Development of new material for geopolymer lightweight cellular concrete and its cementing mechanism

Lightweight cellular concrete (LCC) is widely used in engineering and construction because of its low density and good thermal and acoustic insulation capabilities. However, cement production, the cementitious material for LCC, consumes much energy and emits large amounts of CO2. Therefore, reducing cement consumption is one of the main hot issues in the development of China's construction industry. The geopolymer cementitious material is one of the ideal substitutes for silicate cement because of its low energy consumption in production and its ability to give full play to the fly ash and slag activity under the action of alkali excitation. It is imperative to combine geopolymer with LCC to find a kind of lightweight and high strength building material, but there is still a lack of systematic research on this aspect. On the basis of exploring samples of geopolymer lightweight cellular concrete (GLCC), the influence of fly ash, slag content, sodium silicate modulus, alkali content, water cement ratio and other factors on the strength and fluidity of GLCC was analyzed by single factor (SF) test, and the reasonable value range of four factors was proposed. The significant effect of the four factors and the best matching ratio was derived through response surface (RS) test, and RS optimization prediction and validation were carried out. On the other hand, the cementing mechanism of geopolymer on LCC was analyzed from a microscopic perspective by comparing LCC and LCC filled with fly ash (LCCFFA) specimens with SEM tests.