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The impact of dewatering on lime mortars modified using brick dust was studied, as it is of particular importance in conservation applications. Dewatering takes place when freshly mixed mortars come into contact with a porous substrate, such as brick or stone, during on site construction. Since the dewatering process between the mortar and its subs...
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Context 1
... mass of the materials used were calculated from the values of their density to attain the anticipated mix proportions by volume. Table 1 summarises the components used in each mix design and their quantities. The proportions of binder and pozzolanic additions by volume were comparable with previously reported studies in the literature which have demonstrated their suitability for conservation applications [40]. ...Context 2
... It is worth noting that the water content of each mortar mixture was determined to establish constant consistency of control, 1/4P and 1P mortars which is demonstrated to be 130 mm in Fig. 3a. Due to the increase in the total solid fraction of the mixture from control to 1/4P then to 1P, the water content of the mortars, previously summarised in Table 1 have also systematically increased to attain constant consistence. The brick dust incorporation increases the transfer sorptivity of such mortars meaning that the mortars have become more water releasing when in contact with the dry substrate units. ...Context 3
... use of compressive strength as an indirect test method is a common procedure for the assessment of pozzolanic activity. In this study, pozzolanic brick dust was used within the hydrated lime mortars specified with lime:pozzolan:sand in the ratios of 1:1/4:2 and 1:1:2 and designated as 1/4P and 1P respectively, shown in Table 1. The strength difference between the control mortar and mortars with pozzolans (the 1/4 P and 1P) is indicated in Fig. 4. The rate of strength increases for 1/4P and 1P mortars, was higher up to 180 days. ...Citations
... Dewatering is governed by two main parameters: the desorptivity of the mortar and the sorptivity of the substrate [15]. When excessive water is removed physically by dewatering the capillary pore volume is decreased [31,32]. Alternatively capillary pores can also be reduced through the deposition of C-S-H phases evolved during pozzolanic reaction. ...
Degradation of hydrated lime mortars subjected to freezing and thawing is common in historic building conservation. The pozzolanic additions, Argical M1000, diatomite (diatomaceous earth) and brick dust, were evaluated for their ability to improve performance for up to 720 days. Pozzolanic reactions influenced the pore structure evolution, mechanical performance, and chemical reactivity of the mortar matrix. Argical-lime mortars exhibited a sudden failure, while a gradual reduction in mechanical strength was observed for mortars containing brick dust. A slower rate of failure in diatomite mortars was attributed to pore refinement, which was associated with superior freeze thaw performance. This study has advanced the current state of the art regarding how pore structure affects lime mortars' freeze and thaw resistance. Therefore it provides spesifications on how to optimise mortars for historic masonry. A key impact is the more effective use of lime mortars for conservation, thereby protecting heritage structures from degredation.
... The reductions in strength with pozzolans can be justified as the aggregate pozzolanic performance reducing when its fineness was smaller than the size of the aggregate. In addition, at early stages, the pozzolan had an almost single filler effect, and the greatest increase in the strength by pozzolanic reaction only was clearly observed at 180 and 850 days [53]. In the mixtures where there was no hydrated lime as binder, HS-B and HS-A, there was a sharp drop in the compressive strength, which, in a certain way, was already expected since pozzolanic materials were effectively efficient when combined with calcium hydroxide [51]. ...
... This indicates that these mixtures will have a larger open porosity that will facilitate water passage in the early stages of the test. Concerning the results with brick dust and ash mixtures, although other authors mentioned that the mortar matrix structure only became denser with the formation of the hydration components of pozzolanic activity, decreasing the porosity [53], in this case, the reduced absorption at an early age, also showed a filler effect on the voids. These materials mixes could act as water retainers once with the introduction of small pores that could cut the capillary network [58]. ...
... In general, the mixes maintained their shapes, resisted the cycles, and did not present cracks, but some samples ended up without binder coverage, with exposed fibers or lost part of the material. Concerning the results with brick dust and ash mixtures, although other authors mentioned that the mortar matrix structure only became denser with the formation of the hydration components of pozzolanic activity, decreasing the porosity [53], in this case, the reduced absorption at an early age, also showed a filler effect on the voids. These materials mixes could act as water retainers once with the introduction of small pores that could cut the capillary network [58]. ...
Bio-based materials help reduce the consumption of non-renewable resources, contributing to the development of sustainable construction. Industrial Hemp Concrete (IHC), which uses hemp stalk (HS) as an aggregate and a lime-based binder, is a bio-based material with various applications. This research developed a new hybrid composite in order to improve the mechanical strength and durability of hemp concrete, with the incorporation of sugarcane bagasse (SCB) as an aggregate, a resource of a renewable origin that is abundant in several countries. Different formulations were used, which were molded and pressed manually, evaluating their cohesion and compactness. The performance of the developed hybrid composite was measured considering mechanical, thermal, and durability properties. The compression test results showed an increase of 19–24% for composites with 75% hemp and 25% SCB. Thermal conductivity and thermal resistance coefficients were also improved, reaching 0.098 (W/m °C) and 0.489 (m2 °C/W), respectively. This aggregate combination also showed the lowest water absorption coefficient (reducing by 35%) and the best performance in durability tests compared to IHC. The resistance to freeze–thaw is highlighted, increasing 400%. The main reason is the influence of the SCB addition because the short and thin fiber form helps to maintain the physical integrity of the composite by filling the spaces between the hemp aggregates.
Bu deneysel çalışmada, çimento bazlı hamur ve harç karışımlarına yüksek oranda sönmüş hava kireci (SK) ve öğütülmüş yüksek fırın cürufunun (YFC) birlikte kullanımı ile üretilen numunelerin bazı fiziksel ve mekanik özellikleri araştırılmıştır. SK ve YFC ağırlıkça %10SK+%10YFC, %20SK+%20YFC ve %30SK+%30YFC oranlarında Portland çimentosu ile yer değiştirilerek hamur ve harç karışımları hazırlanmıştır. Üretilen harç karışımlarında işlenebilirlik sabit alınmıştır. Üretilen harç karışımlarından elde edilen fiziksel ve mekanik deney sonuçları kendi aralarında ve kontrol numuneleri ile karşılaştırılmıştır. Hamur numunelerde kıvam suyu, priz süreleri ve hacim genleşmesi deneyleri, harç numunelerde ise birim hacim ağırlık, basınç dayanımı ve eğilmede çekme dayanımı deneyleri yapılmıştır. Deney sonuçları, SK ve YFC’nin çimentoya ikame edilmesinin hamur kıvam suyu miktarını artırdığı, priz başı sürelerini azalttığı ancak priz sonu sürelerini artırdığı, birim hacim ağırlığı ve hacim genleşmesini ise azalttığı tespit edilmiştir. Ayrıca %30’a kadar SK ve YFC’nin birlikte ikame edilmesi, numunelerin 7, 28 ve 90 yaş gün eğilme ve basınç dayanımlarını azaltmıştır.
