The Versatility of Concrete

Taking the versatility of concrete to mean its ‘adaptability to a wide variety of purposes’, this paper looks at what it is about concrete that lends itself to varied uses and how those many uses reflect concrete’s character

By Edwin A.R. Trout, manager of Information Services, The Concrete Society

hat there are many and varied uses for concrete and steel in the British Empire, it is progress of concrete in the UK: It is 30 years concrete is indicated by the ‘Little book of hoped that its pages will not only be of interest since reinforced concrete was first used in this Tconcrete’ 1, a marketing document issued country, and during that comparatively brief and of use to those already directly and by British Precast around four years ago, indirectly concerned with the subject under space of time it has steadily advanced to a which sets out 100 advantages gained by using review, but that by their advocacy of what is leading position among the materials of concrete. In the introduction its compiler writes practical and economical in civil and . …For nearly every class of of concrete: It is the most commonly used architectural engineering, they will also compel engineering structure, it has become the in the world; yet we take what the attention of those who may still be holding standard form of construction and the revision it does for granted – too often this means that aloof from the application of the modern of the Building Acts and bye-laws which is now much of what concrete can offer is overlooked . methods of construction dealt with. In fact, this in progress, will render it even more economical Concrete’s undoubted versatility has been a journal should stimulate interest in all and increase its scope for architectural work. gift to those responsible for its marketing appertaining to concrete and steel, and In the near future it will undoubtedly be used over the years. As the author of this paper works especially in questions relating to their to as great an extent in this country as on the for the Concrete Society, running an information application economically, rapidly and safely 2. Continent and in America. service that started out as the library of the The key phrase above is: ‘economically, Reinforced concrete has been used for the Cement & Concrete Association, it begins by rapidly and safely’. These were attributes that construction of buildings of every possible looking at some examples of how concrete’s concrete was seen to offer the construction type, and future publications in this series will versatility has been promoted over the years by industry. From the very first issue, in a column contain illustrations and descriptions of – these organizations. headed ‘New Uses for Concrete’, the journal churches, cinemas, concert halls, dwelling Concrete & Constructional Engineering , the drew attention to how concrete could be, and houses, factories, flats, garages, hospitals, forerunner of the Concrete Society’s Concrete was being, used around the world. hotels, offices, schools, theatres, warehouses magazine, was launched in 1906. Its editor, the In 1933 the Concrete Society’s immediate etc 3. energetic Edwin Sachs, was predecessor was established; the Reinforced Only two years later, in 1935, the Cement & determined to win new markets for concrete: Concrete Association quickly issued the first in Concrete Association (C&CA) was founded As a pioneer journal on the application of a series of Reviews. No.1 reflected on the and its promotional magazine, Concrete ‰

December 2011 www.Agg-Net.com 11 as in the factory, and that opens preoccupation. Portland’s superiority over up many more options for Roman cement, for instance, was demonstrated construction – the method of in a series of published tests by John Grant in placing, size of element possible, the 1860s. This adhesive quality permits the flexibility of form, adjustability of continuous pours that characterize concrete construction programme – though construction and allow it to combine with it does leave concrete vulnerable other materials. The development of cements to charges of inconsistency and has constantly progressed and today there are difficulties in quality control. high-strength specialist compounds, such as There is also the composition of Densit’s CRC, which, since the European concrete. To use a well-worn Concrete Building Project at Cardington, has analogy, concrete technology is acted as the ‘glue’ for bonding precast elements. similar to cake-baking – a wide Plasticity Fig.1. A sprayed-concrete railway wagon variety of results can be achieved by mixing a small number of basic ingredients The consistence or workability of concrete in its Quarterly , was launched after the War in July in varying proportions (eg flour, fat and sugar), plastic state can lie at any point on a continuum 1947. The first issue alone featured dams and choosing a binder (eg eggs or milk), and from a flowable slurry to a stiff mix before coastal defences; bridges, railways, motorways combining extras for special effects (eg fruit, reaching solidity. Its plasticity allows the and bus garages; collieries and power stations; spice, chocolate, essence or food colouring). A concrete not only to be moulded, but also affects water treatment and sewage works; farms; and sticky mixture is usually moulded to the the method of production and placement. A stiff houses and flats. Subsequent issues included: required shape and a change of state takes concrete can be simply tipped down into an stadia and swimming pools; churches and place in the presence of heat. The resulting excavation, but not if the destination is remote, prisons; docks, water towers and silos, among material can then be embellished with a range inaccessible or above the point of discharge many others. of surface treatments if desired (icing, chopped from the mixer. The workability of concrete has The sheer variety of building types and nuts etc). Victoria sandwich is conspicuously allowed for increasing mechanical means of construction sectors is enormous, and far different from Dundee loaf, but the two are placement, eg pumping or spraying. wider than those for which competitive identifiably cakes. The cement gun, as it was originally known, structural materials are used. Each rival This mixing of varying constituent materials used for spraying concrete, was developed in material has its natural uses, where it is affects its character and allows the basics of America in 1911 