PROBLEM TO BE SOLVED: To provide a hydraulic composition containing no additive and excellent in fluidity even in a low water mixing ratio, and a hydraulic powder as a main component of the hydraulic composition.SOLUTION: A method for treating a hydraulic powder includes a step of exposing the hydraulic powder to ozone. A method for manufacturing a hydraulic composition includes a step of mixing the hydraulic powder and a kneading liquid. The hydraulic powder preferably has biocompatibility.【課題】添加物を含まず、かつ低い混水比であっても流動性に優れる水硬性組成物およびその主成分である水硬性粉末を提供する。【解決手段】水硬性粉末をオゾンに暴露する工程を含む水硬性粉末の処理方法、ならびに前記水硬性粉末と練和液とを混合する工程を含む水硬性組成物の製造方法。前記水硬性粉末は、生体適合性を有することが好ましい。【選択図】なし
