Chemical resistance of lime-based grouts for masonry strengthening

The stone masonry walls are present in many buildings and historical monuments, with undeniable asset value, but also in old buildings housing both in Portugal and in Europe. Most of these buildings in masonry are in certain cases in a high state of degradation needing urgent intervention. This requires the identification of deficiencies and the application of appropriate intervention techniques. One of the possible techniques for structural consolidation works of stone masonry walls is the injection of fluid mortars currently called grouts. The choice of grouts is very important with regard in particular to their chemical and physical properties. In this study, carried out under the Master of Chemical Engineering, two types of lime-based grouts were used, in order to evaluate and compare their chemical resistance due to the crystallization of soluble salts. One of the grouts is a pre-dosed blend commercially available, Mape-Antique I from company Mapei (CA), and the second grout is a mixture prepared in the laboratory (LB), comprising metakaolin, cement, hydrated lime, water and superplasticizer. With the purpose of evaluating the action of sulphates on these grouts, a series of samples underwent several wetting-drying cycles using two different temperatures, 20 °C and 50 °C. During the experiment it was determined the change of weight and compressive strength in the analyzed grouts, as well as the sulphate ion concentration and pH of the solution in which the samples were dipped. The commercial grout (CA) apparently has a greater chemical resistance to sulphates. However grout LB showed to have positive results in some parameters.

Life cycle inventory for Australian building materials

This paper discusses challenges to developers of a national Life Cycle Inventory (LCI) database on which to base assessment of building environmental impacts and a key to development of a fully integrated eco-design tool created for automated eco-efficiency assessment of commercial building design direct from 3D CAD. The scope of this database includes Australian and overseas processing burdens involved in acquiring, processing, transporting, fabricating, finishing and using metals, masonry, timber, glazing, ceramics, plastics, fittings, composites and coatings. Burdens are classified, calculated and reported for all flows of raw materials, fuels, energy and emissions to and from the air, soil and water associated with typical products and services in building construction, fitout and operation. The aggregated life cycle inventory data provides the capacity to generate environmental impact assessment reports based on accepted performance indicators. Practitioners can identify hot spots showing high environmental burdens of a proposed design and drill down to report on specific building components. They can compare assessments with case studies and operational estimates to assist in eco-efficient design of a building, fitout and operation.

Heritage refurbishment : National Trust House (Basement 3) [Architectural Practice Academy Office]

The refurbishment of The National Trust House (Basement3), undertaken in 2005, represents heritage consultation, architectural and interior design of a disused and deteriorating subbasement of a historically and culturally significant building situated in Brisbane. Research into rectification and restoration work of the existing structure and interior surfaces (inclusive of masonry work sourced from the Kangaroo Point quarry in the 1860's) formed a significant component of the project. The National Trust House sub basement 3 was refurbished to house the Architectural Practice Academy, a joint initiative of the Queensland Government and the Australian Institute of Architects.

Strength of lime-fly ash compacts using different curing techniques and gypsum additive

Lime-fly ash mixtures are exploited for the manufacture of fly ash bricks finding applications in load bearing masonry. Lime-pozzolana reactions take place at a slow pace under ambient temperature conditions and hence very long curing durations are required to achieve meaningful strength values. The present investigation examines the improvements in strength development in lime-fly ash compacts through low temperature steam curing and use of additives like gypsum. Results of density-strength-moulding water content relationships, influence of lime-fly ash ratio, steam curing and role of gypsum on strength development, and characteristics of compacted lime-fly ash-gypsum bricks have been discussed. The test results reveal that (a) strength increases with increase in density irrespective of lime content, type of curing and moulding water content, (b) optimum lime-fly ash ratio yielding maximum strength is about 0.75 in the normal curing conditions, (c) 24 h of steam curing (at 80A degrees C) is sufficient to achieve nearly possible maximum strength, (d) optimum gypsum content yielding maximum compressive strength is at 2%, (e) with gypsum additive it is possible to obtain lime-fly ash bricks or blocks having sufficient strength (> 10 MPa) at 28 days of normal wet burlap curing.

