Analysis of high-strength concrete compressive strength using extreme temperature mixed water added with admixtures for accelerating and retarding concreting

In the last few decades there has been a phenomenon of climate change triggering global warming. Nowadays, there is a need for concrete to have high bearing capacity and serviceability to build modern and advanced construction increases, which can be achieved by the use of high-strength concrete. This study aims to analyze the use of extreme temperature water as a mixture of high-strength concrete added with admixtures, i.e., accelerator and retarder to produce optimal compressive strength. The water used was hot (100˚C), cold (10˚C), and normal (23˚C). An accelerator was added to the mixture using cold water, while a retarder was added to the mixture containing hot water with the amount of accelerator and retarder used was 0%; 0.25%; 0.50%, and 0.75% from cement weight. High-strength concrete with compressive strength of 70 MPa (713.56 kg/cm2) having a water-cement ratio of 0.30 was made using cement of 550 kg/m3, split with maximum diameter 12 mm as coarse aggregate, added with silica fume 8% from cement weight and superplasticizer Viscocrete-10 1.5% from cement weight. A compressive strength test was carried out at the age of 28 days on the standard cylinder of 15/30 cm made based on variations in percentage of accelerator and retarder. The results showed that high-strength concretes using extreme temperatures mixed water added with accelerator and retarder affect the compressive strength. High-strength concrete containing cold water with accelerator produced the highest compressive strength at the addition of 0.25% accelerator by 679.83 kg/cm2, while the hot water mixture yielded the highest compressive strength with the addition of 0.25% retarder by 763.07 kg/cm2. High-strength concrete made with normal temperature water without admixtures resulted in compressive strength of 693.70 kg/cm2. The same finding was found towards material ductility measured from fracture energy of compressed cylinder. Hence, the optimum compressive strength was achieved at the addition of an accelerator and a retarder of 0.25%.