Slump can be increased by adding chemical admixtures such as mid-range or high-range water reducing agents (super-plasticizers) without changing the water/cement ratio. It is bad practice to add excessive water upon delivery to the job site; however in a properly designed mixture it is important to reasonably achieve the specified slump prior to placement as design factors such as air content, internal water for hydration/strength gain, etc. are dependent on placement at design slump values.Henan Daswell Machinery Co., Ltd,is a professional manufacturer and trader specializing in the research, development and production of construction machinery for nearly 30 years. Our main products are as follows:portable concrete mixer,concrete pump,etc. We will provide you with the best product and service. The gradation change has great effects on the slump of concrete, water content and cover in the same case, slump is far less than the coarse material of concrete fine aggregate concrete slump, barn with concrete mix production process to aggregate material when you want to keep the cartridge on aggregate gradation is relatively stable concrete batching plants, so as to ensure that the grading of concrete distribution. The gradation change has great effects on the slump of concrete, water content and cover in the same case, slump is far less than the coarse material of concrete fine aggregate concrete slump, barn with concrete mix production process to aggregate material when you want to keep the cartridge on aggregate gradation is relatively stable concrete batching plants, so as to ensure that the grading of concrete distribution.