Mechanical properties of hydraulic lime mortars and fired clay bricks subjected to dry-wet cycles

Bompa, D.V.; Elghazouli, A.Y.

doi:10.1016/j.conbuildmat.2021.124458

Cited by 21 publications

(3 citation statements)

References 68 publications

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“…Mineralogical composition of representative mortars 1_NHL 3.5, 3_NCPV, 10_NCM, and 17_NCT (from Table 1 ) after 28 days of curing is summarized in Table 5 . Hardening of hydraulic limes is a combination of hydration, by the formation of a calcium-silicate-hydrate (C–S–H) and carbonation through the reaction between the portlandite and CO 2 from the atmosphere [ 29 ]. Presence of calcite and formation of C–S–H due to C 2 S hydration was confirmed in 1_NHL 3.5 mortar ( Table 5 ), although calcite was already present in the mineral matrix of NHL 3.5.…”

Section: Resultsmentioning

confidence: 99%

Mortars for Conservation of Late 19th and Early 20th Century Buildings—Combination of Natural Cements with Air Lime

et al. 2022

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With the availability of commercial Natural cements (NC) for the conservation purposes raises a fundamental question about the compatibility between historic and repair mortars. The properties of Natural cements are dependent on the geological location of the raw material extraction and also on the production parameters, both having an impact on the final properties of the mortars produced from each distinct. Therefore, the significance of preservation of 19th and 20th century heritage and selection of the proper binder compatible with the original materials necessitate the study of existing NCs, that nowadays are produced by several manufacturers. This work provides a complex study of the mortars prepared from three NCs available in the market: Groupe Prompt Vicat, France (NCPV); Cemento Collet Marfil (NCM) and Cemento Natural Tigre (NCT), both from Spain. Various mortar sets based on individual NC containing different binder/aggregate ratios and air lime additions were analyzed after 28, 60, and 90 days of curing with the focus on their mineralogical composition (XRD), morphology (SEM), mechanical (flexural and compressive strength), and physical properties such as water absorption by capillarity, water vapor permeability, and water vapor diffusion resistance. Mortars prepared from NCPV, NCM, and NCT show distinct physical-mechanical properties with varying binder/aggregate ratio and air lime addition. This study shows that the NC variability should be taken into consideration when selecting materials for the conservation and rehabilitation of historic renders and plasters. Based on the comparison with original NC mortars, several NC mortars developed in this study show adequate properties for conservation of the buildings from late 19th and early 20th century in terms of compressive strength (>12 MPa), water absorption by capillarity (<20 kg·m−2·h−0.5), water vapor permeability (<4 × 10−10 kg·s−1·m−1·Pa−1), and water vapor diffusion resistance (<28) values.

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Section: Resultsmentioning

confidence: 99%

Mortars for Conservation of Late 19th and Early 20th Century Buildings—Combination of Natural Cements with Air Lime

et al. 2022

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“…With the development of engineering construction, projects such as traffic slopes, hydropower reservoir bank slopes, and mine open-pit slopes are inevitably in a certain rainfall and groundwater environment [27][28][29][30][31][32][33][34]. The engineering rock mass is subjected to repeated dry and wet cycles, resulting in repeated damage and deterioration of the mechanical properties of the rock mass [35][36][37][38][39], exacerbating the creep effect of the engineering rock mass, which in turn affects the long-term aging stability of the engineering rock mass [40][41][42][43][44][45][46][47][48].…”

Section: Introductionmentioning

confidence: 99%

Study on creep mechanical properties of carbonaceous shale under dry-wet cycle

Wei¹,

et al. 2023

Phys. Scr.

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The creep mechanical properties of rock under dry-wet cycles are of great significance for studying the long-term aging stability of engineering rock and soil. In the past, there were few studies in this area, and most of the dry-wet cycle tests on rock samples did not conform to the actual stress state of the rock. In view of the shortcomings of these studies, this paper innovatively carried out the dry-wet cycle test of the rock under the continuous state of the stress field, and studied its mechanical properties. The specific method is to take carbonaceous shale as the research object, and use the soft rock shear rheological test system independently developed by our research group to carry out the shear creep test of carbonaceous shale under the action of dry-wet cycle. The test results show that the creep full-time curves of carbonaceous shale under different dry-wet cycles show a step-shaped curve shape. The dry-wet cycle has a significant effect on the deformation characteristics of carbonaceous shale. With the increase of the number of dry-wet cycles, the instantaneous strain of the rock gradually increases, the instantaneous shear modulus decreases from 596.650 MPa at 0 times to 365.199 MPa at 12 times, and the attenuation rate reaches 38.79 %. The creep strain and cumulative creep strain become larger, the stress required for accelerated creep decreases from 3.29 MPa to 2.75 MPa, and the accelerated creep time in the third stage increases from 11.892 h to 5.316 h, and the creep effect is more significant. The long-term strength of carbonaceous shale decreases from 3.05 MPa to 2.49 MPa, and the decrease increases with the increase of dry-wet cycles. The more the number of dry-wet cycles, the smaller the undulation of the shear failure section of the carbonaceous shale, and the smoother the surface. The research results have important guiding significance for the long-term aging stability analysis of engineering rock and soil mass subjected to repeated dry-wet cycles.

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“…This is largely related to the lower material properties compared to dry counterparts, yet at a different degree depending on the governing mechanisms (compressive crushing, shear sliding and diagonal cracking), and the level of interaction between them. A lower mortar strength is associated with a lower elastic modulus and compression masonry stiffness (Bompa and Elghazouli, 2021). In the presence of moisture, the in-plane elastic stiffness and diagonal tension strength can be reduced by more than 40% compared to dry conditions (Elghazouli et al, 2021b;Bompa and Elghazouli, 2022).…”

Section: Introductionmentioning

confidence: 99%

Seismic Performance of Heritage Clay Brick and Lime Mortar Masonry Structures

Elghazouli

Bompa

Mourad

et al. 2022

Springer Proceedings in Earth and Environmental Sciences

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This paper summarises recent investigations into the structural and material response of ambient-dry and wet clay-brick and lime-mortar masonry elements, with focus on those used in heritage structures in Historic Cairo. In addition to cyclic tests on largescale masonry walls subjected to lateral displacement and compressive gravity loads, the studies included complementary tests on small scale masonry panels and material specimens. It is shown that moisture can have a notable effect on the main material properties, including the shear and compression strengths, brick-mortar interaction parameters, and the elastic and shear moduli. The extent of the moisture effects is a function of the governing behaviour and material characteristics as well as the interaction between shear and precompression stresses and can lead to a loss of more than a third of the stiffness and strength in addition to a reduction in ductility. Simple and cost-effective strengthening techniques, using textile-reinforced meshes, for enhancing the lateral performance of lowstrength heritage masonry element, are also considered in this study. The effectiveness of the strengthening approach is illustrated and quantified through additional tests on the smallscale panels and large-scale wall specimens. It is shown that simple analytical assessment methods can be reliably adapted for predicting the response of the wall specimens, in terms of the lateral stiffness, strength and overall load-deformation behaviour.

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Mechanical properties of hydraulic lime mortars and fired clay bricks subjected to dry-wet cycles

Cited by 21 publications

References 68 publications

Mortars for Conservation of Late 19th and Early 20th Century Buildings—Combination of Natural Cements with Air Lime

Mortars for Conservation of Late 19th and Early 20th Century Buildings—Combination of Natural Cements with Air Lime

Study on creep mechanical properties of carbonaceous shale under dry-wet cycle

Seismic Performance of Heritage Clay Brick and Lime Mortar Masonry Structures

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