the range of from about 3 to about 10 in an embodiment the wellbore servicing composition comprises a calcium aluminate cement cac which comprises calcium aluminum and oxygen and sets and hardens by reaction with water herein a cac refers to a cement having from about 35 to about 80 by weight of calcium aluminate such cements may further comprise small amounts of iron oxides and silica in some embodiments the cac comprises a phosphate salt in an embodiment the phosphate salts are polymeric phosphate salts of alkali metal salts for example and without limitation sodium metaphosphate in some embodiments the cac further comprises a flyash filler in such embodiments the flyash may comprise astm class f flyash such cac compositions comprising calcium aluminate phosphate salt and flyash are described in u s pat nos 5 900 053 6 143 069 and 6 332 921 each of which are incorporated by reference herein in its entirety examples of suitable cac materials include without limitation secar 41 secar 60 secar 51 and secar 71 which are calcium aluminate hydraulic cements commercially available from lafarge aluminates cheasapeake va ca 14 ca 270 and ca 25 grade calcium aluminate cements commercially available from almatis inc leetsdale pa and thermalock cement which is a blend of calcium aluminate cement comprising calcium aluminate a phosphate salt and flyash commercially available from halliburton energy services the set retarders to be disclosed herein are less effective and may have the opposite effect when used in combination with portland cements e g class a c g and h cements and thus the cementitious material preferably excludes such portland cements.