This is a short introduction to asr for more information, see the understanding cement book ebook. Alkali silica reaction asr is the chemical reaction that occurs between alkali cations and hydroxyl ions in the pore solution of hydrated cement paste and certain reactive silica phases present in the aggregates used in concrete. Alkalisilica reaction in concrete, as seen in the scanning electron microscope an over the shoulder video looking at asr in the sem video showing details of reacting aggregate and xray microanalysis of aggregate, gel and cement paste. Role and effectiveness of mineral admixtures in relation to alkali silica reaction r n swamy. Preventing alkalisilica reaction and delayed ettringite. Alkalisilica reaction asr can cause serious expansion and cracking in concrete, resulting in major structural problems and sometimes necessitating demolition. On the basis of a different response in the mortarbar test method astm c227, swenson apparently assumed that the reaction was different from that of the classical alkalisilica reaction as described by stanton.
A book for concrete users which provides an authoritative explanation of the alkalisilica reaction. For alkalisilica reaction to occur, three conditions must be present. Topics on alkalisilica reaction development bureau. Alkaliaggregate reaction, commonly known as aar, is the chemical reaction in either. Jan 20, 2009 the use of surplus waste glass in concrete has been avoided on the grounds that it is known to undergo harmful alkali silica reaction asr. Acr was first described by swenson in a paper entitled a reactive aggregate undetected by astm tests. A critical assessment to the performance of alkalisilica reaction. We are now beginning to realise that external agents, environmental conditions and. Alkalisilica reaction in concrete containing glass. Alkali silica reaction asr asr is a chemical combining of reactive silica from the concrete aggregate with the alkali from the cement paste in the presence of moisture. Alkalisilica reaction asr designing buildings wiki share your construction industry knowledge. The alkali silica reaction in concrete swamy, r n on. Data derived from research presented at the 8th international alkaliaggregate reaction conference held in kyoto in 1989, and additional field experience of the.
Alkali silica reaction danish experience s chatterji, z. Mitigation of alkalisilica reaction in volcanic aggregate. Data derived from research presented at the 8th international alkali aggregate reaction conference held in kyoto in 1989, and additional field experience of the. Since the 1940s, considerable research has been developed to. Alkali silica reaction asr is of more concern because aggregates containing reactive silica materials are more common. Alkalisilica reaction in concrete, as seen in the scanning. This chapter provides an overview of the fundamentals of asr in concrete. Introduction to alkaliaggregate reaction in concrete a b poole. Role and effectiveness of mineral admixtures in relation to alkalisilica reaction r n swamy.
Nov 11, 2011 the alkalisilica reaction in concrete by r n swamy, 9780415512, available at book depository with free delivery worldwide. Alkalisilica reaction asr is a common cause of premature concrete deterioration, resulting in expansion and cracking of concrete elements. Alkali silica reaction danish experience s chatterji, z fordos and n thaulow. Under adverse conditions, the volume of the alkali silicate gel may gradually expand to such an extent as to cause localised. Mar 21, 2019 alkali silica reaction asr asr is a chemical combining of reactive silica from the concrete aggregate with the alkali from the cement paste in the presence of moisture. As part of a research project to develop draft specifications for glass in concrete, a major asr testing programme was undertaken to establish appropriate use of glass in concrete which avoided harmful asr. There has been an enormous amount of literature about the background theory and cases of alkali silica reaction in concrete structures after its discovery by stanton in california, usa in 1940.
Chemistry of the alkali aggregate reaction f p glasser. Alkalisilica reaction in concrete understanding cement. Alkali silica reaction gels are composed of twocomponent mixtures of alkali calciumsilicate hydrate and alkali silica sols of nearly fixed compositions. The alkalisilica reaction asr, more commonly known as concrete cancer, is a swelling reaction that occurs over time in concrete between the highly alkaline cement paste and the reactive noncrystalline silica found in many common aggregates, given sufficient moisture. Use a low alkali cement alkali silica reaction expansion under accelerated conditions and with the use of a reactive aggregate 233,234, but in the majority of cases, aam mortars show less.
