2% of activator could increase the concrete compressive strength at 28 days by 11 to 27%.(3) The thermal conductivities of all mixtures were in range from 0.754 to 1.53 W/m•K being slightly lower than those of original Portland cement concrete in range from 0.754 to 1.53 W/m•K. The alkali-activated slag concrete of water-solid ratio of 0.5 had relatively better insulation properties. (4) When the dosage of sodium hydroxide and sodium silicate was increased by 3.0 wt% and 1.0 wt%, respectively, the resulting water absorption of alkali-activated slag concrete at age of 28 days reduced by 0.35% 1.13%, respectively. Hence, the more used dosage of alkali solution caused the hydration product to form more C-S-H gel such that the resulting alkali-activated slag concrete had less internal prorsity. (5) The correlation coefficients for the proposed seven different types of mathematical regression models based on independent variables from seven different combinations of influencing factors were in the range from 0.42 to 0.8, in which the seventh model being based on the independent variable from the combination of total amount of silicon, sodium and water can get the optimal regression results.