Using the accelerated Brazilian concrete prism test (ABCPT) to evaluate alkali aggregate reaction (AAR)

Abstract

There are many test methods used in the laboratory to detect potential alkali-aggregate reactions (AAR). However, up to now, there is no consensus if they are reliable and efficient. This work presents the development of a new and accelerated concrete prism test called ABCPT (accelerate Brazilian concrete prism test) as an attempt to create a reliable and fast test that can analyze and classify the potential reactivity of aggregates in the laboratory. For this research, six aggregates from different lithotypes were used. The methods CPT, ACPT and ABCPT were carried out with all the aggregates and a comparative analysis among all tests was performed. ABCPT seems to have a great potential to analyze and classify aggregates in the laboratory, although it needs further testing with other lithotypes to be confirmed as feasible.Keywords: alkali-aggregate reaction, test methods, concrete prism test (CPT), accelerated Brazilian concrete prism test (ABCPT).Existem muitos métodos de ensaio de laboratório utilizados na prevenção da reação álcali-agregado, entretanto, até o momento não existe consenso no que tange confiabilidade e eficiência destes. Este trabalho apresenta a tentativa de desenvolvimento de um novo método de ensaio acelerado denominado ABCPT (método acelerado brasileiro de prismas de concreto), com o intuito de que este possa, de maneira rápida e confiável, analisar e classificar agregados mediante a sua potencial reatividade em laboratório. Para o desenvolvimento desta pesquisa, foram utilizados seis litotipos diferentes de agregados. Os métodos CPT (método de prismas de concreto), ACPT (método acelerado de prismas de concreto) e ABCPT foram realizados com todos os agregados e após, uma análise comparativa foi realizada. Os resultados indicam que o ABCPT demonstra grande potencial para utilização na análise e classificação de agregados em obras correntes de engenharia. No entanto, para a sua real comprovação, torna-se muito importante a realização do ensaio com um maior número de amostras de diferentes litotipos.Palavras-chave: reação álcali-agregado, métodos de ensaio, método de prismas de concreto (CPT), método acelerado brasileiro de prismas de concreto (ABCPT). Using the accelerated Brazilian concrete prism test (ABCPT) to evaluate alkali aggregate reaction (AAR)Uso do método acelerado brasileiro de prismas de concreto (ABCPT) para avaliação da reação álcali-agregado (RAA) Abstract Resumo

Alkali–Silica Reactions: Literature Review on the Influence of Moisture and Temperature and the Knowledge Gap

“… ASR-induced ultimate expansion at different temperatures reported by several authors [ 71 , 77 , 82 , 88 , 90 , 91 , 92 , 93 ]. …”

“…The differences in the mobility/dissolution parameters and structure of the gels can influence the kinetics of the reaction, leading to a possible rise in the expansion rate by 1.7 times when the temperature is increased from 38 • C to 50 • C [82]. As a result, several laboratory performance tests were conducted at high temperatures to increase the rate of expansion and reduce their duration [90][91][92]. Table 2 comprises a database of several ASR tests that have been conducted at different temperatures, highlighting the uniqueness of each test.…”

Effects of alkali-silica reaction on mechanical behavior of four-pile caps

“…The literature includes several experimental studies on the alkali-aggregate reaction, namely Gomes [1], for example, who studied experiments on the structural recovery of foundation caps; Sanchez et al [2] addressed a new method called the accelerated Brazilian concrete prism test (ABCPT), in which the results indicated that that test had great potential to detect aggregate reactivity in current engineering projects; Sanchez et al [3], who presented test results from the Stiffness Damage Test (SDT) and the microscopic evaluation of the Damage Rating Index (DRI) to assess the level of damage to the AAR-affected concrete. However, there are only a few numerical studies on expressions of such reactions on foundation caps.…”