A human cancer, if untreated is terminal, whereas the alkalisilica reaction and the expansion it induces, if untreated, eventually stops. The factors involved are exceedingly complex, very interdependent and highly interactive. No concreted structure or part of a concrete structure any where in the world has collapsed due to alkalisilica reaction alone. There has been an enormous amount of literature about the background theory and cases of alkalisilica reaction in concrete structures after its discovery by stanton in california, usa in 1940. In asr, aggregates containing certain forms of silica will react with alkali hydroxide in concrete to form a gel that swells as it adsorbs water from the surrounding cement paste or the environment. Cracking may be initiated by swelling of aggregate particles before copious production of gel and large expansions of cracks caused by swelling of gel occurs. The alkalisilica reaction mechanism catalysed by a soluble strong base as naoh or koh in the presence of caoh2 alkalinity buffer present in the solid.
This can cause damage to the hardened concrete in a building, and can necessitate. Alkalisilica reaction in the context of asr, the alkalis are the metal alkalis sodium and potassium. Alkali silica reaction alkali silica reaction asr in concrete is a reaction between certain silicious constituents in the aggregate and the alkali sodium and potassium hydroxide which are released during the hydration of portland cement. This distress has been mainly attrib uted to alkalisilica reaction asr and delayed ettringite formation def and. As part of a detailed study to investigate the processes and mechanism of alkali silica reaction asr, opc mortars with 50% of the aggregate. Alkali silica reactivity, better known as asr, has openly been with us since the early1940s when it was discovered in california and publicized by t. Alkali silica reaction under the influence of chloride. This volume for concrete users provides an authoritative explanation of the alkalisilica reaction asr, its effects and methods of minimizing the risk of danger in new construction.
The reactionleads to the formation of a gel which absorbs water and expandsleading to damaging expansions and cracking in the concrete. Alkali silica reaction asr can cause serious expansion and cracking in concrete, resulting in major structural problems and sometimes necessitating demolition. The use of reactive aggregates in concrete is necessary for asr to occur. Chapter 2 alkalisilica reaction guidelines for the use. The alkalisilica reaction asr, more commonly known as concrete cancer, is a swelling. The asr mechanism of reactive aggregates in concrete and its. The alkalisilica reaction in concrete swamy, r n on. Asr is a reaction between the alkali hydroxides in concrete and reactive forms of silica in the aggregate. The book is divided into two distinct but complementary parts. A book for concrete users which provides an authoritative explanation of the alkalisilica reaction asr, its effects and methods of minimizing the risk of danger in new construction. In portland cement, the reaction between the alkalies and particular siliceous rocks andor minerals which are present in some aggregates. This can cause damage to the hardened concrete in a building, and can necessitate significant remedial works or even demolition. Alkalisilica reaction article about alkalisilica reaction.
Alkali silica reaction an overview sciencedirect topics. The reaction product is a hygroscopic gel, which absorbs moisture and swells. Mitigation of alkali silica reaction in volcanic aggregate concrete using pfa and ggbs annual concrete seminar 2016 20 april 2016 ryan c. The term reactive refers to aggregates that tend to breakdown under exposure to the highly alkaline pore solution in concrete and subsequently react with the alkali hydroxides sodium and potassium to form asr gel. This volume for concrete users provides an authoritative explanation of the alkali silica reaction asr, its effects and methods of minimizing the risk of danger in new construction. The alkali silica reaction though not true is described as a concrete cancer. Alkalisilica reaction in concrete ice virtual library. Alkalisilica reaction asr is a material degradation mechanism that occurs in concrete structures. The alkalisilica reaction in concrete 1st edition r n. Alkalisilica reaction gels are composed of twocomponent mixtures of alkalicalciumsilicate hydrate and alkalisilica sols of nearly fixed compositions. Alkalisilica reaction asr is a concrete pathology due to chemical reactions involving reactive silica. Information on the development of alkali silica reaction asr damage in the uk, the chemical process of asr, and the diagnosis and assessment of expansion and cracking on concrete. Standard test method for determination of length change of. The reaction forms a gel that swells when moisture is present.
The alkali silica reaction is an unusual and unpredictable phenomenon which occurs worldwide. Alkalisilica reaction danish experience s chatterji, z. Practices to mitigate alkalisilica reaction asr affected. American society for testing and materials, annual book of astm standards, 2008, pp. Alkalisilica reaction in concrete civil engineering. Over seven decades later, occurrences of this reaction may actually be increasing, despite our vast knowledge about asr gained over these years. Alkaliaggregate reaction is a an umbrella term for two types of premature concrete deterioration. Alkaliaggregate reactions in concrete sciencedirect. The alkalisilica reaction though not true is described as a concrete cancer.
