Testing hardened concrete. Determination of the shrinkage of concrete

2020 ◽  
Keyword(s):  
2018 ◽  
Vol 760 ◽  
pp. 204-209 ◽  
Author(s):  
Magdaléna Šefflová

This study deals with determination of the properties of the fine recycled aggregate (FRA) concrete with partial replacement of natural sand in concrete mixtures. The FRA was obtained from concrete waste and crushed on fraction 0 – 4 mm by laboratory jaw crusher. The geometrical and physical properties of natural sand and the FRA were tested. The main goal of this study is evaluation of the basic physical and mechanical properties of the concrete with partial natural sand replacement by the FRA such as workability, water absorption capacity, compressive strength and flexural strength. A total four concrete mixtures were prepared. The first concrete mixture was prepared only with natural sand, did not include the FRA. In other concrete mixtures, natural sand was replaced by the FRA in various replacement ratios (40 %, 50 %, and 60 %). All concrete mixtures were designated with the same parameters for clear comparison. The workability of fresh concrete mixtures and physical and mechanical properties of hardened concrete were tested.


2016 ◽  
Vol 714 ◽  
pp. 165-170
Author(s):  
Dalibor Kocáb ◽  
Petr Misák ◽  
Monika Králíková ◽  
Tereza Komárková

The paper describes the results of an experiment performed as part of the GAČR 13-18870S project dealing with the durability characteristics of the surface layer of hardened concrete. The paper aims to evaluate the experimental determination of the influence of an air entraining additive on the resistance of cement concrete to water and defrosting chemicals. For the purposes of the experiment 4 mixtures were prepared which differed in the amount of air entraining additive and the amount of cement. The test results were evaluated using statistical analysis of experiment.


1995 ◽  
Vol 17 (1) ◽  
pp. 55 ◽  
Author(s):  
RD Hooton ◽  
RD Hooton ◽  
CA Rogers

2016 ◽  
Vol 249 ◽  
pp. 73-78 ◽  
Author(s):  
Vladimír Suchánek ◽  
Kateřina Hájková

This report deals with long term monitoring of durability properties of concrete using different weight doses of various kinds of additions. Particularly limestone, silica fume as a 50% suspension and blast furnace slag were used. Even though the basic recipe is based on the designed concrete, all the fresh concrete was made with a free-fall concrete mixer in the laboratory. This report deals with long-term monitoring of cement concrete surface resistance to water and defrosting chemicals (achieved 475 cycles). The article also describes results of following tests: determination of concrete frost resistance, depth of water penetration under pressure and depth of chloride penetration. Standard tests of fresh and hardened concrete specimens complement the experiment.


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