Low embodied energy cement stabilised rammed earth building-A case study

Rammed earth is a monolithic construction and the construction process involves compaction of processed soil in progressive layers in a rigid formwork. Durable and thinner load bearing walls can be built using stabilised rammed earth. Use of inorganic additives such as cement for rammed earth walls has been in practice since the last 5-6 decades and cement stabilised rammed earth (CSRE) buildings can be seen across the world. The paper deals with the construction aspects, structural design and embodied energy analysis of a three storey load bearing school building complex. The CSRE school complex consists of 15 classrooms, an open air theatre and a service block. The complex has a built-up area of 1691.3 m(2) and was constructed employing manual construction techniques. This case study shows low embodied energy of 1.15 GJ/m(2) for the CSRE building as against 3-4 GJ/m(2) for conventional burnt clay brick load bearing masonry buildings. (C) 2013 Elsevier B.V. All rights reserved.

Fiber Bragg Grating Sensor Package for Submicron Level Displacement Measurements

In this article, the design and development of a Fiber Bragg Grating (FBG) based displacement sensor package for submicron level displacement measurements are presented. A linear shift of 12.12 nm in Bragg wavelength of the FBG sensor is obtained for a displacement of 6 mm with a calibration factor of 0.495 mu m/pm. Field trials have also been conducted by comparing the FBG displacement sensor package against a conventional dial gauge, on a five block masonry prism specimen loaded using three-point bending technique. The responses from both the sensors are in good agreement, up to the failure of the masonry prism. Furthermore, from the real-time displacement data recorded using FBG, it is possible to detect the time at which early creaks generated inside the body of the specimen which then prorogate to the surface to develop visible surface cracks; the respective load from the load cell can be obtained from the inflection (stress release point) in the displacement curve. Thus the developed FBG displacement sensor package can be used to detect failures in structures much earlier and to provide an adequate time to exercise necessary action, thereby avoiding the possible disaster.

El régimen de alcaldías y veedurías en el concejo bajomedieval : el alcalde del alarifazgo en Jaén

En los años finales de la Edad Media nos vamos a encontrar en los municipios castellanos con una gran abundancia de oficios tanto de carácter jurisdiccional como fiscalizador (alcaldes y veedores, respectivamente), algunos tenían planta propia y estable, en tanto que otros aparecían y desaparecían de acuerdo con las necesidades del momento. Nos detenemos en particular en la figura del alcalde del alarifazgo, encargado de juzgar y ejecutar de acuerdo con sus competencias en el ámbito del urbanismo.

A study of the proposed Diamond Creek Reservoir

Politically the Colorado river is an interstate as well as an international stream. Physically the basin divides itself distinctly into three sections. The upper section from head waters to the mouth of San Juan comprises about 40 percent of the total of the basin and affords about 87 percent of the total runoff, or an average of about 15 000 000 acre feet per annum. High mountains and cold weather are found in this section. The middle section from the mouth of San Juan to the mouth of the Williams comprises about 35 percent of the total area of the basin and supplies about 7 percent of the annual runoff. Narrow canyons and mild weather prevail in this section. The lower third of the basin is composed of mainly hot arid plains of low altitude. It comprises some 25 percent of the total area of the basin and furnishes about 6 percent of the average annual runoff.

The proposed Diamond Creek reservoir is located in the middle section and is wholly within the boundary of Arizona. The site is at the mouth of Diamond Creek and is only 16 m. from Beach Spring, a station on the Santa Fe railroad. It is solely a power project with a limited storage capacity. The dam which creats the reservoir is of the gravity type to be constructed across the river. The walls and foundation are of granite. For a dam of 290 feet in height, the back water will be about 25 m. up the river.

The power house will be placed right below the dam perpendicular to the axis of the river. It is entirely a concrete structure. The power installation would consist of eighteen 37 500 H.P. vertical, variable head turbines, directly connected to 28 000 kwa. 110 000 v. 3 phase, 60 cycle generators with necessary switching and auxiliary apparatus. Each unit is to be fed by a separate penstock wholly embedded into the masonry.

Concerning the power market, the main electric transmission lines would extend to Prescott, Phoenix, Mesa, Florence etc. The mining regions of the mountains of Arizona would be the most adequate market. The demand of power in the above named places might not be large at present. It will, from the observation of the writer, rapidly increase with the wonderful advancement of all kinds of industrial development.

All these things being comparatively feasible, there is one difficult problem: that is the silt. At the Diamond Creek dam site the average annual silt discharge is about 82 650 acre feet. The geographical conditions, however, will not permit silt deposites right in the reservoir. So this design will be made under the assumption given in Section 4.