where it had found a niche role employed to optimum effect, but in structural concrete to be adapted to innumerable in, among other things, constructing concrete terms the compass of most is relatively limited. purposes. Some of these characteristics vary bodies for railway wagons immediately after the Where else would asphalt be used except for little and are common to most concretes. The First World War (fig. 1). Sprayed concrete was paving? Glass is used for windows in all classes next section looks at some of these basic introduced to Britain in 1919. of buildings and as cladding in commercial attributes, and their influence on early As concrete mixed for casting on site has a buildings, and though there have been recent applications, before moving on to look at how limited period in which to be discharged, the moves to use glass structurally, eg in bridges, concrete has specialized in different directions mechanics of production are such that concrete this remains highly exceptional. Clay is widely over the years. can be mixed at a distance, in transit, or on site, used for roofing and wall tiles, and in this in a large static batching plant or in a country is dominant in masonry, particularly in Some inherent wheelbarrow. Mobile mixing of concrete has a the residential sector. Timber is used extensively characteristics of plain long history from the Victorian horse-drawn for floors, partitions and cladding, with an mixer and inter-War concrete train, to the ready- increasing role in frames, most noticeably in concrete mixed concrete industry of today. housing and temporary buildings. Steel is, Hydraulicity Formlessness or fluidity of form perhaps, the closest comparable, arising, like Cement is concrete’s active binding constituent, One of the defining characteristics of concrete concrete, in the later 19th century and and the principal cement of the past 170 years is the lack of its own form. It takes up the shape competing for the attention of engineers and – what commentators such as Winn and Howe into which it is moulded while in its plastic state. . It dominates in frames for multi- in the early years of the 20th century have called It is cast – pre- or in situ – into a mould or storey buildings; is widely used for floors, the ‘Concrete Age’ – is Portland cement. formwork, or a void to be filled. Whereas roofing and cladding for commercial and However, there have been other cements cement found its initial uses in mortar or industrial buildings; and is extensively used for during that period and certainly there are stucco applied to brickwork, early concrete took bridges, silos, gantries etc. many cementitious materials on the market the form left for it in the ground as foundations, What is it about concrete that allows it to today, but the development of an artificial or as masonry backing or infill for civil compete in so many markets and to be used in hydraulic cement capable of industrial engineering projects. Volume-produced 40-ton so many ways? What are the characteristics – production was the aim of cement pioneers blocks for Admiralty breakwaters constituted both those inherent to the material and those from Smeaton to Aspdin. The hydraulicity of a an early example of precast manufacture, as did imparted by decades of development – that have proportioned mixture of chalk and mud was the work of the London house builder W.H. led to such a wide variety of uses over the years? cement’s key attribute: when hydrated it Lascelles, but shuttering for in-situ building and Perhaps most fundamental is its plasticity hardened and strengthened, rather than slaked bridge construction also developed in the final and the variability of its constituents. Unlike any or dispersed. Concrete made with Portland three decades of the 19th century. Perhaps the of its rivals, it can be formed into its final shape cement could be placed effectively in water. It most ubiquitous early application of concrete’s on site or at the factory. What other material can should be no surprise, therefore, that early ‘mouldability’ was in architectural mouldings: offer this flexibility? Plastics, iron and steel, applications included harbour works at Dover cast stone door and window dressings, string- glass, and clay products are all produced in the and Cherbourg (1848–53), then at Le Havre, courses, coping stones etc (fig. 2). factory or foundry, in the glass-house or brick Brest and La Rochelle. At one end of the spectrum, concrete is often kiln. Manufactured products are brought to site used simply for filling voids that are out of sight and assembled as components of the building. Adhesion in operations such as mine stabilization, an Asphalt, conversely, is laid only in situ. Timber, The power to stick is also a function of the example of which, at Comb Down in Bath, has perhaps, lends itself both to prefabrication and cement content. During the formative years of received publicity lately in the magazine to cutting or carving on site. But concrete alone the British cement industry, the comparative . On a smaller scale, can be moulded into its final form on site as well testing of different types of cement was a

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the Great Exhibition in 1851, where designed to be impregnable against aerial several concrete products were bombardment. It was captured by Allied troops tested to destruction. before it had become operational. In the decades following the Armament and protection have since Exhibition concrete was used in its continued, as always, to leapfrog each other in plain or mass form, for docks, development. During the Gulf War the GBU-028 foundations, dams etc, applications ‘Bunker Buster’ bomb was developed that that required the bearing of would penetrate up to 7m of concrete. Now the compressive loads. Americans have developed a form of very high-strength, steel-fibre-reinforced concrete Weight with the intention of replacing hardened steel Concrete is inherently heavy, plate armour. With a tensile strength twice that consisting largely of aggregate of conventional concrete, it will resist most derived from stone – be it crushed forms of ammunition. On a more modest rock or gravel. Often this is a scale, Phil Purnell at Leeds University has desirable quality in providing solidity recently proposed a development of and resistance to movement, eg in cementitious composite discs to be used in early coastal defences. Concrete bullet-proof vest manufacture. has been used consciously