A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Mix proportion and properties of fire-resistant wet-mixed high-strength polypropylene fiber-reinforced sprayed polymer cement composites
The objective of this study was to determine the optimal mixture ratio of fire-resistant wet-mixed high-strength polypropylene fiber-reinforced sprayed polymer cement composite that would reduce the falling-off and exfoliation risk in tunnels and underground concrete structures, improve the construction efficiency of such tunnels, and improve the fire-resistance of the concrete. The conclusions of this study are as follows: A target compressive strength of 40 MPa was set to meet the study objectives. The cement based polymer composite mix included perlite, which has a low thermal conductivity, for providing insulation and polypropylene fiber to prevent spalling. The compressive and flexural strengths of the polypropylene fiber mixture were greater than 40 MPa and 5 MPa, respectively. Bond strength tests revealed strengths of 1.57 MPa to 1.79 MPa, which exceeded the required surface pressures described in the ITA guideline manual. As the mixture ratio of polypropylene fiber increased, the bond strength decreased since the polypropylene fiber mixture lowered the bond strength between the cement paste and aggregate. Spalling is caused by the internal void pressure generated from expansion due to heating. Accordingly, spalling occurs when the internal pressure exceeds the strength of the mortar and concrete. The fire-resistance tests demonstrated that spalling did not occur when the volume fraction of polypropylene fiber included in the fire-resistant polymer cement composite was greater than 0.2%. After the fire-resistance test, the weight of the specimens was 86% to 88% of the original value due to the polypropylene fiber dissolution and disintegration of the Ca(OH)2 in the cement paste. After the fire-resistance test, the residual compressive strength and flexural strength of the specimens were 31% to 32% and 28% to 31% of the original values, respectively. The polypropylene fiber effectively prevented the spalling of concrete but did not prevent the strength of the concrete from decreasing. The strength decrease was caused by deformation of the aggregate exposed to temperatures of 1200 deg C, the combined strength decrease of the cement paste and aggregate due to the Ca(OH)2 disintegration, the micro-cracks caused by the heat, and the void created after the polypropylene fiber dissolution.
Mix proportion and properties of fire-resistant wet-mixed high-strength polypropylene fiber-reinforced sprayed polymer cement composites
The objective of this study was to determine the optimal mixture ratio of fire-resistant wet-mixed high-strength polypropylene fiber-reinforced sprayed polymer cement composite that would reduce the falling-off and exfoliation risk in tunnels and underground concrete structures, improve the construction efficiency of such tunnels, and improve the fire-resistance of the concrete. The conclusions of this study are as follows: A target compressive strength of 40 MPa was set to meet the study objectives. The cement based polymer composite mix included perlite, which has a low thermal conductivity, for providing insulation and polypropylene fiber to prevent spalling. The compressive and flexural strengths of the polypropylene fiber mixture were greater than 40 MPa and 5 MPa, respectively. Bond strength tests revealed strengths of 1.57 MPa to 1.79 MPa, which exceeded the required surface pressures described in the ITA guideline manual. As the mixture ratio of polypropylene fiber increased, the bond strength decreased since the polypropylene fiber mixture lowered the bond strength between the cement paste and aggregate. Spalling is caused by the internal void pressure generated from expansion due to heating. Accordingly, spalling occurs when the internal pressure exceeds the strength of the mortar and concrete. The fire-resistance tests demonstrated that spalling did not occur when the volume fraction of polypropylene fiber included in the fire-resistant polymer cement composite was greater than 0.2%. After the fire-resistance test, the weight of the specimens was 86% to 88% of the original value due to the polypropylene fiber dissolution and disintegration of the Ca(OH)2 in the cement paste. After the fire-resistance test, the residual compressive strength and flexural strength of the specimens were 31% to 32% and 28% to 31% of the original values, respectively. The polypropylene fiber effectively prevented the spalling of concrete but did not prevent the strength of the concrete from decreasing. The strength decrease was caused by deformation of the aggregate exposed to temperatures of 1200 deg C, the combined strength decrease of the cement paste and aggregate due to the Ca(OH)2 disintegration, the micro-cracks caused by the heat, and the void created after the polypropylene fiber dissolution.
Mix proportion and properties of fire-resistant wet-mixed high-strength polypropylene fiber-reinforced sprayed polymer cement composites
Won, Jon-Pil (author) / Choi, Sek-Won (author) / Lee, Sang-Woo (author) / Jang, Chang-Il (author) / Lee, Su-Jin (author)
2010
10 Seiten, 11 Bilder, 6 Tabellen, 12 Quellen
Conference paper
English
Abplatzen , Anwendungsbeispiele , Biegefestigkeit , Bindefestigkeit , Calciumhydroxid , Druckfestigkeit , elektrische Isolation , faserverstärkter Verbundwerkstoff , Feuerfestigkeit , Flächenpressung , Gemisch , Hohlraum , Innendruck , Konzentration , Mikroriss , Mörtel , Perlit (vulkanisch) , Polymer , Polypropylenfaser , Richtlinie , Schichtkorrosion , Temperatur , thermische Leitfähigkeit , Tiefbau , Tunnel , Wärmeausdehnung , Zement , Zementpaste
POLYPROPYLENE FIBER FOR FIBER CEMENT-REINFORCED COMPOSITES
| European Patent Office | 2025
POLYPROPYLENE FIBER FOR FIBER CEMENT-REINFORCED COMPOSITES
| European Patent Office | 2023
| British Library Online Contents | 2011