One way to make normal concrete waterproof is to add a waterproofing admixture to the concrete mix. This admixture can help to reduce the porosity of the concrete, making it more resistant to water penetration. Another method is to apply a waterproofing sealer or coating to the surface of the cured concrete. This can help to create a barrier that prevents water from seeping into the concrete. Additionally, using a lower water-to-cement ratio in the concrete mix can also help to improve its waterproofing properties. **

Yes, you may compact the concrete slabs. Compacting the slabs will help to ensure that they are properly settled and will provide a more stable foundation. However, it is important to use the appropriate compaction equipment and techniques to avoid damaging the slabs. Additionally, it is important to follow any specific guidelines or recommendations provided by the manufacturer or engineer to ensure the best results. **

To waterproof an old concrete swimming pool, you can start by thoroughly cleaning the surface to remove any dirt, debris, and old sealant. Then, you can apply a waterproofing sealant specifically designed for concrete surfaces. This sealant will create a protective barrier against water penetration and help prevent leaks and cracks. Additionally, you can consider applying a waterproofing membrane or coating to provide extra protection. It's important to follow the manufacturer's instructions and ensure the surface is properly prepared before applying any waterproofing products. **

To apply concrete on concrete, the existing surface must be clean, free of debris, and properly moistened. A bonding agent or primer should be applied to the existing concrete to ensure adhesion. The fresh concrete mix can then be poured or pumped onto the existing surface and spread evenly using a screed or trowel. It is important to properly cure the new concrete to prevent cracking and ensure a strong bond between the two layers. **

Yes, it is possible to pour new concrete over old concrete as long as the existing concrete is in good condition and properly prepared. The old concrete should be clean, free of any loose debris, and roughened to provide a good bonding surface for the new concrete. Additionally, a bonding agent may be used to ensure a strong bond between the old and new concrete. It is important to consult with a professional to assess the condition of the existing concrete and determine the best approach for pouring new concrete over it. **

For setting lawn edging stones, garden concrete would be the better option. Garden concrete is specifically designed for outdoor use and is more durable and weather-resistant than concrete screed. It also has better adhesion properties, making it more suitable for securing the edging stones in place. Additionally, garden concrete is often formulated to be more resistant to cracking and shifting, which is important for maintaining the integrity of the lawn edging. **

To make Styrofoam waterproof for use in concrete casting, one can apply a waterproof sealant or coating to the surface of the Styrofoam. There are various waterproof sealants available that can be brushed or sprayed onto the Styrofoam to create a barrier against water. Additionally, one can also mix a waterproofing additive into the concrete mix itself to ensure that the Styrofoam remains protected from water during the casting process. It is important to thoroughly coat or treat the Styrofoam to prevent any water from seeping in and causing damage during the concrete casting process. **

It is unclear whether the concrete belt was poured with the wrong concrete based on the information provided. To determine if the wrong concrete was used, further investigation would be needed to compare the specifications of the concrete used with the requirements for the project. Factors such as strength, composition, and curing methods would need to be considered to determine if the concrete used was indeed incorrect. **