as a weight, often a counterweight, but Massiveness the greater challenge has been to Concrete’s weight, strength and robustness add find ways of lessening the weight of to the monolithic nature of the material. In its concrete, of developing a lightweight early applications concrete was often a ‘massive’ aggregate that does not necessitate material, most characteristically used in the sacrifice of strength. This will be infrastructure projects and on a big, occasionally looked at later in this paper. monumental scale. Fig. 2. Ornate concrete mouldings on a building in Hollywood Looking backwards, the first issue of Toughness and impact- Concrete & Constructional Engineering in and a less familiar instance of void filling, is resistance 1906 traced progress from dock walls to concrete’s former role in ‘tree dentistry’, where In its resistance against rough foundations and reservoirs, from ‘earlier for years concrete was used in arboreal circles treatment, impact and physical damage, massive works into building and into bridges for plugging hollow trunks and repairing concrete has had few challenges more severe especially’. The railways had become damage to branches. than in its military use as a defence against ambassadors for concrete, most notably the At the other end of the spectrum is the use projectiles and explosive munitions: bullet-proof North British Railway on the line from Fort of concrete for sculpture, where shape is all- concrete, bomb-proof concrete and missile- William to Mallaig. Along this route there were important and structure, for the most part, is proof concrete. There are many early and retaining walls, platforms and station buildings, not the prime consideration. James Aspdin’s recent examples. bridges and viaducts – especially the Glenfinnan ‘Prophet Samuel’ is an early illustration dating During the late 19th and early 20th centuries Viaduct, the acme of contemporary construction from the 1840s. It served little purpose other massive systems of fortification were built in in mass concrete. About the same time the than to demonstrate the material, and the Europe: Dutch forts along the German border, newly combined Associated Portland Cement illustrative nature of concrete sculpture has bunkers in the trench systems of the Western Manufacturers (later Blue Circle Industries) been exploited by the promotional literature ever Front, the Siegfried Line, the Maginot Line. issued a glossy promotional book entitled since. Incidentally, the world’s tallest free- Britain fortified its south-coast naval A Great British Industry . It highlighted the major standing concrete statue is in Stalingrad: a installations and imperial stations such as Hong projects in which the company’s products had propagandist celebration of the Soviet Union’s Kong and Singapore. Indeed, much of the featured over the previous years. Perhaps victory over the German army in 1942. A pioneering research into cement and concrete predictably they comprise big symbol of the ‘motherland’, this sword-wielding in this country was conduced by the military and structures, as shown in table 1. female figure stands over 80m tall – the naval establishments at Chatham. equivalent of a 30-storey building. As the Second World War approached the Table 1 threat from mass bombing was recognized and Date Project Compressive strength the British Government planned for bomb ‘Concrete is strong in compression but weak in shelters. Concrete Publications Ltd issued 1855 Tilbury Docks tension’. How often is that heard? Yet this is, Trench, surface, bomb-proof and other air-raid 1895 Southampton Graving Dock without doubt, one of the fundamental shelters in 1939, written the young Ove Arup. 1879-1881 New Eddystone Lighthouse characteristics of concrete. Why else would As the war unfolded pillboxes, anti-tank 1883-1887 The Tay Bridge concrete have so quickly found a niche as the defences and gun emplacements followed. 1892-1897 Blackwall Tunnel foundation material par excellence and become On 23 March 1942 Hitler ordered the 1881-1888 Vyrnwy Dam so closely associated with the requirements of construction of the Atlantic Wall, a huge 1898-1902 Assouan Dam civil engineering? As E. Dobson said as early as undertaking of fortification from northern 1904 Frankley Reservoir, Birmingham 1850: ‘Concrete is a valuable material when Norway to the Spanish border, 10% of the and corporation waterworks applied in a proper manner, viz. in underground concrete for which was allocated to fortifying works where it is confined on all sides, and is, the Channel Islands. Towards the end of the war Durability consequently, subjected to little cross strain’4. the German Wehrmacht prepared to conduct Durability is taken to mean resistance to The strength conferred on concrete by the an air campaign against London by launching internal and external deteriorative processes, choice of cement was a matter of constant V2 rockets from a secret bombproof bunker in to long-term degradation. This aspect of experimentation in the 19th century, and northern France. In Calais, a colossal dome, concrete is of ongoing interest and there is an Portland cement’s success over rivals such as 72m in diameter and seven storeys tall, was immense amount of literature on it, but for the ‘Roman’ and ‘British’ cement was largely erected to construct and house the rockets prior purposes of this article it is suffice to say that down to strength. Concrete’s strength was to launch. Some 55,000 tonnes of heavily a measure of concrete’s durability is the state celebrated in the building materials section of reinforced concrete were used, 5m thick, and of repair of early concrete structures. The ‰