The silt condition and the change of lower course of the Colorado are much like those of the Yellow River in China. But one thing is different. On the Colorado most of the canyon walls are of granite, while those on the Yellow are of alluvial loess: so it is very hard, if not impossible, to get a favorable dam site on the lower part. As a visitor to this country, I should like to see the full development of the Colorado: but how about THE YELLOW!

Estado de conservación de los elementos constructivos del Palacio Guevara (Segura - Gipuzkoa)

107 pag.

Correio Braziliense: um olhar sobre a sociabilidade maçônica (1808-1822)

O presente trabalho propõe apresentar o tipo de sociabilidade maçônica idealizada por Hipólito José da Costa, redator do Correio Braziliense (1808-1822), pioneiro da imprensa brasileira, apesar de não ser um reconhecimento unânime. Dessa forma será enfatizado à trajetória de vida de Hipólito e as muitas memórias construídas por seus biógrafos, que trazem à luz as dubiedades que cercam a figura do redator luso-brasileiro. Algumas interpretações que abordam as inúmeras facetas de Hipólito estarão presentes neste estudo, sobretudo, a sua faceta maçônica. Assim, com o objetivo de analisar a sociabilidade maçônica defendida e propagada por Hipólito da Costa, tomarei como base o discurso do redator registrado não só no Correio, mas também no Diário da minha viagem para Filadélfia, na Narrativa da Perseguição e nas Cartas sobre a Framaçonaria, obras que revelam a concepção de Maçonaria adotada por Hipólito: uma sociedade de homens virtuosos, cujo fim é fazer bem às famílias consternadas.

Dynamics of in-plane arch rocking: An energy approach

This study employs an analytical model to describe the rocking response of a masonry arch to in-plane seismic loading. Through evaluation of the rate of energy input to the system, the model reveals the ground motions that cause maximum rocking amplification. An experimental investigation of small-scale masonry arches subjected to past earthquake time histories is used to evaluate the analytical model and to explore arch rocking behaviour. The results demonstrate that rocking amplification can occur, but is highly sensitive to slight variations in the ground motion. Thus, the accuracy to which the arch response can be predicted is brought into perspective. The concept that the primary impulse of an expected ground motion is fundamentally important in predicting arch collapse is evaluated in light of the developed energy approach. Finally, a statistical method is proposed for predicting the probability of arch collapse during seismic loading.

A method and tool for 'cradle to grave' embodied carbon and energy impacts of UK buildings in compliance with the new TC350 standards

As operational impacts from buildings are reduced, embodied impacts are increasing. However, the latter are seldom calculated in the UK; when they are, they tend to be calculated after the building has been constructed, or are underestimated by considering only the initial materials stage. In 2010, the UK Government recommended that a standard methodology for calculating embodied impacts of buildings be developed for early stage design decisions. This was followed in 2011-12 by the publication of the European TC350 standards defining the 'cradle to grave' impact of buildings and products through a process Life Cycle Analysis. This paper describes a new whole life embodied carbon and energy of buildings (ECEB) tool, designed as a usable empirical-based approach for early stage design decisions for UK buildings. The tool complies where possible with the TC350 standards. Initial results for a simple masonry construction dwelling are given in terms of the percentage contribution of each life cycle stage. The main difficulty in obtaining these results is found to be the lack of data, and the paper suggests that the construction and manufacturing industries now have a responsibility to develop new data in order to support this task. © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Mechanical and durability properties of concretes containing recycled lime powder and recycled aggregates

According to a recent report by the European Commission, within the European Union, the construction and demolition wastes come to at least 450 million tons per year. Roughly 75% of the waste is disposed to landfill, despite its major recycling potential. The bulk constituents of demolition debris are concrete (50-55%) and masonry (30-40%) with only small percentages of other materials such as metals, glass and timber. In Cyprus, at present, recycling of waste materials is practically inexistent and almost the entire demolition waste products are disposed in landfill sites, with all possible economic, technical and environmental impacts. This research paper presents the evaluation and the effective reuse of waste construction materials, such as recycled lime powder (RLP) and recycled concrete aggregates (RCA), disposed to landfill sites in Cyprus, due to the lack of a lucid recycling policy and knowledge. Results show that both RLP and RCA have the potential to produce good quality and robust concrete mixtures both in terms of mechanical and durability performance. © 2013 Elsevier B.V. All rights reserved.