粉煤灰及SAP对喷射混凝土早龄期开裂损伤影响

为系统研究粉煤灰、吸水保水剂(SAP)对喷射混凝土早龄期开裂损伤的影响,以掺入了粉煤灰、SAP的喷射混凝土为研究对象,对喷射混凝土的早龄期开裂损伤进行平板法试验研究。完成了各种试件的早龄期开裂损伤测试,研究了粉煤灰对喷射混凝土以及SAP对掺入20%粉煤灰喷射混凝土的早龄期开裂损伤的改善作用。试验结果表明,掺粉煤灰等量取代10%、20%水泥后,喷射混凝土的早龄期开裂损伤与基准喷射混凝土相比分别减小约7.2%和26.8%。掺0.25%SAP和0.5%SAP可以使20%粉煤灰掺量喷射混凝土的早龄期开裂损伤与基准喷射混凝土相比分别减小约57.9%和66.50%。因此,掺粉煤灰可有效地降低喷射混凝土早龄期开裂损伤,且在掺加粉煤灰的基础上再掺加适量的SAP效果会更佳。

On the Effect of Flyash and SAP on Shotcrete Early Age Cracking Damage

In order to systematically study the influence of flyash and super absorbent polymer(SAP) on the early age shotcrete cracking damage, taking shotcrete mixed with flyash and SAP as studying object, experimental study was carried out based on plate specimen method. Measurement of early age cracking damage for various specimens was completed. The improvement effect of flyash (mixed with pure shotcrete) and SAP (mixed with shotcrete with 20% flyash) on early age cracking damage was experimentally investigated, respectively. Experimental results manifest that under the condition of flyash amount in pure shotcrete is 10% and 20% respectively, the shotcrete early age cracking damage decreases by 7.2% and 26.8% respectively, compared with standard shotcrete; under the condition of SAP amount is 0.25% and 0.5% in shotcrete with 20% flyash respectively, the shotcrete early age cracking damage decreases by 57.9% and 66.5% respectively, compared with standard shotcrete. So, flyash can effectively reduce the shotcrete early age cracking damage, and the improvement effect of moderate amount of SAP mixed with shotcrete containing flyash is better than that of single flyash.