Search results

No‐fines concrete (NFC) is an open textured cellular concrete obtained by eliminating either fines or sand from the normal concrete mix. Research in the 1950s showed this material to be capable of energy and cement savings and worthy of being seen as a material that would revolutionise the way affordable homes could be built. In today's context, it may be argued that homes built using this material suffer from fuel poverty as a result of their thermal performance characteristics. This paper seeks to discuss the performance characteristics of NFC in social housing by identifying the nature of the material and the influence of pore structure on heat loss through the fabric of the building.

Exploratory work was carried out to determine the build and performance characteristics of NFC as used in a range of social housing units. The work includes both laboratory tests and site investigations to identify the physical, thermal, visual and quality characteristics of NFC in cores taken from existing housing units in Irvine, Scotland and units cast in the lab.

The findings from the tests are used to discuss the actual characteristics of NFC and highlight the nature of pores in NFC and, their influence on heat loss through the external fabric.

Identifying the nature of pores in NFC helps provide approaches towards optimising solutions aimed at improving the thermal performance of the building.

This paper is the first to discuss the on‐site build and performance characteristics of NFC and the nature and influence of pores on the thermal performance of NFC.

The purpose of this paper is to present information on the construction technology used to build Dublin City Council’s (DCC’s) housing stock, with an emphasis on wall construction.

The methodology applied was a mix of literature review and archival research. The research was undertaken as part of PhD research exploring the energy upgrade of a housing stock.

The research uncovered details of the construction technology used in the construction of DCC’s housing stock, especially wall construction. These details disprove perceptions and assumptions made on the evolution of construction technology in Dublin and Ireland.

The research is limited in that it primarily focused on the period between 1887 to the introduction of the 1991 Building Regulations. Further research is required on both DCC’s housing stock and the Irish housing stock to identify the specific changes in construction technology.

It is hoped this research will be a foundation for further research on the evolution of house construction technology, and housing stock asset intelligence in Ireland.

This research provides information for researchers and professionals with an interest in the evolution of Irish house construction technology. This is an area which has not received significant attention in Irish built-environment research.

This paper is a continuation of “No‐fines concrete in the UK social housing stock: 50 years on” published in Issue 4 of Volume 29 of this journal. It identifies the thermal performance of existing, un‐refurbished no‐fines concrete (NFC) walls; as about 33,000 NFC homes exist in Scotland. A majority of these properties are owned by social housing providers (SHPs) and are being upgraded to current building standards. Literature identifies the thermal performance (U‐value) of NFC walls ranging from 1.1 W/m²K to 2.0 W/m²K depending on the build‐up of the structure. The homes are classified as “hard to treat” and, as a result, the occupants experience “fuel poverty”. SHPs currently adopt a range of measures to refurbish NFC properties and adopt a broad brush approach, refurbishing a range of non‐traditional (NT) constructed dwellings under similar refurbishment packages. The purpose of this paper is to call for a re‐think in terms of such refurbishment approaches when seeking to improve the thermal performance of NFC properties.

Various cores were extracted from NFC homes in the West of Scotland to explore the heterogeneity of NFC construction. To measure the thermal performance of existing NFC homes, in situ u‐value calculations were undertaken through case studies and fieldwork.

The findings of this research highlight the heterogeneity of NFC construction. The paper discusses the different approaches adopted by SHPs and identifies the variations between individual NFC elements resulting from workmanship and build issues.

The findings expose the heterogeneity of individual NFC elements and further suggest that any decision to adopt a refurbishment approach must be based on a detailed consideration of the existing characteristics of the property including location and orientation of the property.

This paper is the first to discuss the in situ u‐values of NFC properties in the last 20 years. It will be of interest to SHPs planning to refurbish such properties.

Porous concrete is a mixture of open‐graded coarse aggregate, water and cement. It is also occasionally referred to as no‐fines concrete or pervious concrete. Due to its high infiltration capacity, it is viewed as an environmentally sustainable paving material for use in urban drainage systems since it can lead to reduced flooding and to the possibilities of stormwater harvesting and reuse. However, the high porosity is due in the main part to the lack of fine aggregate particles used in the manufacture of porous concrete. The purpose of this paper is to present a numerical method to understand more fully the structural properties of porous concrete. This method will provide a useful tool for engineers to design with confidence higher strength porous concrete systems.