December 2011 www.Agg-Net.com 13 attention was its fire-resistant quality (fig. 3). After a vogue for cast iron floors, the first genuinely fire-resisting floor was patented by Dr Henry Hawes Fox in 1833. It contained a lime concrete. Other designs followed and by the 1880s so-called ‘clinker concrete’ was widely used in conjunction with iron joists as a means of constructing fire-resistant floors in commercial and public buildings. A series of disastrous fires in London theatres during the early 1890s motivated the young architect and architectural historian Fig. 3. A graphic depiction of concrete’s fire- resistant properties Edwin Sachs to devote his professional energies to improving theatre design and seeking the Pantheon of ancient Rome is the obvious best methods of fire prevention. He established example, even the great pyramids of Egypt the British Fire Prevention Committee, according to some theories, but this paper takes forerunner of the Fire Research Station (now a look at a form of concrete more akin to part of BRE) and organized the International Fire present-day Portland cement concretes and Prevention Congress in 1903. Significantly, looks at its long-term performance in highly after a series of BFPC investigations, he came aggressive, marine conditions. The concrete to the conclusion that the new material then Fig. 4. Tensile strength: concrete tower at the ships built at the end of the First World War form being introduced to the British market, Cologne Werkbund exhibition (1914) a readily-identifiable corpus of examples of reinforced concrete, would be the best for concrete structures subject to torsional forces constructing fire-resistant buildings. It was this systems of reinforced concrete were waiting to at sea, impact from collision and the effects of aspect of concrete’s performance that enthused be realized. corrosion from saltwater. Sachs in its favour and prompted him to found As the RCA’s Review of September 1936 the journal Concrete & Constructional Tensile strength pointed out, ‘it would be difficult to devise a Engineering in 1906 and the Concrete Institute The juxtaposing of concrete’s resistance to severer or practical test of the durability of a (later the Institute of Structural Engineers) in compression with steel’s resistance to tensile structural material than to build seagoing 1908. stresses was fundamental to reinforced ships with it, and put them to work under such In the 1930s the Reinforced Concrete concrete’s success, and one of the earliest conditions as have been encountered by the Association was quick to promote ‘resistance British writers on reinforced concrete, Lt Col J. Creteboom , Cretestem , Askelad and Polias’ . to fire’, featuring the topic in its fifth promotional Winn RE, was quick to point out the The former, after 15 years’ service in the ice- Review and pointing to an early example of an opportunities in 1906: ‘the introduction of steel bound Baltic, though no longer of attractive entire building subject to fire – the Edison to enhance tensile strength extended concrete’s appearance, was described as ‘perfectly sound’. Phonograph Works in New Jersey. On 19 employment into new elements: floors, beams, In 1922 a salvage survey of Polias , sunk two December 1914, this factory, packed with arches, piles, walls, partitions, pipes, aqueducts, years earlier, claimed ‘the test is one showing gramophones, records, films and projectors bridges of large spans, tall chimneys, very clearly the high resistance of reinforced made of highly combustible wax and celluloid, lighthouses. …Immense warehouses, depots, concrete to exceptionally severe shocks and succumbed to a conflagration of great intensity. cold storage sheds, drill halls, and factories stresses’, contrasting the ship’s condition with An international investigation followed, have been built…entirely of this reinforced a steel or timber vessel which ‘would not comparing the traditional brick structures concrete. …It would be impossible in the space have survived for more than three months in the with the new reinforced concrete. Whereas the of a short article to refer to all the varied uses 5 same situation’. The Review was ‘written with traditional buildings were destroyed, the to which reinforced concrete has been applied’. the object of demonstrating the durability of concrete structures were returned to Francis Onderdonk, an advocate of reinforced concrete as a structural material’; manufacturing within 30 days. architectural concrete writing in the 1920s, a more scientific and systematic survey, entitled Fire resistance remains one of concrete’s looked back to the origins of reinforcement: ‘In ‘Concrete in the oceans’, was conducted by the claims, though there has been some dispute 1878 Monier claimed for reinforced concrete C&CA and partner organizations in the 1970s with the promoters of steel in recent times over that, as far as form is concerned, it has no limits. and 80s. the nature of such comparisons. Reinforced concrete has conquered the third 6 Today, it is well known that durability is a dimension’. more complex issue than was considered to be Characteristics of concrete He went on to write: ‘Reinforced concrete the case in the 1930s. For example, in recent after the advent of combines the advantages of steel, stone, and years bridges with a nominal design life of 100 wood, eliminating many of the disadvantages years have been examined for the deleterious reinforcement of each. The reinforcing bars, bendable and not effects of ASR and thaumasite, but there are The urgency of finding a suitably fire-resistant limited as to length and slenderness, can many examples of 19th century bridges extant, building material in the 1890s coincided with the follow the most complex lines and curves and such as the very early Flixton Bridge of 1870. scientific development of reinforced concrete, give the surrounding concrete an indestructible The Hoover Dam was built in the 1930s, largely by French and German-speaking backbone. Being plastic when placed, concrete supposedly with a design life of 2,000 years, pioneers. With the advent of commercially can adopt any conceivable form. Practically though there will be a long wait to see if it promoted reinforcement in Britain from 1897, unlimited length, slenderness, and intricacy are outlasts the Pantheon’s present-day the nature of concrete, and the range of its combined with strength and durability in achievement. Austrian inventor Ludwig corresponding applications, underwent a huge concrete’. Hatschek was even more confident in the change. An enormous number of new Purposely to illustrate concrete’s strength, durability of fibre cement when, in 1900, he possibilities were opened up for exploitation by and in a gesture reminiscent of the Great named his new product Eternit, from the Latin the new material, enthusiastically promoted by Exhibition of 1851, the organizers of the Cologne ‘aeternus’, or everlasting. the Fire Prevention Committee, the RIBA and Werkbund exhibition in 1914 had a structure the newly established Concrete Institute. erected where a tower surmounted three Fire resistance Looking forward at the dawn of the ‘Concrete nearly horizontal supports over a void below One of concrete’s early claims to special Age’, the prospects for the recently patented (fig. 4).

