Strength and permeability of boric acid-tempered ultrafine cement grouted sand

In this research, the groutabiliy of ultrafine cement (Ufc) grouts containing an additive of boric acid (BA) into the sand specimens with different particle size distribution and the engineering properties of grouted specimens were investigated. To begin with, the rheological characteristics of the neat UFC grouts having w/c ratios of 0.8, 1.0, 1.2, and 1.5 and those with 0.25, 0.50, 0.75, 1.0, 2.0, 3.0 contents of BA additive were determined. Later on, the groutability of various graded sand specimens were tested with the neat UFC and BA mixed grouts. Finally, the time-dependent strength and permeability tests were conducted on the successfully grouted sand specimen. With the addition of BA to UFC grouts, their setting times were extended but their viscosities, as well as their bleedings, were reduced. The groutability of UFC grouts was bettered with the addition of BA and the grouting pressure for the sand specimens was therefore reduced. The unconfined compressive strength (UCS) and the permeability of UFC grouted sand specimens were decreased with BA additive. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The research found that the addition of BA to UFC grouts can extend setting times, reduce viscosity and bleeding, improve flowability of UFC grouts, and decrease grouting pressure for sand specimens; however, it decreases the unconfined compressive strength (UCS) and permeability of UFC grouted sand specimens.