History of cement and concrete
{"Image DocumentName": "History of cement and concrete", "Image ImageDescription": "Non-hydraulic cements. Gypsum and lime. Cements based on compounds of lime (calcareous cements) Gypsum. Calcining impure gypsum at 130 \u00b0C. Add water calcined gypsum and water recombine. Cannot harden under water because gypsum is quite soluble. Pyramid of Cheops (3000 B.C.)", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}