- Influence of the mechanical properties of lime mortar on the strength of brick masonry
- A. Costigan ; S. Pavía
- Book Title / Journal: Jan Valek, John J. Hughes and Caspar J. W. P. Groot, (Eds.), RILEM bookseries, Historic Mortars: Characterisation, Assessment and Repair, Springer New York,
- Year: 2013 , Volume: 7 , Series:
- Structure types ; Masonry Structures
- Description
- This paper aims at improving the quality of lime mortar masonry by
understanding the mechanics of mortars and masonry and their interaction. It
investigates how the mortar’s compressive and flexural strengths impact the
compressive and bond strength of clay brick masonry bound with calcium lime
(CL) and natural hydraulic lime (NHL) mortars. It concludes that the strength of
the bond has a greater impact on the compressive strength of masonry than the
mortar’s strength. The masonry compressive strength increased proportionally to
the strength of the bond up to 6 months. A regression analysis, giving a second
order equation with coefficient of determination (R2
) of 0.918, demonstrates a
strong and predictable relationship between bond strength and masonry
compressive strength. It was noted that CL90s mortar masonry reaching a high
bond value was stronger than that built with a stronger mortar but displaying a
poorer bond. Finally, the mechanics of lime mortars and their masonry are similar.
The predominantly elastic behaviour of the mortars of higher hydraulic strength
compares well with the elastic and brittle behaviour of their masonry, with either
little (NHL2) or non-existent plasticity (NHL3.5 and 5); in contrast, the CL90
mortar and masonry exhibit a plastic behaviour.
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- Mechanical properties of clay brick masonry bound with hydraulic limes and hydrated calcium lime
- A. Costigan ; S. Pavía
- Book Title / Journal: 8th International Masonry Conference 2010, Dresden, W. Jäger, B. Haseltine, A. Fried (Eds.)
- Year: 2010 , Volume: , Series:
- Structure types ; Masonry Structures
- Description
- Due to their physical and chemical properties, mortars made with lime are considered to be more
compatible with historic fabrics than those made with artificial cements. This paper explores the
mechanical properties of clay brick masonry bound with hydraulic limes of different strengths, and
hydrated calcium lime (CL90-s) with no hydraulic properties. Masonry wallettes built with a CL90-s
mortar and two natural limes of hydraulic strengths 3.5 and 5 MPa (NHL 3.5 and NHL 5) respectively
were tested for compressive and flexural strength. The strength of the bond between the mortar and
the brick was also measured. The paper concludes that CL mortar masonry displays a plastic
behaviour in compression while the mechanical behaviour of the HL mortar masonry is of a brittle
nature, with wallettes splitting along the centre, cracks above and below the vertical joints and spalling
of brick and mortar.
It also concludes that neither the rate of late strength gain of masonry, nor its ultimate compressive
strength or its bond strength are determined by the mortar nature, thus a mortar of low hydraulic
strength can provide stronger masonry than an emminetly hydraulic mortar. The paper agrees with
previous authors on that the masonry’s compressive strength is more sensitive to the brick-mortar
bond strength than to the compressive strength of the mortar. Finally, the paper demonstrates that the
NHL-mortar compressive strength increases at a higher rate, and reaches higher final values than
that of the NHLmasonry whereas, in contrast, the CL90-s mortar is weaker in compression than the
CL90-s mortar masonry.
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- Compressive, flexural and bond strength of brick/lime mortar masonry
- A. Costigan ; S. Pavía
- Book Title / Journal: Proceedings of PROHITEC 09, Rome, 2009, F. Mazzolani (Ed.), Taylor and Francis,
- Year: 2009 , Volume: , Series:
- Structure types ; Masonry Structures
- Description
- Due to their physical and chemical properties, mortars made with lime are considered to be more compatible
with historic fabrics than those made with artificial cements. This paper intends to contribute to the knowledge of the behavior of lime mortar masonry, by exploring the mechanical properties of clay brick masonry
bound with both hydraulic and non-hydraulic lime mortars. Masonry wallettes built with a (non-hydraulic)
low-strength, calcium lime binder (CL90-s) and a natural-hydraulic-lime of hydraulic strength 5 MPa. (NHL
5) were tested for compressive and flexural strength. The strength of the bond between the mortar and the
brick was also measured.
The results examine the relationships between the mortar properties and the ultimate strength results of the
two types of masonry tested. The paper also compares the mechanical behaviour of the two masonry types
under lateral and vertical loads and studies the modes of failure and their relationship with the mortar properties measured. The results were also compared with strength predictions of building standards.
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