Behnam Mahboubi - Department of Civil Engineering, Faculty of Engineering, Kharazmi University, Tehran, Iran.
Zuhua Guo - Department of Civil Engineering, Soochow University, Jiangsu, China.
Hao Wu - Department of Civil Engineering, Soochow University, Jiangsu, China.

The present study mainly aims at the identification and laboratory production of geopolymer concrete with the increased resistance to acid attack. For this purpose, after evaluating the reactivity of the raw materials and their applicability in the production of geopolymer cement among the available aluminosilicate materials, the metakaolin pozzolan was selected as the appropriate raw material. After the selection of the binder and activator of sodium hydroxide, the alkali activation process was performed for the mixtures of raw materials. Then, for the initial estimate of the durability performance of geopolymer cement  in acidic media, the durability of concrete samples was investigated in 1M sulfuric acid for 7, 28 and 90 days. The results showed that the nano-silica and nano-clay are effective in improving the performance of geopolymer concrete, as the addition of 3% nano-silica resulted in the 0.44% increase in the strength of the geopolymer concrete. Also, the addition of 3% nano-clay led to the increase in the strength of geopolymer samples up to 0.54. In addition, the samples are more durable in acidic media, so the weight loss of nano-clay-containing geopolymer samples in 90 days is 1.2 times that of geopolymer concrete samples without this additive.

Geopolymer, acidic medium, Nano-clay, nano-silica, Compressive strength