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Reinforced masonry

Reinforced masonry is masonry with steel bars in grouted cores or cavities to carry tension and bending, used for retaining walls and higher-load blockwork under AS 3700.

By Dan Waring. Last updated 9 June 2026. Verified 9 June 2026.

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Reinforced masonry is masonry (usually hollow concrete block) with steel reinforcing bars set into grouted cores or cavities, so the wall can carry tension and bending, not just compression. Plain masonry is strong in compression but weak in tension; adding steel and grout lets it resist the bending loads from retained soil, wind, or out-of-plane forces. It is engineered under AS 3700.

How it works:

  • Hollow blocks are laid so their cores line up vertically (and bond beams run horizontally).
  • Vertical bars are placed in the cores and horizontal bars in bond-beam courses, lapped and tied per the engineer’s detail.
  • The cores and bond beams are then filled with grout (a flowable high-slump concrete), bonding the steel to the masonry so the two act together.

The result behaves much like a thin reinforced-concrete wall, but built in blockwork. That is why it is the standard solution for masonry retaining walls, higher walls, and load-bearing or wind-loaded blockwork where unreinforced masonry would crack or overturn.

For a builder the practical points are: it is an engineered element, so follow the structural drawings for bar size, spacing, lap lengths, and which cores are filled (not every core is necessarily grouted); keep the cores clean and aligned as you lay, because debris or misaligned cores stop the grout and steel doing their job; use a grout of the specified strength and slump so it actually flows down and fills the cores (a stiff mix bridges and leaves voids); and provide clean-out openings at the base on taller pours so you can confirm the cores are clear before grouting. Get the brickie and the grout pour sequenced with any inspection holds. For small-building work the simpler rules of AS 4773 may apply instead.

Also known as: Reinforced blockwork, grouted reinforced masonry.

Category: Materials / Masonry.

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References

Last updated: 2026-06-09. Verified: 2026-06-09. Quarterly review for currency.

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