Anchorage Performance of Geopolymer-Grouted Rock Bolts

Abstract

This study investigated anchorage behavior of geopolymer-grouted rock bolts. Pull-out tests were conducted on rock bolts grouted by geopolymer mortar (GM), geopolymer paste (GP), and cement mortar (CM), respectively. The effect of grout, type of bolts, spacing of bolts, and anchorage depth on anchorage performance was examined. Experimental results have shown that GM achieves better bond than GP and CM under a constant water binder ratio of 0.4. Deformed bolts grouted by GM and GP exhibit a nominal bond strength 2.4 and 1.6 times higher than the plain round ones, respectively. Bolt spacing of more than 150 mm exerts little influence in the anchorage performance. Increasing anchorage depth contributes to both loading capacity and ductility, while reduces nominal bond strength of deformed bolts. The critical anchorage depth ensuring tensile failure of bolts is 12d for both GM-grouted and GP-grouted bolts. GM-grouted deformed bolts with minimum anchorage depth of 12d and bolt spacing of 150 mm are proposed for practical application.