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A platform for research: civil engineering, architecture and urbanism
Development and characterization of expansive grouts for crack sealing.
The present paper deals with one of the main problems related to concrete structural elements, the tendency to crack as a consequence of its low tensile strength. This cracking limits the performance and durability of the concrete. Previous works by the authors showed the feasibility of using innovative expansive grouts in order to avoid or limit this cracking. These expansive grouts are based on the use of inorganic expansive agents promoting the increase of certain hydrates content. Two different agents were considered: type K (based on calcium sulfoaluminate) and type G (based on calcium oxide). The developed expansive grouts presented high penetration ability in the crack in order to prevent the ingress of aggressive agents and regain (totally or partially) the initial uncracked concrete mechanical properties. One of the difficulties encountered has been finding an adequate test method to evaluate the effecitiveness of the repairing. The influence of including expansive agents on the mechanical properties of the grouts was evaluated, as well as their expansive performance under uniaxial restraining conditions. The influence in the compressive strength depends on the used expansive agent type as well as the expansion performance, this last behavior strongly dependent on the expansive agent dosage considered. According to the obtained results, expansive grouts with 5% in weight cement content of expansive agent were used to evaluate their crack sealing efficacy. In order to overcome the difficulties encountered in previous works, the sealing efficacy of the grouts was evaluated by ad-hoc methods developed by the authors, in special cylindrical specimens of 150x300 mm where simulated cracks were made at the cross section center of the samples during the casting process. These cracks were sealed with the expansive grouts at 28 days of curing and, after that, the sealed samples were subjected to drying conditions during six months. After this exposure period, the efficacy of the sealing was evaluated by means of water permeability tests. The sealing efficacy of the expansive grouts was compared with that of a conventional grout. Both the mean and maximum water penetration depths were significantly reduced (¿80% of reduction) when using expansive grouts.
Development and characterization of expansive grouts for crack sealing.
The present paper deals with one of the main problems related to concrete structural elements, the tendency to crack as a consequence of its low tensile strength. This cracking limits the performance and durability of the concrete. Previous works by the authors showed the feasibility of using innovative expansive grouts in order to avoid or limit this cracking. These expansive grouts are based on the use of inorganic expansive agents promoting the increase of certain hydrates content. Two different agents were considered: type K (based on calcium sulfoaluminate) and type G (based on calcium oxide). The developed expansive grouts presented high penetration ability in the crack in order to prevent the ingress of aggressive agents and regain (totally or partially) the initial uncracked concrete mechanical properties. One of the difficulties encountered has been finding an adequate test method to evaluate the effecitiveness of the repairing. The influence of including expansive agents on the mechanical properties of the grouts was evaluated, as well as their expansive performance under uniaxial restraining conditions. The influence in the compressive strength depends on the used expansive agent type as well as the expansion performance, this last behavior strongly dependent on the expansive agent dosage considered. According to the obtained results, expansive grouts with 5% in weight cement content of expansive agent were used to evaluate their crack sealing efficacy. In order to overcome the difficulties encountered in previous works, the sealing efficacy of the grouts was evaluated by ad-hoc methods developed by the authors, in special cylindrical specimens of 150x300 mm where simulated cracks were made at the cross section center of the samples during the casting process. These cracks were sealed with the expansive grouts at 28 days of curing and, after that, the sealed samples were subjected to drying conditions during six months. After this exposure period, the efficacy of the sealing was evaluated by means of water permeability tests. The sealing efficacy of the expansive grouts was compared with that of a conventional grout. Both the mean and maximum water penetration depths were significantly reduced (¿80% of reduction) when using expansive grouts.
Development and characterization of expansive grouts for crack sealing.
García Calvo, José Luis (author) / Pedrosa, Filipe (author) / Carballosa, Pedro (author) / Revuelta Crespo, David (author)
2020-01-01
Miscellaneous
Electronic Resource
English
DDC:
690
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