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before the Great War. It reached its apogee in the work of Nervi in Italy and Candela in Mexico. A dome roof was designed in 1917 at the London offices of Christiani & Neilsen, but in this country shell roofs generally had to wait for the era of pre-stressing that boomed in the 20 years or so from 1945. In the case of church-building, where elegance and visual appeal have long been valued, the contrast was marked by, for example, the architect Auguste Perret who introduced concrete tracery in the 1920s to create interiors of lightness and delicacy, complementing his soaring church towers (fig. 6). Architectural use New structural forms allowed a new aesthetic, and although architects in this country did not hasten to explore concrete’s potential as a new medium, by the 1920s the work of Sir Maxwell Ayton and Owen Williams was prompting interest. In 1927 Bennett & Yerbury’s Fig. 5. Eienstein’s Tower at Potsdam in 1920s photographic survey ‘Architectural design in Germany concrete’ promoted the idea of a new concrete Fig. 6. Slenderness: Le Raincy Curch, by Auguste The later development of pre-stressing architecture, where form reflected purpose, Perret accentuated concrete’s performance in tension, construction was monolithic, and wide spans, making longer-span roofs and bridges possible, cantilevers, slender columns and continuity of he espoused, perhaps most notably at the and more recently still, the makers of the support throughout the height of the building Shrine of the Sacred Heart in Washington, DC. proprietary material Ductal have imparted was possible. Concrete may naturally be a shade of grey, greater tensile properties to the concrete A year later, Francis Onderdonk’s pedagogic and this fact has left a negative and perhaps itself. book, Ferro-Concrete Style , more emphatically indelible impression on public perceptions of advocated a style of architecture specific to the material. It certainly need not be that way, Monolithicity concrete, pointing to its spontaneous, if uneven, however, as the producers of pigments have The monolithic nature of the material allowed emergence in Europe and America. He quoted endeavoured to prove and the vibrant work of a new structural continuity of form. Elements Dr A. Willnow’s claim that ‘Ferro-concrete, in artists such as Carole Vincent and David could blend seamlessly, and whereas the contrast to steel, is capable of creating an Undery, captured on the pages of Concrete structural use of steel and timber for spans architecture’. A sweeping claim indeed, but Quarterly, has shown in recent years. depended on a framework of beams, girders, looking at the impact of new materials, one that struts and rafters, reinforced concrete was able Bennett had also made. Similarly, R.J.M. Lightness to incorporate the slab itself as a structural Sutherland has since suggested that ‘concrete Combating the innate heaviness of concrete was element. In buildings, flat-slab construction was ideally suited to the post-war fashion for a challenge that confronted the promoters of developed from C.A.P. Turner’s mushroom-head ‘functional’ architecture. It could even be concrete in the early years of the 20th century. system first used in 1904, and in bridges, argued that the fashion was largely created by The American Stephen J. Hayde is known as the integral deck slabs or ‘beamless decks’ were the material’. 7 The symbiosis of steel and father of lightweight concrete, having developed designed by R. Maillart from 1910. concrete allowed reinforced concrete the first commercially viable manufactured Again contrasting with steel, concrete could construction to take on new structural forms lightweight aggregate. A brick-maker by trade, adopt curved organic shapes that were and, combined with concrete’s freedom of and a contractor, Hayde endeavoured to find a otherwise achieved in the vertical plane by brick shape, allowed the development of a distinctive use for the waste ‘bloaters’ from his brickworks or on a small scale by mud or plaster new architecture. and in 1897 considered crushing them for construction. Concrete could appear to flow in Onderdonk quotes a florid statement by the incorporation in concrete. Bloaters were bricks three dimensions. The extraordinary Einstein architect J.J. Earley: Works great and small, that had expanded excessively in the heat of the Tower at Potsdam (fig. 5) is a good example of well done with concrete, will accumulate day kiln, resulting in a structure of internal voids a building that appears to have been moulded, by day until the prestige of concrete has encapsulated by a hard ceramic matrix. They while in contemporary architecture, exponents developed power enough to sweep away all that were lightweight and when crushed had no such as Zaha Hadid have acquired reputations is in the way of its natural advancement to its plane of weakness. Years of observation and for the organic sinuousness of their designs. place in architecture and in art as the experiment led to a patent for ‘Haydite’, filed in most satisfying medium which has yet been 1914, then practical trials in Kansas City Slenderness devised . showed that a rotary kiln could be used Reinforcement allowed a slenderness of form Key to Onderdonk’s thesis was the centrality economically to produce expanded clay or and a gracefulness of construction not possible of the parabolic arch in the new structural shale aggregate. In 1917 he was confident of the with plain concrete. Massiveness was design, the use of tracery, and the possibilities technology and after America