Bearing analysis - causes of cracking in the process of grouting material construction Bearing grouting material density

Bearing grouting material in bearing construction process of grouting materials, due to the negligence in the process of construction, prone to have a crack. Understand the reasons for this phenomenon, to avoid in the construction, the completion of the highest possible quality construction, the following is most likely to cause in the process of bearing grouting material construction cracks reasons: 1, single dosage of cement, the hydration heat of high & # 8195; ; Foundation bearing strength of grouting material level for C45, adopted by the grouting material mixture ratio, dosage of cement is 550 kg/M +, however, dosage of cement, hydration heat is high, the grouting material shrinkage is big also, so the cement strength grade 42. 28 d 5 r ordinary Portland cement, the hydration heat is also other varieties of cement hydration heat is high, the two factors also. Can affect cracks grouting material price professional manufacturers.   2, moulding temperature is too high & # 8195;       According to actual operation records, when sand in the open yard stacked, the temperature reaches 35 ℃, the cement temperature is 25 and commonly 30 ℃, mixing water temperature in the 15th & # 12316; 20 ℃, so the grouting material into the mold temperature 30 ℃, virtually increased the temperature inside the pedestal grouting material, also increases the grouting material inside and outside temperature difference, it is easier to promote the formation of cracks.   3, the temperature difference between inside and outside the bad control & # 8195; Bearing grouting materials do not match the temperature difference between inside and outside. To cause construction delay of project, the same. According to the calculation of temperature, in 3 d when the grouting material casting, foundation grouting material in the highest temperature is about 60 ℃, the grouting material maximum temperature difference inside and outside at this time is about 40 ℃, the local and outside wall cross section size of ( 0. 6 - 0. 8) M (0. Article 8 meters, the grouting material base surface coefficient is bigger, plus have been rain cooling flushing, and most in the outskirts of the construction site, on the outskirts of field empty, heat faster, cause there are large temperature gradient near the surface of the grouting material. Bearing compressive stress is generated in grouting material caused by grouting material exist near the surface of the larger temperature gradient. Compressive stress is generated in grouting material on the surface, The template surface) Produce large tensile stress, the grouting material (short, low tensile strength, grouting material inside and outside temperature difference T = 40 ℃ & gt; 25℃（ Specification) Because of the temperature difference between inside and outside surface tensile stress is greater than the limit tensile stress of grouting materials and produce a note and the top to the development of cracks, and the base profile template maintenance, heat slower, although a slight fracture is mild, but the general rule of surface crack width in the interior. Cracks tend to occur after grouting material pouring temperature stage, generally in the third day after grouting material casting crack. At this point the basis of the crack is produced after grouting material casting of 3 d temperature cracks. In front of the grouting material construction grouting material must be good control of the temperature difference between inside and outside, to estimate, ensure the smooth progress of construction. 4, shrink enough cooling control & # 8195;       Pedestal grouting material after pouring of 3 d, grouting material internal gradually cooling, cooling temperature and internal cause contraction, and internal mixing in the process of grouting material hardening of hydration and evaporation and the gelation of gel effect, easy to promote grouting material hardening contraction, in the process of contraction, based the restraint of basement rocks and anchor, naturally occurring within basis such large tensile stress, the tensile stress is greater than the tensile strength of grouting material, produced naturally from the basement up the development of cracks, due to the crack formation and structure is the weakest section, therefore, since the temperature of the surface cracks and the base of temperature shrinkage crack is connected the whole cross section, the formation of cracks in the form of the project.   5, improper measures maintenance & # 8195;       Pedestal grouting the maintenance measures of grouting material on how much water it is easier to cause the formation of cracks. On-site maintenance measures for grouting grouting materials on the first day of the material casting, the grouting material for each 0. 5 - 1 h wet curing time, and covering straw bag layer and water curing temperature is 25 degrees Celsius. Like appeared after the pouring rain, rain water temperature is 20 ℃ or so commonly, if not to make any cover bearing grouting material cause grouting material temperature up to 40 ℃, the formation of grouting material of the base surface heat faster, so also is the important cause of cracks.