Effect of magnetized water on characteristics of sustainable concrete using volcanic ash

•VA is used as a supplementary cementitious material with and without MW to produce an eco-friendly concrete.•VA (0, 5, 10, 15 and 20%) and five different MW methods are experimentally designed to assess the concrete properties.•The workability of volcanic concrete increases by about 15% with MW.•The compressive strength increases by 33 % at 28 days with MW. Renewable resources of sustainable materials that can be functioned of supplementary cementitious materials are a critical in order to minimize extra waste, especially in construction mutter. Volcanic ash (VA) is one of natural pozzolanic material that can be considered important in Egypt. The main aim of the current study produces an eco-friendly concrete using the natural material. For that this study experimentally deals with developing a sustainable concrete using VA, as a supplementary cementitious material, and assesses their characteristics with and without using a magnetic field. Five ratios of VA (0, 5, 10, 15 and 20 %) as a replacement of cement were used to prepare thirty mixes. Magnetized water (MW) was generated using two different intensity values, 1.6 and 1.4 Tesla (T), to assess different magnetization methods. In the current study, five different MW methods were carried out based on the water pass direction and speed using a designed device. The results show that: (1) VA is thermally stable up to 800 °C, (2) The best ratio of VA for producing volcanic concrete is 5 % with tap water and MW, (3) The long direction and high speed of water through 1.6 then 1.4 T (which generate more friction between water and inner surface of pipes) is the best to produce more influence MW for volcanic concrete; this method improved pH of used water by 12.6 %, (4) The workability of volcanic concrete increases by about 15 % with MW, (5) Compressive strength of concrete is improved by 24 % at 7 days with 5 % VA and tap water, (6) Compressive strength increases with MW and 5 % VA up to 22 % and 33 % at 7 and 28 days, respectively. The results reveal that volcanic concrete characteristics are associated with the thermal stability of VA and the improved pH of used water.