外掺MgO混凝土压蒸安定性试验方法的探讨

通过对外掺MgO水泥净浆、砂浆和混凝土3种试件不同尺寸的压蒸试验表明,试件尺寸对压蒸膨胀率有明显的影响。其规律是:小试件的压蒸膨胀率最大,中试件的次之,大试件的最小。文中还研究了掺外加剂和粉煤灰、用标准砂和工程砂对压蒸膨胀率的影响,阐明了外掺MgO混凝土压蒸法与水泥净浆标压方法的主要区别。经过大量研究,提出采用实际工程的材料和混凝土配比,以一级配混凝土干筛试件进行压蒸试验来评价安定性的方法,以及以压蒸后试件的强度不降低为依据、以压蒸膨胀率不超过0.5%作为安定性标准。经过工程实例验证表明,该试验方法科学合理,符合工程实际。

Probing into Admixed MgO Concrete Autoclave Soundness Test Method

Autoclave tests of different size specimens of admixed MgO pure cement grout, mortar and concrete indicate that dimensions of the specinens have obvious influence on the autoclave expansion rates. The smallest specimen has the highest expansion rate and the biggest one has the lowerest expansion rate. Influences of adding admixture and flyash and use of standard sand and works sand on autoclave expansion rate are also studied. Main difference between admixed MgO concrete autoclave method and pure cement grout standard autoclave methed are stated. It is suggested that by use of practical engineering materials and concrete mix proportions, autoclave test of the concrete with the maximum aggregate size of 19mm dry screen specimen is used to evaluate the concrete autoclave soundness and the soundness criterion is based on that the autoclaved concrete spicimen strength does not reduced and the autoclave expansion rate does not exceed 0. 5%.