自密实混凝土与老混凝土粘结强度的直剪试验研究

以自密实混凝土(SCC)作为新混凝土材料,进行了新老混凝土粘结强度的直剪试验研究,考察了混凝土强度、界面剂和抗剪钢筋对粘结抗剪性能的影响,并与普通混凝土(NC)进行比较。试验结果表明,自密实混凝土与老混凝土的粘结性能优于普通混凝土,用粉煤灰水泥净浆作界面剂,能提高粘结面的抗剪强度。新混凝土强度会影响新老混凝土的粘结性能。而在界面上植入抗剪钢筋后,能大幅度提高了新老混凝土的粘结抗剪强度。根据试验结果,提出了自密实新混凝土与老混凝土粘结抗剪强度的计算式,以供实际加固工程参考。

Experimental research on direct shear behavior of adhesion of self-compacting concrete on existing concrete

With the self-compacting concrete(SCC)taken as the new concrete,the experiment research on direct shear behavior of adhesion between existing and new concrete are performed.Based on the test,the effects of specific factors on adhesive shear performance are investigated.These factors are as follows: strength of young concrete,interfacial agents and reinforced bar planting.And normal concrete(NC)is also selected as new concrete in order to compare with selfcompacting concrete.The results show that self-compacting concrete is bonded better with old concrete than normal concrete.The strength of new concrete can influence the bonding of new and existing concrete.As interfacial agent,the mix of cement and fly ash can improve the adhesive shear strength.After planted reinforced bar,the shear strength of new and existing concrete increases greatly.Based on the test result,an expression of shear strength of self-compacting concrete on existing concrete is presented for the reference to the strengthening of concrete structure.