entered the increasingly replaced by slenderness, a trend of integral colour and surface texture. First World War he wrote to the newly that has continued with the development of pre- established Department of Concrete Ship stressing, higher-strength concretes and glass- Coloured and textured finishes Construction offering free use of his invention fibre reinforcement. The possibilities of colour and texture were for the duration. Thus the first application of Such slenderness found expression in the explored by Onderdonk with some enthusiasm. lightweight concrete with manufactured roofs that were now possible over ever- The plates in his book are a testament to the aggregate was in the ships of the US Emergency increasing spans. The archetypal form was the vividness of effect made possible by coloured Fleet. shell roof, a form that emerged in Germany aggregate and the various finishing treatments The first of such were the 3,000-ton ‰

December 2011 www.Agg-Net.com 15 association’s achievements in Enhanced properties of promoting a new architecture for this purpose. 8 concrete in more recent The 1930s saw a renewed times interest in water-retaining At the time of Concrete Quarterly’s launch in structures generally – reservoirs, 1947, much of the technology associated with tanks and water towers – concrete construction was recognizably mature. prompted and served by W.S. Concrete was available as plain, reinforced and Gray’s books on these subjects in pre-stressed; the concrete industry was 1931 and 1933. Revisions, later structured to provide ready-mixed concrete and known as Gray & Manning, had developed a wide range of precast products. continued to be issued by There were, of course, many further Concrete Publications Ltd and developments to come and during the following the C&CA into the 1970s. boom years the scale of concrete construction Drainage has seen the role of increased enormously. concrete diverge to serve two extremes: large-diameter pipes Admixtures Fig. 7. Diving board structure at Weston-Super-Mare lido in the to serve the supply of water, During these years the increasing use of early 1930s and porous concrete to allow chemical admixtures extended the properties controlled surface drainage. of concrete in both the fresh and hardened state. Atlantis and the 7,500-ton Selma . The Although ‘no-fines’ concrete has been used to Accelerators, plasticizers, retarders etc, allowed Department, having calculated that a large control highway run-off for many ears, the concrete to be used in ways not previously vessel would not be feasible unless the concrete widespread flooding of 2007 has given an practicable. had a compressive strength of ‘500 lb/in2’, and additional urgency to the now fashionable In recent years, the application of concrete a weight of ‘no more than 110 lb/ft3’, had ‘SUDS’ and provided a new market opportunity to new uses has been a result of a conscious embarked on similar experiments with for the concrete block paving industry. In extension of the material’s properties. Emerging expanded slate, clay and shale. Atlantis was America, a parallel interest in ‘pervious problems have prompted an exploration of the built with the output of these trials, and Selma concrete’ is receiving a lot of attention in the possibilities of concrete to find innovative with the superior Haydite. technical press at present. solutions, and concrete has been taken in With the coming of peace new uses were Acoustics some surprising directions. The motives for sought and the 1920s in America saw the such developments lie in the preoccupations of Ever since Thomas Edison’s experiments with application of lightweight concrete to high-rise the modern age: a new concern for a concrete piano, the acoustic qualities of building. Most celebrated was the extension of sustainability and environmental performance; concrete have been exploited. One of the the 14-storey Southwestern Bell Telephone Co. continuing economic advantage; and the more iconic uses of the material during building in Kansas to twice its height, compared avoidance of liabilities in a litigious industry; as wartime was the listening station on England’s with the additional eight floors possible with well as a timeless desire to seek purely south coast for which giant ‘ears’, or ‘listening normal-weight concrete. aesthetic enhancement. Since that time, Siporex and autoclaving, and mirrors’, were built of concrete. In more newer types of aggregate, have provided recent times concrete’s greater resistance to Sustainability and environmental alternative ways of achieving reductions in sound than that of rival lightweight materials responsibility weight. has been promoted for multi-storey residential construction and for compliance to Part E of the Some of these developments to enhance the Water-resistance Building Regulations. Concrete barriers to environment have been active innovations in materials or design. In the late 1990s Concrete is inherently permeable, but the protect against noise have been built along motorways and at airports, such as the researchers in Japan developed a concrete degree of porosity varies greatly and it is block containing photocatalytic compounds notable that several of its major early distinctive wavy acoustic wall at Gatwick. At the opposite end of the scale, bespoke concrete that captured and dissipated urban pollution. applications were for water-retaining In a similar vein, the coating of concrete in structures: docks, the London sewers, dams, casings for hi-fi systems have been heavily featured in the press recently. titanium oxide has been