In the method, porous concrete is modelled using a discrete element method (DEM). The mechanical behaviour of a porous concrete sample subjected to compressive and tensile forces is estimated using two‐dimensional Particle Flow Code (PFC2D).

Three numerical examples are given to verify the model. A comprehensive set of micro‐parameters particularly suitable for porous concrete is proposed. The accuracy and effectiveness of simulation are confirmed by comparison with experimental results and empirical equations.

The experimental investigations for porous concrete described in this paper have been designed and conducted by the authors. In addition, the type of two dimensional PFC analysis presented has rarely been used to model porous concrete strength characteristics and from the results presented in this paper, this analysis technique has good potential for predicting its mechanical properties.

This study aims to use porous concrete and mineral adsorbents (additives) for reducing the quantity and improving the quality of urban runoff.

The effects of adding mineral adsorbents and fine grains to porous concrete is tested for increasing its performance in improving the quality of urban runoff. Two levels of sand (10 and 20 per cent) and 5, 10 and 15 per cent of zeolite, perlite, LECA and pumice were added to the porous concrete. Unconfined compressive strength, hydraulic conductivity (permeability) and porosity of the porous concrete specimens were measured. Some of the best specimens were selected for testing the improvement of runoff quality. A rainfall simulator was designed and the quality of the runoff was investigated for changes in electrical conductivity (EC), total suspended solids (TSS), total dissolved solids (TDS) and chemical oxygen demand (COD).

The results of this study showed that compressive strength of the porous concrete was increased by adding fine grains to the concrete mixture. Fine grains decreased the permeability and porosity of the samples. Zeolite had the highest compressive strength. Samples having pumice own maximum permeability. Samples which had perlite, had the least compressive strength and permeability. Because of the fast flow of runoff water in the porous slab and its low thickness, sufficient time was not provided for effective functioning of the additives, and the removal percentage of the pollution parameters was low.

Porous concrete can ameliorate both quantity and quality of the urban runoff.

During September 1986, several local authorities in the Merseyside area were contacted and asked if it would be possible to carry out a survey and investigation of council dwellings which had suffered from condensation and mould growth, and which had also had remedial measures carried out. An invitation was received from West Lancashire District Council to carry out a survey at the Tanhouse 4 site in Skelmersdale. Several owner‐occupied ex‐council dwellings on the same estate were also to take part.

To summarise research undertaken by the BRE into the identification and condition assessment, of non‐traditional housing. During the 1980s, defects were discovered in the design and construction of a number of house types designed and built before 1960 and these were subsequently designated as inherently defective under the Housing Defects legislation.

The research involved several years of investigation during which many different types of pre‐cast concrete, in situ‐concrete, steel‐ and timber‐framed housing systems were investigated. This research has culminated in the publication of a major new book and CDROM.

Overall the majority of non‐traditional dwellings have provided levels of performance not very different from many traditionally built dwellings of the same age. However, there are inherent defects with several systems. Some dwellings may be beyond economic repair.

The surveyor needs to be aware of the system of non‐traditional dwelling under inspection and to understand the likely defects and necessary remedial work.

This research will inform surveyors and home inspectors of the identification of non‐traditional dwellings, modes of failure of various systems, whether economic repair is possible and what remedial action should be proposed.

This paper makes a comparison between the electrical properties of cement grout with and without monofilament polypropylene fibre additions. The findings show a small, but significant difference between the electrolytic transport properties of cement grout with monofilament polypropylene fibre additions when compared to grout without fibre additions. The grout with fibre additions suggests a reduced probability of water and ion transmission, due to higher measured resistivity, which will result in enhanced durability and lower life cycle costs. Durability of reinforced concrete structures, is known to be closely linked to the water permeability of the concrete matrix. This potential trend for enhanced durability can be added to the other benefits of using monofilament polypropylene fibre in concrete, such as low absorption, freeze/thaw resistance, fire resistance and micro reinforcement.

Discusses the process of overcladding, assessing economic and social factors, and the various physical problems it can remedy. Explores the desirable features of overcladding, highlighting water resistance, K value, fire resistance, high vapour permeability, dimensional stability, impact resistance, adjustability, low weight, ease of cleaning and maintenance, experienced installers and good appearance. Outlines the various factors for success, and stresses the necessity of creating a breathing fabric to alleviate condensation problems.