Effect on the Flow Properties of the Mortar Using Micro-Nano Bubbles

Abstract

Bubble of which diameter ranges 50μm to nanometer-order is called micro-nanobubble (here in after “MNB”), it has properties different from the millimeter-order and centimeter-order naturally generated. In general, the bubble rises rapidly in water and burst at the surface. However, the MNB tends to stay in the water as the diameter of itself becomes small. In addition, MNB has various characteristics unlike general water. A typical characteristic includes water purification effect, and is utilized such as water treatment, agricultural industry and chemical industry. However, there is not much report that was utilized in the construction sector so far. In this study, it paid attention to the feature of MNB that the resistance when flowing in the tube decreases, and the possibility of the workability improvement of the grout material and the filling material by the use of MNB was investigated by the experiment of the cement paste. As the results, when it compared properties of the paste that used both MNB and tap water, no difference was observed in the air content and the flow value. However, plastic viscosity of the paste that used MNB was smaller than control paste. In consequence it was confirmed that the flow speed of the paste when it flows in the pipe was improved. On the other hand there is no difference in the compressive strength.

The effect of water to cement ratio and age on the mechanical properties of cement mortar and concrete made of micro‐nano bubbles without adding any admixtures

“…The achieved results of our study are in an agreement with previous studies 9,10,12 . Maruyama et al and Arefi et al stated a slump reduction in samples made of WMNB when water to cement ratio equals to 0.4 and 0.6, respectively 9,10 .…”

“…The achieved results of our study are in an agreement with previous studies 9,10,12 . Maruyama et al and Arefi et al stated a slump reduction in samples made of WMNB when water to cement ratio equals to 0.4 and 0.6, respectively 9,10 . Khoshroo et al also indicated that the slump of concrete decreases, even while using a combination of micro‐nano bubbles and superplasticizer additive simultaneously 12 …”

“…Although in their experiments Petro cock ash was used instead of cement, it can be found from the results that utilizing micro‐nano bubble of air in contact with Portland cement type II has similar behavior in increasing the compressive strength with when the micro‐nano bubble of hydrogen and Petro cock ash are used. In spite, Maruyama et al reported that the compressive strength of mortar samples containing a micro‐nano bubble is similar to control samples 9 . They used polycarboxylate ether (PCE) based superplasticizers admixture in cement paste and mortar mix designs.…”

“…Furthermore, Asadollahfardi et al reported that replacing 100% of drinking water by combination of micro‐nano bubbles water and superplasticizer rises the compressive strength, tensile strength, concrete resistivity, and water absorption of concrete specimens at the age of 28 days amounting around 13, 20, 165, and 67%, respectively 14 . According to the previous studies, 7–14 the micro‐nano bubble has the potential to use as a nano‐additive with or without other admixtures. However, studies on the micro‐nano bubbles were limited to the conventional concrete and its effect on the high strength concrete has not been reported in the articles until now.…”

“…They reported that nanobubbles could improve the average compressive strength of up to 25 and 8% at 7 and 24 days, respectively. In the study of Maruyama et al 9 on the flow properties of the mortar made with micro‐nano bubble, it was indicated that the use of micro‐nano bubbles results in a reduction of the slump plastic viscosity. In spite, micro‐nano bubbles have no significant impact on the compressive strength of the concrete samples.…”