Chemical and Microscopic Study of Masonry Mortar in Ancient Pagodas in East China

Ancient mortars played a crucial role in the construction of historical architectures due to their physical and chemical compatibility with traditional building materials such as stones and bricks. Therefore, the analysis and optimization of the ancient mortar formula are significant in the restoration and preservation of historical sites. In this work, 20 mortar samples selected from five ancient stone pagodas in Zhejiang Province, China, were analyzed. The results showed that mud, lime-soil mortar, lime-sand mortar, and lime-gypsum mortar were used as binders in these pagodas. The Ca(OH)₂/aggregate ratio ranging from 0.3 to 2.7 was usually used to prepare lime mortar. Protein and polysaccharide were also found in some samples.     

Potential Use of Foamed Mortar (FM) for Thermal Upgrading of Chinese Traditional Hui-Style Residences

The Hui-style residence is an important architectural heritage of China. The hollow wall structures are widely used to build its exterior wall system. However, the thermal performance of the hollow wall is no longer able to meet the new energy-saving and environmental requirement. This article describes a laboratory study of the development of foamed mortar (FM), with the potential for use in thermal upgrading of the Hui-style hollow wall system without dramatically changing its traditional structure. The key early age, physical, mechanical and thermal properties were systematically measured. Two extended models were respectively developed to calculate compressive strength and thermal conductivity, as a function of porosity. Environment chamber test was also employed to investigate the effectiveness of this novel thermal upgrading approach and the results show that filling the voids with FM can effectively improve the overall thermal resistance of the hollow wall system by 44%, which is almost equal to the overall thermal resistance when using the more expensive commercial inorganic stucco system. In addition, the combination of these two methods yielded an overall thermal resistance of 0.701 m²·K/W, which is even higher than 0.67 m²·K/W for the code required in the hot summer/cold winter climate zone.     

‘Frack off’: Towards an anarchist political ecology critique of corporate and state responses to anti-fracking resistance in the UK

This paper puts forward an anarchist political ecology critique of extreme energy extractivism by examining corporate and state responses (or ‘political reactions from above’) to anti-fracking resistance in the UK. The planned drilling for unconventional gas and oil through hydraulic fracturing has triggered unprecedented opposition, with protest camps, direct actions, and legal challenges disrupting operations and slowing down planning and exploration development. Drawing on green anarchist thought, critiques of extractivism, statism, and industrialism, and a (corporate) counterinsurgency framework, I examine the strategies adopted by drilling companies and state actors to manage resistance and win the ‘hearts and minds’ of the population, deploying tactics from greenwashing in local schools to harsh policing of dissent. The latter has included the criminalisation and stigmatisation of land defenders, targeting campaigners as ‘domestic extremists’, physical abuse, targeting protesters with disabilities, and entering public-private security partnerships with local police forces which involve the ‘outsourcing’ of police communication to drilling companies. Such actions are complimented by the contracting of PR firms, lobbying, sponsorships of sports clubs and school competitions, ‘astroturfing’, and influencing local so-called democratic procedures. This has gone hand in hand with political efforts to classify operation sites as ‘Nationally Significant Infrastructure projects’ to facilitate the suppression of protest. These strategies are embedded in a recently well-documented history of police infiltration and corporate spying, laying bare an unapologetic commitment to sacrifice human and nonhuman wellbeing for industrial growth, commitment to extractivist ideology and centralisation of power at the cost of further eroding local autonomy and control.     

天然水硬性石灰在不同碳化条件下的水化反应

为了探究不同碳化条件对天然水硬性石灰水化过程的影响,继而认识到养护条件中的碳化作用对天然水硬性石灰早期强度和养护时间的影响,模拟制备了不同碳化条件下的样品,用X射线衍射(XRD)、热重分析(TG)、红外光谱(IR)、扫描电子显微镜和X-射线能谱分析(SEM-EDX)测试和比较养护前后天然水硬性石灰成分、结构、形貌的变化。研究表明,天然水硬性石灰水化生成水化硅酸钙(CSH)、氢氧化钙(Ca(OH)_2)的反应与CSH、Ca(OH)_2的碳化反应同时进行,并且Ca(OH)_2的碳化速率大于水化反应生成Ca(OH)_2的速率。随着养护龄期增加CSH逐渐由细小的针棒状结构生长为粗大的棒状结构,随后又逐渐变短并最终完全碳化为方解石晶型的碳酸钙(CaCO_3)形貌。天然水硬性石灰水化产物的碳化作用能促进其水化反应进程。     