The alkalisilica reaction in concrete crc press book. Introduction to alkali aggregate reaction in concrete a b poole. The result of the reaction is a gel, which can expand and may cause microcracks in the concrete. Under certain circumstances, the formation of the gel can cause expansion and, eventually, cracking of the. These forms of deterioration encompass a chemical reaction between certain aggregate types and the host cement paste, most importantly the internal pore solution in. The alkalisilica reaction is an unusual and unpredictable phenomenon which occurs worldwide. Alkalisilica reaction asr designing buildings wiki. Mitigation of alkalisilica reaction in volcanic aggregate concrete using pfa and ggbs annual concrete seminar 2016 20 april 2016 ryan c. However, the alkalisilica reaction is a reaction between the hydroxy1 ions in the pore water of a concrete and certain forms of silica14 which occasionally occur in significant quantities in the aggregate. Concrete technology diagnosis and control of alkali. However, the alkali silica reaction is a reaction between the hydroxy1 ions in the pore water of a concrete and certain forms of silica14 which occasionally occur in significant quantities in the aggregate. Aggregates constitute about threequarter of the volume of concrete, and therefore their physical and chemical properties need to be correctly assessed before their use in concrete.
Alkali silica reaction asr is a chemical reaction between the alkalis in portland cement and certain types of silica minerals present in some aggregates. Alkalisilica reaction asr, commonly known as concrete cancer is an expansive reaction that can occur over time between aggregate constituents and alkaline hydroxides from cement. No concreted structure or part of a concrete structure any where in the world has collapsed due to alkali silica reaction alone. Chapter 2 alkalisilica reaction guidelines for the use of. Preventing alkalisilica reaction and delayed ettringite formation in new concrete introduction the state of texas has been widely impacted by materialsrelated distress in various transportation structures. In 1992 a first edition entitled the alkalisilica reaction in concrete, edited by professor narayan.
The alkalisilica reaction in concrete book depository. Chemistry of the alkaliaggregate reaction f p glasser. Alkali silica reaction in the context of asr, the alkalis are the metal alkalis sodium and potassium. Check it out to see aggressive asr attack and hear from the experts. Expansion due to alkalisilica reaction as conditioned by the grainsize of the. Alkali silica reaction in concrete, as seen in the scanning electron microscope an over the shoulder video looking at asr in the sem video showing details of reacting aggregate and xray microanalysis of aggregate, gel and cement paste. This produces an expansive gel after the cement has set, which then causes internal pressure leading to expansion and cracking of the concrete.
Use a low alkali cement book depository with free delivery worldwide. Therefore, expansion due to alkalisilica reaction will be less in concretes containing rha. In 1992 a first edition entitled the alkalisilica reaction in concrete, edited. Alkali silica reaction asr is a deleterious chemical reaction occurring in all types of structures that contain alkali reactive aggregates. Alkalisilica reaction asr is of more concern because aggregates containing reactive silica materials are more common. Alkali silica reaction under the influence of chloride based deicers a thesis presented to the graduate school of clemson university in partial fulfillment of the requirements for the degree master of science civil engineering by purvi desai august 2010 accepted by. Alkalisilica reaction asr is the chemical reaction that occurs between alkali cations and hydroxyl ions in the pore solution of hydrated cement paste and certain reactive silica phases present in the aggregates used in concrete. Information on the development of alkalisilica reaction asr damage in the uk, the chemical process of asr, and the diagnosis and assessment of expansion and cracking on concrete.
The alkalisilica reaction in concrete 1st edition, kindle edition. Alkalisilica reaction asr is a chemical reaction between the alkalis in portland cement and certain types of silica minerals present in some aggregates. It is a chemical reaction that involves the alkali ions in pore solution in cement paste and the reactive silica of concrete structure aggregates 1. It considers he advances that have been made in our understanding of this problem throughout the world. A human cancer, if untreated is terminal, whereas the alkali silica reaction and the expansion it induces, if untreated, eventually stops. The pozzolanic reaction mechanism is believed to be a process in which silicate. Alkali silica reaction is the deleterious chemical reaction between some siliceous minerals in the aggregate and the alkalinity of the concrete. National regulations for preventing alkalisilica reaction asr in concrete. Alkaliaggregate reaction portland cement association. Asr is a chemical reaction between alkali hydroxides in the pore solution of concrete and certain siliceous silicabearing rocks and minerals present in some concrete aggregates. The process and mechanism of alkali silica reaction using fused.
797 1065 1083 1513 836 1156 1128 1332 150 1448 430 1346 1130 884 913 527 1443 904 317 1408 995 1520 1087 791 39 1340 1284 1345 1385 1251 1214 1183 998 71