Effect Of Basalt On Properties Of Cement-based Materials For Moon

At present,China has achieved remarkable achievements in various aspects,and its overall national strength has been greatly improved.Especially in the area of astronautics,China,which started very late,with the continuous catch-up in recent decades,has become one of the greatest countries for astronautics.To face the fierce competition in the world today,space has become another big platform for demonstrating comprehensive national strength.As the space fever heats up,the moon once again enters into people’s vision.The moon is not only rich in mineral resources,but also an important springboard for humankind’s deep space,so the development of the moon and the construction of the lunar base will surely become the trend in the future.Due to the existence of a large number of basalt in the lunar sea,it can be assumed that cement and other materials will be taken to the moon and mixed with lunar basalt to produce high-strength lunar cement by dry-mix/steam-injection method（DMSIM）.In this paper,the properties of cement paste and cement mortar containing basalt powder prepared by DMSIM were investigated.The influence of the content of basalt powder and the curing time on the properties of the cement base materials used in the moon was studied through analyzing XRD and the physical properties,such as water absorption,compressive strength and volumetric density of specimen.At the same time,the experimental results of DMSIM were compared with the sample prepared by wet-mix/steam-injection method（WMSIM）.The results of the experiment are listed below:（1）The compressive strength of cement paste prepared by DMSIM decreased with the increase of basalt content first,then increased slightly（peak in 50%）and finally decreased,and the compressive strength of pure cement sample was the largest;the compressive strength of cement paste prepared by WMSIM and prepared by wet-mix cured in water at 20℃till28 days（WMCIW）was gradually decreased with the increase of basalt content（0%,20%,40%,60%and 80%）.（2）The compressive strength of cement paste prepared by WMSIM was lower than that of cement paste prepared by DMSIM under the same amount of basalt;when the amount of basalt was 40%,60%and 80%,the compressive strength of cement paste prepared by DMSIM was greater than that of cement paste prepared by WMCIW;when the amount of basalt was 60%and 80%,the compressive strength of cement paste prepared by WMSIM was greater than that of cement paste prepared by WMCIW.（3）The compressive strength of cement mortar prepared by DMSIM decreased with the increase of basalt content first,then increased slightly（peak in 40%）and finally decreased,and the compressive strength of cement mortar without basalt was the largest;the compressive strength of cement mortar prepared by WMSIM was increased with the increase of basalt content（0%,20%,40%,60%and 80%）first and then decreased,with maximum value at 20%basalt.The compressive strength of cement mortar prepared by WMCIW was gradually decreased with the increase of basalt content.（4）The compressive strength of cement mortar prepared by WMSIM and prepared by WMCIW was lower than that of cement paste prepared by DMSIM under the same amount of basalt;when the amount of basalt was20%,40%,60%and 80%,the compressive strength of cement mortar prepared by WMSIM was greater than that of cement mortar prepared by WMCIW.（5）With the increase of the amount of basalt,the change of water-binder ratio,non-evaporated water-binder ratio and bulk density were similar to the compressive strength.X-ray diffraction analysis showed that at 20%basalt,there was no hydration product Ca（OH）₂ in the sample,and the excess basalt occurred obviously when the content of basalt was 50%.（6）With the extension of autoclaving time,the compressive strength of cement paste prepared by DMSIM increased first and then decreased,and the best autoclave curing time was different for the content of basalt.