Cementitious pipes

A method of producing cementitious pipe suitable for below ground use, wherein said method includes forming a pipe having a tubular wall of fibre-reinforced cementitious matrix or material capable of exhibiting pseudo strain hardening (PSH) behaviour, said wall having a wall thickness to diameter ratio within a range, and wherein said forming and the cementitious material are controlled whereby the range for said wall thickness to diameter ratio is such that the pipe exhibits characteristic behaviour in diametral quasi-static bending (flexure) when subjected to the 3-edge bearing method, and such said behaviour is such that a resultant stress versus relative displacement curve for the pipe when subjected to that method exhibits a substantially linear elastic region having a first slope within first limits and, from the limit of proportionality (LOP) for the elastic region to the modulus of rupture (MOR) for the pipe, a PSH region which, beyond a possible transition region, has a slope which is less than that of the elastic region and is within second limits.

The method of any one of claims 27 to 39, wherein the pipe is produced by dewatering extrusion of a suitable cementitious material having a water content providing a ratio of water to binder (cement plus pozzolanic) of about 0.3 to 0.5, and wherein the ratio is reduced during extrusion to about 0.24 to 0.26.