Qadhat—a comparative study of ancient and new lime mortar from the Marib province/Yemen

Qadhat is the name for a lime mortar in Southern Arabia. Its usage has a long tradition. This work describes physical and mineralogical properties of ancient, historical and new samples, which seem to have been produced the same way. XRD, thin sections and SEM analyses show the similarity of the material. It consists of aggregates of volcanic material that are rich in volcanic glass and lime as binder. The production process includes several hours of crushing the material, which produces fine-grained splinters of aggregates in the binder matrix and gives the mortar a high stability. A weathering test with sodium sulphate on different samples confirms that the stability of this mortar is the result of the production process.     

Characterization of lime mortar additivated with crystallization modifiers

Additivating mortars with crystallization modifiers is a novel approach to mitigate salt crystallization damage in historic masonry. Once verified the effectiveness of crystallization modifiers in bulk solution, the next step consists in verifying whether: (i) modifiers are still effective when mixed in mortar and going through the carbonation process and (ii) modifiers alter any mortar properties which might limit their application. This research addresses these issues for sodium ferrocyanide and borax, modifiers for sodium chloride, and sodium sulfate, respectively. Several experimental techniques have been applied to elucidate these questions. The results show that the selected modifiers are still able to alter the salt crystallization after going through the carbonation process of the mortar. Besides, no major effects of the modifiers on the fresh and hardened mortar properties were observed. It can therefore be concluded that there are no restraints for the future use of these crystallization modifiers in restoration mortars.     

Kinetic effect of carbonic anhydrase enzyme on the carbonation reaction of lime mortar

The effect of carbonic anhydrase enzyme on the precipitation kinetics and phase transformations of calcium carbonate, and on the strength development of lime mortars has been investigated with saturated lime solutions, lime pastes and lime mortars under atmospheric conditions. The results clearly show that carbonic anhydrase catalyzes the reaction between carbon dioxide and aqueous lime, and increases the rate of calcium carbonate crystallization, the yield of the carbonation reaction and mortar strength at early ages. This is most likely a kinetic effect associated with the increased rate of carbonate ions supply to the solution by the enzyme. In addition, this enzyme favors the formation of stable calcite and significantly modifies its morphology by developing new crystal faces. These results suggest a novel approach for accelerating the hardening of lime mortars using carbonic anhydrase enzyme, which may offer a potentially novel approach with significant benefits on the applications of lime mortars in architectural heritage conservation as well as in construction.     

Multi‐analytical Studies of Archaeological Chinese Earthen Plasters: The Inner Wall of the Longhu Hall (Yuzhen Palace,Ancient Building Complex,Wudang Mountains,China)

The Yuzhen Palace is one of the nine palaces in the Ancient Building Complex built by order of the Yongle Emperor during the Ming dynasty. The buildings were built with dressed black bricks. As a result of the planned national South–North Water Diversion project, the water level in the Danjiangkou Reservoir that surrounds the Yuzhen Palace was expected to rise by approximately 15 m. To avoid submersion of the site, three gates were elevated by 15 m in 2013 and other buildings dismantled, for later reconstruction. The characterization of the construction materials has therefore become of primary importance. Here, we present results on the plasters of the Longhu Hall. The analysis of materials involved a multi‐analytical approach combining optical and electron microscopy with X‐ray and vibrational spectromicroscopies and thermogravimetry. The results indicated the use of two earthen plaster layers and a whitewash finish coating applied over a thin preparatory intermediate layer to improve the adherence of the finish coating to the earthen plaster. Ramie and straw fibres identified in the earthen plasters were added to reduce shrinkage and cracking during drying. The raw materials used and the application technique pointed to a well‐established construction industry using traditional earthen building materials together with lime technology.     

Material Choices for Fibre in the Neolithic: An Approach through the Measurement of Mechanical Properties

Studies of the Mesolithic–Neolithic transition in Europe have focused on plants and animals exploited for food. However, the exploitation of plants for fibres underwent a significant change with the addition of domestic flax as a fibre crop. While the technology of flax fibre processing is increasingly understood by archaeologists, its material value as a fibre crop in comparison to indigenous fibre is less well explored. We examine the mechanical properties of flax and two indigenous fibres (lime bast, willow bast), by testing fibre strips for tensile properties and discuss the results in the light of material choices in these periods.