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Magnesiacore is a versatile, durable construction panel. Using magnesia cement, we’ve created a non-combustible, cement-hard, paperless board that’s more resistant than gypsum, cement, clay, wood, or paper panels—without plastics.

44,781,894 次观看 • 3 个月前 •via X (Twitter)

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I live in Lukenya, Machakos County, less than 40 kilometres from Nairobi. Directly across from my home lies Kilili village — a place politicians flood every election season to beg for votes. The village has about 500 residents, including over 300 school-going children. It boasts more than 20 unlicensed bars, 15 churches, and just six police officers stationed at the nearby Lukenya Police Post. When it rains, a seasonal river floods and completely cuts off access to Mountainview Primary School, which sits on the opposite side of the village. The Kilili village is densely populated, with families renting houses while working at stone quarries and cement factories. Fewer than 20 people, including me, live on my side of the river. During the rains, I stay put because even vehicles cannot cross the flooded river. Meanwhile, young children are forced to miss classes, while others risk their lives trying to wade through the dangerous waters. The school also lacks running water, so pupils must carry their own for drinking and handwashing. Cement giants like Bamburi Cement PLC and Mombasa Cement extract raw materials from our area, reap billions in profits, and contribute millions in levies to the county. Yet those levies come from the very parents whose children must wade through a river just to reach school — and who study without access to clean drinking water. This is not merely a weather problem. It is a glaring failure of leadership and service delivery. Machakos County’s budget for 2025/26 stands at KSh 10 billion. I am confident that Governor Wavinya Ndeti Oduwole, EGH can resolve this issue in a single day — before a child drowns — just as Governor Sakaja swiftly fixed some roads in Nairobi ahead of French President Macron’s visit.

The People’s President

39,391 次观看 • 3 个月前

Roman architecture is at centre of Europe’s visual allure. Sophisticated Roman structures have survived hundreds of centuries without renovation... In 103 AD Roman engineer Apollodorus of Damascus built a 1.1km bridge from stone and wood. Trajan’s Bridge was 19m from surface of river, 15m wide and capable of supporting the weight of hundreds of traversing Roman soldiers. It was only a few feet shorter than Sydney harbour bridge. Romans built a lot of West’s longest standing buildings. They were also the first civilisation to make bridges from concrete. Some of these ancient bridges stand now as they did day they were built. This is thanks to the structural innovations that were first used by Romans. And innovations that eventually helped shape contemporary bridge engineering. Alcántara Bridge is such a bridge, standing in Spain since 104 AD. Roman civil engineer Caius Julius Lacer was the man behind the bridge. His tomb stands nearby, with an epitaph that reads “I leave a bridge forever in the centuries of the world”. He wasn’t wrong. There is a rumour doing the rounds on web that Roman engineers in charge of building bridges had to stand beneath them as scaffolding was removed. Apparently, trepidation of tonnes of rock and debris falling and crushing you lead to some pretty tight structural planning. A more likely history is found in Roman Empire’s military expansion. To improve Roman access lines the empire formed guilds of skilled workers and thinkers who shared ideas and building principles. These early engineering guilds made important discoveries in structural design, in the materials and in the piers that supported the legs of the bridges. Romans had improved traditional footbridge by creating a bridge that maintained its structural integrity through the centre. To achieve this the Romans did not rely on steel beams running through the stone members, but instead on the tensile strength of the stones themselves. The shape of the arch allowed the bricks to be inserted at a curved angle until they joined at the peak of the arch with a keystone. This keystone was shaped as a trapezoid that used the weight of the stone and concrete in the bridge to compress the tapered stones together. This pressure formed a structure in the arch that required a tremendous amount of force to rupture. Where traditional bridges were at their weakest in the centre, the arch was at its strongest. Arch was a structural innovation in building design. But it wasn’t only thing Roman Empire contributed to construction. Romans were also unique in the materials they chose to build with. A natural cement called pozzolana was used by Romans as mortar for piers (legs) of their bridges. Not only is this cement said to be ecologically cleaner than today’s cement mixtures, but its also a cement that grows stronger over time. Pozzolana is still used in some countries. It’s made by combining two parts pozzolana (which is a type of slag that forms naturally from volcanic rock) with one part powdered lime. As early as 3rd Century BC, Romans used pozzolana instead of sand in concrete in their construction. This gave their structures supreme strength and stability. As not every bridge built by Romans had luxury of building its piers on land, Romans used cofferdams where the piers would fall within a body of water. Romans used cofferdam as temporary structure that allowed construction of a bridge pier in a space of water. Cofferdams that were used by Romans were simpler than ones used in contemporary construction, but their function is identical. First, Romans would dig a ring of timber logs into river bed. They would then fill gaps between logs with clay for waterproofing, before pumping water from inside circle of logs. Upon newly dry riverbed, Romans would construct pozzolana and stone piers. After construction had been completed ring of logs was removed and piers stood in riverbed like magic. 🎥© simple.history_ (IG) #archaeohistories

Archaeo - Histories

52,307 次观看 • 1 年前