found to render and with the advent of reinforcement, tanks and concrete self-cleaning and has opened water towers. The first concrete water tower Density opportunities for low-maintenance facades. in Britain was at Mayrick Park, Bournemouth, Energy efficiency is being improved through the in 1900, to a design that set the standard for The density of concrete varies from the open textures of foamed or aerated concrete to that use of concrete floor slabs for integral heating many years to come. It was followed in 1904 by and one manufacturer has developed a paving the enormous tower at Newton-le-Willows, suitable for radiation shielding. Originally for defensive military purposes in the Cold War, slab for generating electricity through the which, for a time, was the largest in the action of repeated footfall. world. These and their numerous successors against the threat of nuclear attack, concrete with heavy natural aggregates such as barites More traditional attributes of concrete have imposed their superiority on a water supply also found a new prominence. Concrete has industry that, throughout the 19th century, had or magnetite is now often used in medical practice. always had the potential to incorporate recycled relied on sectional tanks made from cast iron material and in the 19th century crushed panels. Fibre reinforcement bricks and coke breeze were widely used as Public baths and swimming pools had In parallel to reinforced concrete, the aggregate – even oyster shells and broken emerged as a feature of urban life in the development of fibrecement in 1900, while crockery in some instances. Indeed, materials Victorian years, but it was in the 1930s – the era perhaps not strictly concrete, provided a that had been through the firing process were of the ‘lido’ – that pool construction really took cementitious alternative that had its own thought to enhance concrete’s fire-resistance off, vigorously promoted by the Amateur distinctive range of characteristics, many of properties. Since then some recycled materials Swimming Association (ASA). The material of them opposite to those of reinforced concrete. have been found to be deleterious – mundic is choice was concrete – and not just for the pool Slender, lightweight and water resistant, an obvious example – but others have been itself, but the structure of the building fibrecement products came to prominence in successfully used for many years, rising in surrounding it (fig. 7). The ASA’s seminal book the roofing and drainage markets. status from waste, to by-product, to construction on modern public baths in 1938 trumpeted the

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materials in their own right. In the 21st century pursuing the theme of this paper into recent conditions would effect changes in the material. the drive to incorporate new streams of waste times. Entrants displayed a wide range of Thus, concrete ‘Weather Tiles’ were designed from sites and industrial processes, artistic and technological ideas to various to change colour in the rain to reveal an image such as glass production, has been pursued architectural, sculptural and or inscription. Another project caused the with considerable vigour and has been widely purposes, but several themes emerged. concrete to change colour when heated. In a promoted as one of concrete’s ‘green’ Together, they provide a snapshot of progressive third, concrete street furniture would give off credentials. thinking about how this versatile material can the relaxing scent of lavender when stroked, Occasionally, this newly revived enthusiasm be applied in unexpected ways, and reflect some achieved by the micro-encapsulation of for encapsulating wastes is taken to unexpected of the underlying trends in concrete technology. perfumes. lengths. The Guardian published a piece One of the more prominent trends was the The promotional press loves these innovative, recently intriguingly referring to ‘dog poo combination of concrete with other materials, even off-beat adaptations of concrete. concrete’, in which the German architect such as glass and ceramics. Concrete has the Magazines such as OpusC (Germany), Concrete Freidrich Lentze was described as believing that ability to bond with or to encapsulate other (New Zealand), Concrete Trends (South Africa) all dog waste collected by local authorities materials homogeneously, and decorative and Betoni (Finland) are among the more should be processed as a construction material: composites such as Metzzo have been a active in this approach. Other innovations have ‘it makes a great mortar with fantastic insulating sideline of concrete for some time. Only last year also graced their pages in recent times, properties’. Lignacite’s architectural masonry block supplementing the RCA projects with eye- Concrete’s thermal mass has been containing coloured glass aggregate was catching novelties, each of which pushes the highlighted by organizations such as the featured as AJ Specificiation’s ‘material of the boundaries of what concrete can offer. Concrete Centre as one of the benefits that month’ (January 2010). Not only was the glass One RCA competitor’s method of transferring comes with concrete when seeking to regulate recycled glass, but light emitting too, thus a photographic image to a mortar-covered the internal temperature of buildings. And combining three modern trends in one. canvas reflected a continental trend for photo- the natural process of carbonation, long seen A combination of materials that has gained etching entire buildings that has been followed as an issue of durability, has