粉煤灰掺量对软岩地区喷射混凝土建筑性能影响研究

Study on influence of fly ash content on performance of shotcrete building in soft rock area

为探究粉煤灰掺量对软岩地区喷射混凝土建筑性能的影响,以某软岩地区建筑工程为参考,选择P.O 42.5普通硅酸盐水泥和Ⅱ级粉煤灰为主要材料,结合其他辅助材料制作了5种粉煤灰掺量的混凝土拌合物,将拌合物分别制成混凝土喷射到建筑试样中,即试样1~试样5,对5个试样的抗压强度、弹性模量及泌水率等进行试验。结果表明:粉煤灰的掺加质量分数在30%以内时,可保证试样的和易性和凝结时间调节性最佳;氯离子的表观扩散系数和即时扩散系数的最小值分别为0.62×10^(-12)m^(2)/s和0.427×10^(-12)m^(2)/s;粉煤灰掺加质量分数为30%时,弹性模量最高,为41.6 GPa;泌水率最高,为5.2%。

In order to explore the influence of fly ash content on the performance of shotcrete building in the soil area,taking a construction project in a soft rock area as a reference,P.O 42.5 ordinary Portland cement and classⅡfly ash were selected as the main materials,combined with other auxiliary materials to produce five kinds of concrete mixes with different fly ash contents,and then the mixes were made into concrete and sprayed into building samples.Namely,samples 1-5,the compressive strength,elastic modulus and bleeding rate of the 5 samples were tested.The results showed that the workability and setting time adjustability of the sample could be ensured when the fly ash content was less than 30%.The minimum values of apparent and immediate diffusion coefficients of chloride ions were 0.62×10^(-12) m^(2)/s and 0.427×10^(-12) m^(2)/s respectively.When the mass fraction of fly ash was 30%,the elastic modulus was the highest,being 41.6 GPa,and the bleeding rate was highest,being 5.2%.