The burnt lime is what concept
In the process of lime production, the temperature in the center of the stone did not reach 815 degrees, and the calcium carbonate could not be decomposed before it was discharged from the kiln. Such lime is called burnt limeDepending on the crystallization and drying of lime carbonation and hardening, the amount of carbon dioxide in the air of low calcium carbonate crust formation and carbonized carbon dioxide to prevent internal penetration, also prevent water evaporation outward, thus hardening slowly, the compressive strength is not high, 1:3 28 d lime mortar compressive strength is only 0.0.5 in MPa. humid environment, lime moisture evaporation, carbon dioxide cannot penetrate, hardening will cease; and the calcium hydroxide soluble in water, the hardened lime water will be dissolved away. Therefore, the lime is used in long period and wet by water environment.Lime in the hardening process, to evaporate large amounts of water, causing a significant volume shrinkage, prone to shrinkage cracks. Therefore, the lime is used alone, usually mixed sand, paper, hemp and other materials, to reduce shrinkage, increase tensile strength, and can save lime.Lime is strongly alkaline and can react with glassy reactive silica or activated alumina at ambient temperature to produce hydraulic products that produce cementation. Therefore, lime is an important raw material in the building materials industry
We usually say the effective content of lime is the calcium oxide content in lime (CaO) and Magnesium Oxide (MgO) content, the strength of these two substances of two ash macadam plays a decisive role, especially the hydration reaction and fly ash, the content of the play effect is more significant, increase the dose of lime limited nature can improve two ash gravel strength, but it will increase the construction cost, and to improve the crack resistance of two ash macadam is also very unfavorable, therefore, should try to select the high effective content of white ash, usually require lime must reach the standard two level grey more than that, the content of effective calcium and Magnesium Oxide in lime is not less than 80%, so as to meet the needs of two ash macadam oxidation and hydration process, ensure the basic strength, but also can improve the stability effect of the grass-roots level, does not affect its crack resistance Yes, it is very beneficial to ensure the quality of the grass roots
Lime digestion is an important link in the construction mixing, concrete construction to effectively control the process of digestion, lime is actually a CaO (MgO) hydration exothermic (H2O) reflect a process, to properly control the amount of water and water velocity, the slaking lime that is not too dry and the "dust", not too wet and "weak bond", the surface seems to be loose, the measured content of not more than 35%, in favor of two lime stone mixture mixing, the actual construction is usually adopted in advance to make digestion, stuffing, cover and sieving to meet the construction needs (advance digestion time is generally 7-10 days).