been re-presented particular favour recently is concrete with by the press over the past decade. Both as an environmental advantage to partially offset cloth. The RCA shortlist in the first three years translucent and light-emitting concrete – the unavoidable production of carbon dioxide by included flock-patterned tiles, a wedding dress Litracon and Luccon – have received publicity the manufacture of Portland cement. with delicate concrete decoration, ‘Concrete well beyond their current levels of use. Canvas’ cement-impregnated emergency But this is the point. Novelties point the way Economic advantage shelters, lacy lampshades, a lattice chair and today’s innovation eventually becomes Though there is nothing new in the desire to cut inspired by gossamer veils, and panels cast in tomorrow’s tradition. New uses arise continually costs and maximize profits, the construction the shape of sheets hanging out to dry. Further as the material is adapted to meet the process might be thought of as leaner as a afield, Queen’s University has been running its challenges of the future. Concrete continues to result of changes to concrete technology. New ‘Girli Concrete’ project for some time, exploring demonstrate such versatility that its applications codes of practice, reflecting technical advances, the relationship between the traditionally appear unending. permit concrete to be designed with more ‘masculine’ qualities of concrete with the slender elements and longer unsupported softer appeal of textiles. The design practice References spans. Concrete’s naturally heavy weight has Concrete Blond is designing bespoke, fabric- 1. ‘A little book of concrete: a guide to one been reduced, not just by the traditional use of based concrete interiors, and lace-patterned hundred advantages’, British Precast, lightweight aggregates, aeration or foaming, but concrete by Caruso St John features as a Leicester, [c.2007], 115p. by void-former systems such as Bubbledeck thematic motif at the award-winning 2. SACHS, E.O.: Announcement, Concrete & and its equivalents. Systems of reusable Contemporary Arts Centre in Nottingham. Constructional Engineering , 1906, vol. 1, formwork, proprietary reinforcement, In similar vein, concrete and light have been no. 1, pp.1-6. prefabrication of elements and the use of self- explored by the RCA students with concrete 3. ‘Reinforced concrete buildings’, The Review compacting concrete for congested or lamp stands and lampshades, the integral of the Reinforced Concrete Association, inaccessible areas have all contributed to the use of fibre optics, and the application of solar 1933, no.1, pp1-4. efficiency of concrete construction, of what was power to a garden light feature. Likewise, the 4. DOBSON, E.: ‘Foundations and concrete once a labour-intensive process. latest issues of OpusC magazine have featured works’, Crosby Lockwood & Co., London, concrete lamps from studio producers. 1850. Aesthetics Other combinations with concrete have been 5. WINN, J.: ‘Advent of the concrete age’, But perhaps some of the most eye-catching even more imaginative. One installation Concrete & Constructional Engineering , recent developments in the changing nature of consisted of a series of concrete blocks 1906, vol. 1, no. 1, pp7-16. concrete have been in its aesthetic qualities. containing computers connected to an online 6. ONDERDONK F.S.: ‘The ferro-concrete These, naturally, have lent themselves to visual chat room, allowing the blocks seemingly to style’, Architectural Book Publishing, presentation and have, therefore, featured in the ‘talk’ to each other. Another depended on the New York, 1928, 265p. industry’s promotional publications to a greater incorporation of magnets to attract and repel. 7. Historic concrete, Proceedings of the degree than their use might warrant. However, In some instances the concrete replicated Institute of Civil Engineers: Structures and they do fly the flag for concrete and point to new other materials. Perhaps the most successful Buildings, Aug/Nov 1996, pp255-480. possibilities that, as haute couture does for high was an apparently steel and formica table, 8. CROSS, K.M.B.: ‘Modern public baths’, street fashion, might find their way into chipped at the edges and covered with mug London Amateur Swimming Association, commercial applications. Their initial value lies rings and coffee stains; it looked so realistically 1938, 113p. in their ability to influence the image of concrete tatty that it was almost disposed of by the 9. Awards 2002, British Cement Association, and its perception by the public. cleaners after the exhibition had been set up. Crowthorne, 2002, 13p. (and for 2003 and In 2002 the former British Cement Similarly, photographs of a pigmented concrete 2004). Association (BCA) sponsored a competition at pouffe (seemingly upholstered in burgundy the Royal College of Art. The brief was to leather) were recently published in the Acknowledgement ‘demonstrate versatility and innovation in the promotional press, illustrating just how This paper was presented at the Institute of use of cement and concrete’, with the BCA convincing concrete can be at imitating other Concrete Technology (ICT) annual technical looking for ‘a breakdown of assumptions of materials. symposium in 2010 and published in the ICT cement and concrete as a material through The nature of concrete itself was the subject Yearbook 2010-2011. It is reproduced here by 9 innovative thinking’. What better cue for of several competition entries, where external kind permission of the ICT.

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