Grouted dense skeleton concrete: Development and performance influence mechanism

Abstract

Grouted dense skeleton concrete is formed by grouting of cementitious paste to the pre-placed aggregate skeleton. This type of concrete is desirable for site conditions with restricted access of conventional concrete delivery and placement, however, the quality control is often challenging due to the difficulty in controlling the groutability. This study examined the desirable aggregate mixes by dividing the aggregate of 5–25 mm size range into four size fractions and blending them at various proportions to form the pre-placed aggregate skeleton. Grouted dense skeleton concrete mixes were produced with different combinations of aggregate size fractions and w/c (water-to-cement) ratios. The groutability, compressive and flexural strength, and durability in terms of electric flux and carbonation of the grouted dense skeleton concrete were measured. Quantitative analysis revealed that the groutability was governed by the paste flowability and the aggregate skeleton voids ratio, the compressive strength and electric flux were mainly governed by the concrete permeable voids ratio and aggregate skeleton voids ratio, and the flexural strength and carbonation depth were solely governed by the concrete permeable voids ratio. To produce grouted dense skeleton concrete with satisfactory fresh and hardened performance, aggregate skeleton with wide particle size range and paste with high flowability are advisable.