CEMENT MORTAR SPRAYING METHOD

PROBLEM TO BE SOLVED: To provide a cement mortar spraying method that is superior in pumpability, enables high ejection properties to be obtained more than a conventional spraying material, improved in thickness blowing properties, is superior in strength development in a short time after spraying, and is equal to or more than a conventional repairing material in plasterer finishing properties.SOLUTION: A cement mortar composition contains, to cement of 100 pts. Mass, an aggregate of 100-300 pts. mass, a quick hardening material of 1-15 pts. mass, a shrinkage reducing agent of 0.1-8.0 pts. mass, a short fiber of 12 mm or less in length of 0.05-2.0 pts. mass, a fluidizing agent of 0.02-1.0 pts. mass and a setting retarder of 0.1-1.0 pts. mass. Water is added and kneaded/mixed so that a water/cement ratio may become 30-55 mass%. Kneaded/mixed mortar A having a time to initial setting of 120-175 minutes is prepared. The kneaded/mixed mortar A is forcibly fed by a mortar conveying pipe 2 using a mortar pump 1 within 90 minutes just after being kneaded and mixed. The compressed-air B is introduced to a mixing pipe 3 for coupling between the mortar conveying pipe 2 and a nozzle 4, and the kneaded/mixed mortar is blown from the nozzle 4.SELECTED DRAWING: Figure 1 【課題】ポンプ圧送性に優れ、従来の吹付け材料よりも高吐出性が得られ、厚吹き性が向上し、吹付け後から短時間における強度発現性に優れ、左官仕上げ性においても従来の補修材と同等以上であるセメントモルタル吹付け工法を提供する。【解決手段】セメント100質量部に対して、骨材100〜300質量部、急硬材１〜15質量部、収縮低減剤0.1〜8.0質量部、長さ12mm以下の短繊維0.05〜2.0質量部、流動化剤0.02〜1.0質量部、及び凝結遅延剤0.1〜1.0質量部を含有し、水／セメント比が30〜55質量％となるように水を加えて練混ぜ、凝結始発までの時間が120〜175分の練混ぜモルタルＡを調製し、練混ぜ直後から90分以内にモルタルポンプ１により練混ぜモルタルＡをモルタル圧送管２で圧送し、モルタル圧送管２とノズル４の間を連結する混合管３に圧縮空気Ｂを導入して練混ぜモルタルをノズル４から吹付ける。【選択図】図１