Question 1: What are aggregates? Aggregates are granular loose materials used to prepare concrete or mortar, also called aggregates. Most of the ordinary aggregates are natural aggregates, and some are industrial waste aggregates (such as metallurgical slag, etc.)

Question 2: What is the gradation specification of aggregates? Different aggregates are mixed in a certain proportion. , generally refers to combining several aggregates of different specifications (some large and some small) to form a mixture, and the passing rate of each sieve hole of the mixture is the gradation. Simply put, gradation is the passing rate of a series of sieve holes after aggregate screening.

Question 3: What are the coarse aggregates and fine aggregates of concrete? In asphalt mixtures, coarse aggregates refer to gravel, crushed gravel, screening gravel and slag with a particle size greater than 2.36mm. etc.; in cement concrete, coarse aggregate refers to crushed gravel and crushed gravel with a particle size greater than 5 mm.

In asphalt mixtures, coarse aggregate refers to natural sand, artificial sand and stone chips with a particle size less than 2.36mm; in cement concrete, coarse aggregate refers to particles with a particle size greater than 5mm. Natural sand, artificial sand.

Question 4: What is asphalt aggregate? 1. Asphalt concrete is a general term for mixtures made by mixing various mineral materials and asphalt binders. Asphalt concrete is generally composed of coarse aggregate, fine aggregate, filler (mineral powder), asphalt, etc.

2. Aggregate refers to crushed stone, gravel, slag, natural sand, artificial sand, stone chips, cement, mineral powder, fly ash, etc. used in the mixture. Summary acts as skeleton and filler.

Question 5: What are primary aggregates and secondary aggregates? The lightweight aggregate used in lightweight aggregate concrete should comply with the requirements of the current national standards "Lightweight Aggregate and Its Test Methods Part 1: Lightweight Aggregate" (GB/T 17431.1) and "Expanded Perlite" (JC 209); expanded pearl Rock

Question 6: What are acidic aggregates and alkaline aggregates? The aggregates used in road paving can be divided into acidic aggregates and alkaline aggregates. Limestone is an alkaline aggregate, and granite is an alkaline aggregate. and quartz are acidic aggregates. But the actual situation is much more complicated. Aggregates rarely contain only one component. Even pure minerals generally contain both acidic and alkaline components. It just depends on the content.

The composition is judged by the SiO2 content. The acid-base charge theory of aggregates is divided into acid-base and acid-base based on surface charge conditions

Examples of acid-base and acid-base properties of SiO2% aggregates

>65% acidic granite and quartz are basically on the surface Negatively charged

52%~65% neutral diabase

<52% Alkaline limestone and dolomite are basically positively charged on the surface

Question 7: What do concrete aggregates include? 10 points There are natural aggregates and artificial aggregates. The former such as gravel, pebbles, pumice, natural sand, etc.; the latter such as cinder, slag, ceramsite, expanded perlite, etc. Aggregates with particle apparent density less than 1700 kg/cubic meter are called light aggregates and are used to make ordinary concrete; particularly heavy aggregates are used to make heavy concrete, such as radiation-proof concrete. Aggregates are divided into coarse aggregates and fine aggregates according to particle size. Generally, those with a particle size greater than 5 mm are coarse aggregates, such as gravel and pebbles, and those with a particle size from 0.15 to 5 mm are fine aggregates, such as natural sand. .

Question 8: What are the coarse aggregate and fine aggregate of concrete? Coarse aggregate is pebbles or gravel. Fine aggregate is sand, as well as cementing materials such as cement, coal ash, ore powder, etc.

Question 9: What are lightweight aggregates in aggregate concrete? What are the specific ones? Thanks! 1. Classification of light aggregate

1) Classification according to particle size of light aggregate

(1) The particle size of light coarse aggregate is not less than 5mm, and the maximum bulk density is less than 1000Kg/ O;

(2) The particle size of light and fine aggregate is less than 5mm, and the maximum loose bulk density is less than 1200Kg/O.

2) Classification according to the source of lightweight aggregates

(1) Natural lightweight aggregates are naturally formed porous rocks and are processed into lightweight aggregates. Such as pumice, volcano and light sand.

(2) Artificial lightweight aggregate is a lightweight aggregate processed from local materials. Such as shale ceramsite, natural gangue, expanded slag beads, cinder and light sand.

(3) Industrial waste lightweight aggregate is a lightweight aggregate made from industrial waste as raw material. Such as fly ash ceramsite and shale ceramsite ground into balls.

3) Classification according to particle size of lightweight aggregate

(1) Spherical type

(2) Ordinary type

( 3) Gravel type 2. Lightweight aggregate concrete is divided into: natural light aggregate concrete according to the type of light aggregate. Such as pumice concrete, volcanic scoria concrete and porous tuff concrete. Artificial lightweight aggregate concrete. Such as clay ceramsite concrete, shale ceramsite concrete, expanded perlite concrete and concrete made of organic lightweight aggregates. Industrial waste lightweight aggregate concrete. Such as cinder concrete, fly ash ceramsite concrete and expanded slag bead concrete.

According to the type of concrete, it is divided into: full light concrete.

Lightweight aggregate concrete uses light sand as fine aggregate. Sand light concrete. Lightweight aggregate concrete that uses ordinary sand as fine aggregate partially or entirely.

Question 10: What does type b aggregate mean? After research, experiment, and development of a dry-mixed composite lightweight aggregate. It is mainly used to prepare lightweight aggregate concrete, thermal insulation mortar and refractory concrete, etc. It can also be used as thermal insulation loose filler.

Cities such as Beijing have restricted the use of clay ceramsite and shale ceramsite, and there is actually no supply of ceramsite. After research, experiments, and development of a dry-mix composite lightweight aggregate concrete cushion (referred to as "composite lightweight aggregate cushion") to replace ceramsite concrete, this dry-mix material can be constructed by adding water and mixing on site.

China is rich in natural light aggregate resources, especially in Northeast China, North China and Hainan Island. Natural lightweight aggregates are easy to mine, consume little energy in production, and are cheap. Some are not processed after mining, and some can be used after crushing and screening. The production process of artificial lightweight aggregate is more complicated and requires multiple processes such as raw material processing and roasting. The quality is better, but the energy consumption is large.