关键词: 生物质灰渣;钙硅比;托勃莫来石;干燥收缩;加气混凝土砌块

Abstract: Biomass ash contains high SiO 2and CaO.It is mixed with cement,lime and so on according to a certain proportion to prepare biomass ash aerated concrete blocks.Calcium-silicon ratio of aerated concrete was adjusted to research its influence on hydration products, mechanical properties and microstructure by changing the relative content of biomass ash,fly ash and lime.Results show that with increase of calcium-silicon ratio,dry density of biomass ash aerated concrete blocks gradually increase. When the calcium-silicon ratio is 0.86, the intensity reached its peak, its compressive strength and flexural strength is 2.5 MPa and 1.8 MPa, respectively.And the production of tobermorite is also the largest.Dry shrinkage figure also shows that biomass ash aerated concrete blocks have excellent volume performance when the calcium-silicon ratio is 0.86, and its maximum dry shrinkage is 0.44 mm/m, better than national standard(0.5 mm/m).Electron microscopy map of hydration products shows that with increase of calcium-silicon ratio, hydration products morphology of biomass ash aerated concrete blocks transformed from elongated needle-like structure to lamellar structure.

Key words: biomass ash;calcium-silicon ratio;tobermorite;dry shrinkage;aerated concrete block